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This is to certify that the

thesis entitled

A STUDY OF THE EFFECTS OF EXCITING THE INTAKE
FLOW IN AN INTERNAL COMBUSTION ENGINE MODEL

presented by

Greg Ambrose

has been accepted towards fulfillment
of the requirements for

M. S . degree in Mechanical Engineering

 

 

  

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DATE DUE

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ma mus-m4

 

A STUDY OF THE EFFECTS OF EXCITING THE INTAKE FLOW IN AN INTERNAL
COMBUSTION ENGINE MODEL

By

Greg Ambrose

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

MASTERS OF SCIENCE

Department of Mechanical Engineering

1 997

ABSTRACT
A STUDY OF THE EFFECTS OF EXCITING THE INTAKE FLOW IN AN
INTERNAL COMBUSTION ENGINE MODEL
By

Greg Ambrose

The motivation of this experiment was to determine if exciting the flow in an internal
combustion engine geometry could have positive effects on the developing large struc-
tures. The intent being a new method to improve the combustion process in internal com-
bustion engine applications, by controlling the in-cylinder flow characteristics. The
experiment used a water analog model of an internal combustion engine, and the focus of
the study was on the intake stroke. The shear layer formed by the flow entering through
the intake valve was perturbed by applying a disturbance about the nominal position of
the intake valve. Sinusoidal disturbances with peak to peak amplitudes of 0.35 mm and
1.00 mm and frequencies incrementing by 10 Hz from 10 Hz to 90 Hz were used to excite
the flow through various ranges of the intake stroke. The effects of these disturbances on
the flow were first examined with flow visualization techniques, and then velocity fields

were measured using Molecular Tagging Velocimetry (MTV).

The data, in the tumble plane, showed significant changes in the large scale flow struc-
tures. The MTV results of mean circulation and mean kinetic energy indicate up to a

40% increase in mean circulation, and a 30% increase in mean kinetic energy.

ACKNOWLEDGEMENTS

I would like to thank many of the people who have helped and assisted me in this work. I
would like to thank my advisor Dr. Manooch Koochesfahani, who was the originator of
the topic for this thesis, the members of my committee, Dr. Harold Schock and Dr. Daniel
Nocera. For technical assistance and input on many matters, I would like to thank Rich
Cohn, Thomas Stuecken, Bemd Stier, and CHuck Gendrich. Also a special thanks to the
Center of Fundamental Material Research (CFMR) and the Materials Research Science
and Engineering Center (MRSEC) at MSU funded by the National Science Foundation
(NSF), for supporting this project and the Ford Motor Company for the donation of the

equipment for the engine model.

iii

Chapter

TABLE OF CONTENTS
Title

List of Tables

List of Figures
List of Symbols

INTRODUCTION

EXPERIMENTAL SET-UP

2.1 Water Analog IC Engine Model

2.2 Flow Visualization Set-up

2.3 Molecular Tagging Velocimetry (MTV) Set-up
2.4 MTV Data Reduction

2.4.] Optical Distortions - Correction Method 1
2.4.2 Optical Distortions - Correction Method 2

RESULTS AND DISCUSSION

3.1 Flow Visualization Results

3.1.1 Effects of Excitation Amplitude - Flow Visualization
3.1.2 Effects of Excitation Frequency - Flow Visualization
3.1.3 Effects of Excitation Duration - Flow Visualization
3.2 MTV Results

3.2.1 Cycle Averaged Velocity and Vorticity Fields

3.2.2 Effects of the Number of Cycles used to Ensemble Average
3.2.3 Mean Circulation and Mean Kinetic Energy Results
3.2.4 Effects of Excitation Amplitude - MTV

3.2.5 Effects of Excitation Frequency - MTV

3.2.6 Effects of Excitation Duration - MTV

3.3 Other Parameters that could be Examined and Future Work

11
15
21
23

27
28
29
31
32
45
46
48
48
50
5 l
52
54

CONCLUSIONS 56

APPENDIX A: Flow Visualization Images at 340 RPM 78
APPENDIX B: MTV Ensemble Averaged Velocity Fields at 340 RPM 96
APPENDIX C: Plots of Statistical Quantities from the MTV data 1 14
REFERENCES 125

 

List of Tables

m; figs
Forcing Conditions Examined with Flow Visualization 1 1
Forcing Conditions Examined with MTV 15
Comparison of Cylinder Distortion Correction Techniques 25
Percent Change in Mean Circulation, Mean Tumble Ratio, Mean Kinetic Energy, 54

and Minimum Vorticity from No Excitation at 180 Degrees Crank Angle

vi

Fi gure

2a

2b
3a
3b

3c

10

11

12

13

List of Figures

Title

Assembly View of the Piston-Cylinder Set-Up and View of the Test Rig

Operating Cycle used for the Water Analog Model of an Internal
Combustion Engine.

Crank Shaft and Connecting Rod Assembly

Optical Arrangement for the MTV Set-Up

Examples of a Delayed and Undelayed Image with the MTV Method.
Coordinate System and Data Locations within the Cylinder

The Methodology for Converting Pixel Displacements to Velocity Com-
ponents (Method 1)

Method for Distortion Correction by Correcting the Images Directly
(Method 2)

Flow Visualization Comparisons at 170 RPM.

Comparison of Flow Visualization at 180 Degrees Crank Angle.
RPM: 340, A: 0.35 and 1.00 mm, A: 0-180 degrees

Comparison of Flow Visualization at 180 Degrees Crank Angle.
RPM: 340, A: 0.35 and 1.00 mm, A: 0-18 degrees

Comparison of Flow Visualization at 180 Degrees Crank Angle.
RPM: 340, A: 0.35 and 1.00 mm, A: 0-60 degrees

Flow Visualization at 340 RPM, No Excitation, Entire Intake Stroke

Flow Visualization at through the Entire Intake Stroke 340 RPM with
Excitation Conditions f. 40 Hz A: 0.35 mm A: 0-180

Flow Visualization at through the Entire Intake Stroke 340 RPM with
Excitation Conditions f: 40 Hz A: 1.00 mm A: 0—180

Flow Visualization at through the Entire Intake Stroke 340 RPM with
Excitation Conditions f. 60 Hz A: 1.00 mm A: 0-180

vii

12

l3

16

22

24

34

35

36

37

38

39

40

41

List of Figures

Figure T_itl_e
14 Flow Visualization at through the Entire Intake Stroke 340 RPM with Excitation

15

16

17

18

19

20

21

22

23

24

25

26

27

Conditions f: 40 Hz A: 0.35 mm A: 0-18

Flow Visualization at through the Entire Intake Stroke 340 RPM with Excitation
Conditions f: 60 Hz A: 0.35 mm A: 0-18

Flow Visualization at through the Entire Intake Stroke 340 RPM with Excitation
Conditions f: 60 Hz A: 0.35 mm A: 0-60

Cycle Averaged Velocity and Vorticity Fields with No Excitation

Cycle Averaged Velocity and Vorticity Fields with Excitation Conditions:
f: 40 Hz A: 0.35 mm A: 0—180 degrees

Cycle Averaged Velocity and Vorticity Fields with Excitation Conditions:
f: 40 Hz A: 1.00 mm A: 0-180 degrees

Cycle Averaged Velocity and Vorticity Fields with Excitation Conditions:
f: 60 Hz A: 1.00 mm A: 0-180 degrees

Cycle Averaged Velocity and Vorticity Fields with Excitation Conditions:
f: 40 Hz A: 0.35 mm A: 0-18 degrees

Cycle Averaged Velocity and Vorticity Fields with Excitation Conditions:
f: 60 Hz A: 0.35 mm A: 0-18 degrees

Cycle Averaged Velocity and Vorticity Fields with Excitation Conditions:
f: 40 Hz A: 0.35 mm A: 0-60 degrees

Effects of the Sample Size of Engine Cycles used for Ensemble Averaging on
Peak Vorticity, Tumble Ratio, and Kinetic Energy - No Excitation

Effects of the Sample Size of Engine Cycles used for Ensemble Averaging on
Circulation and Average Vorticity - No Excitation

Effects of the Sample Size of Engine Cycles used for Ensemble Averaging on
Peak Vorticity, Tumble Ratio, and Kinetic Energy - f: 60Hz A: 1.00mm A: 0-180

Effects of the Sample Size of Engine Cycles used for Ensemble Averaging on
Circulation and Average Vorticity - f: 60 Hz A: 1.00 mm A: 0-180

viii

57

58

59

60

61

62

63

64

65

66

Figure

28

29

3O

31

32

33

34

35

36

37

List of Figures

Title

Mean Circulation and Mean Kinetic Energy for A=0.35 mm, and All Con-
ditions with #40 and 60 Hz, A = 0-180, 0-60, and 0-18 degrees

Mean Circulation and Mean Kinetic Energy for A=1.00 mm, and All Con-
ditions with .f=4O and 60 Hz, A = 0-180, 0-60, and 0-18 degrees

Mean Circulation and Mean Kinetic Energy for fi- 20, 30, 40, and 60 Hz,
with A=1.00 mm and, A = 0-180 degrees

Percent Changes in Mean Circulation and Mean Kinetic Energy between
No Excitation to Cases with Forcing Amplitudes of 0.35 mm

Percent Changes in Mean Circulation and Mean Kinetic Energy between
No Excitation to Cases with Forcing Amplitudes of 1.00 mm

Percent Changes in Mean Circulation and Mean Kinetic Energy
from Increasing the Forcing Amplitude from 0.35 mm to 1.00 mm.

Percent Changes in Mean Circulation and Mean Kinetic Energy between
No Excitation and 20, 30, 40, and 60 Hz at A=1.00 mm, A=0-180 degrees.

Percent Changes in Mean Circulation and Mean Kinetic Energy between
No Excitation and Different Excitation Durations at 40 Hz

Percent Changes in Mean Circulation and Mean Kinetic Energy between
No Excitation and Cases with Forcing Frequencies of 60 Hz

Percent Changes in Mean Circulation and Mean Kinetic Energy when
Increasing the Excitation Frequency from 40 Hz to 60 Hz.

69

70

71

72

73

74

75

76

77

Overscores

~

Underscores

List of Symbols

Description

Peak to Peak Amplitude of the Excitation
Crank Angle

Characteristic Diameter

Frequency of the Excitation

Angular Momentum about the Z—Axis

Moment of Inertia about the Z-Axis

Kinetic Energy

Number of Engine Cycles
Reynolds Number
Revolutions per Minute
Strouhal Number (fD/U)

Tumble Ratio about the Z-Axis
Characteristic Velocity

X, Y, and Z Components of Velocity
Coordinate System Axis

vorticity

Crank Angle Range of the Intake which the Excitation is Activated
Circulation

Engine Speed in Cycles per Second

Engine Speed in Radians per Second

A Variable of Interest

RMS
Mean

Vector Representation

Chapter 1

INTRODUCTION

This study was undertaken to examine the effects of exciting the flow entering a piston-
cylinder arrangement. To date, studies of exciting the flow entering an internal combus-
tion engine have not been done; however, excited flows have been studied in other geom-
etries. In these other flow arrangements, such as round jets, coaxial jets, and two stream
mixing layers, it has been shown that perturbing the flow can modify the amount of the
mixing down stream of the wake and turbulence intensities [2,3,4,5]. Studies of the exci-
tation of round and coaxial jets have shown that excitation affects the way small vortical
structures in the inner and outer mixing layers combine to form larger ones, which can
change the large scale structures and promote turbulence. The desired results in the case
of the piston-cylinder arrangement would be a way of controlling the flow characteristics
to alter the large scale motions and increase turbulence. Control of turbulence in the bulk
flow should provide control of the mixing and burn rates of an internal combustion
engine; however, estimation of the direct impact of these changes in the flow on the per-

formance or efficiency of an actual engine was not attempted in this study.

The intake flow most closely resembles that of an annular jet, but it does have some major
differences, such as the time varying wall boundary conditions from the piston and cylin-
der, and a time varying mean velocity due to the sinusoidal movement of the piston.
Since to the author’s knowledge, no studies of excited annular jets have been done to

date, an excited coaxial jet is the closest geometry for a possible comparison to the cur-

rent literature. Studies of excited coaxial jets have been done by Tang and Ko [2], and
excited round jets by Zaman and Hussain [3,4]. Tang and Ko [2] studied excited coaxial
jets with an inner to outer jet velocity ratio (Ui/Uo) of 0.3 (U0 = 50 m/s). They found
broadband turbulence amplification when excited at a preferred Strouhal number of 1.16

(StD = fDo /U0, where f is the forcing frequency, DO is the diameter of the outer jet, and
U0 is the outer jet velocity), and a gradual decrease in the amplification as StD

approached 4.0. Zaman and Hussain [3,4] found that a turbulent or laminar single round
jet had amplification of turbulence when excited at Strouhal numbers in the range 0.25 to

1.2, with the maximum amplification of turbulence at StD = 0.85.

A water analog model of an internal combustion engine was used, and the flow was
excited by applying a disturbance about the nominal position of the intake valve. The
intake valve in this IC engine model was located at the center of the cylinder and kept
open at a fixed lift of 9 mm. Since water was used as the working fluid, the compression
stroke was not examined, so only the effects during the intake stroke were studied. The
excitation in this study was introduced by oscillating the intake valve to perturb its shear
layer during the intake stroke. Various disturbance conditions were selected to examine
structural changes in the flow on the basis of the disturbance’s frequency, amplitude, and

duration of the intake stroke when the excitation is active.

The effect of these disturbances on the bulk properties of the flow was first examined with
flow visualization techniques, and then velocity fields of selected cases were measured

using molecular tagging velocimetry, MTV, as done by Gendrich and Koochesfahani [l].

The flow visualization was performed at air equivalent engine speeds of 170 RPM, and
340 RPM. The velocimetry examined a speed of 340 RPM and a subset of the excitations

done in the flow visualization to quantify the effects.

To use the results from excited jet studies as a first estimate of the relevant range of Strou-
hal numbers in the piston-cylinder arrangement, the velocity term in the Strouhal number
has to be defined for the piston-cylinder flow. Since the flow through the intake valve is
not steady due to the motion of the piston, a simplification would be to use the maximum
mean velocity through the valve (at mid-stroke, CA=90 degrees)), to provide a single
number for the Strouhal number. The corresponding Strouhal Number would be,
StD = fD/U,

where f is the excitation frequency, D is a characteristic length of the geometry (i.e. valve
diameter), and U is a characteristic velocity of the flow (i.e. maximum mean velocity
through the valve opening). Using the above definition for the velocity in the Strouhal
number and the results for maximum turbulence amplification from the jet studies (i.e.

StD z 1), a first approximation for preferred excitation frequencies is 31.3 Hz at an engine

speed of 20 RPM (air equivalent speed of 340 RPM). Comparing the engine speed, O =

0.17 Hz (20 RPM), and the excitation frequency, f=3l.3 Hz, it is seen that f >> O.

In an effort to isolate the effects of the excitation parameters, sinusoidal disturbances of
various amplitudes, frequencies, and excitation duration periods were used to excite the
flow. The disturbances applied to the valve had amplitudes, A, of 0.35, 0.50, and 1.00

mm peak to peak, frequencies, f, incrementing by 10 Hz from 10 Hz to 90 Hz (this range

covers the first approximation for the preferred excitation frequencies), and excitation
was activated during periods in the intake stroke, A, from 0-180, 40-180, 60-180, 0-18, 0-
60 crank angle (CA) degrees, referenced to TDC (Top Dead Center) of the intake stroke.
An examination of the bulk flow characteristics was then carried out for both in the natu-

ral (i.e. unperturbed) and perturbed states to study their effects.

The organization of this paper is divided into three remaining chapters. In Chapter 2,
Experimental Equipment and Procedure, the engine model is first described, and then
equipment and procedure for the flow visualization and MTV data acquisition are
described. In the last part of Chapter 2, the MTV data reduction is described along with
data correction methods to account for optical distortions created from the curvature of
the cylinder. Chapter 3, Results and Discussion, examines selected flow visualization
images which are used to evaluate the effects of the forcing parameters (A, f, and A) on
the large scale motions near the end of the intake stroke. Chapter 3 continues with a dis-
cussion of the resulting cycle averaged velocity and vorticity fields from the MTV data
which are compared to corresponding flow visualization results. Next, the convergence
of the MTV data based on the number of engine cycles used in ensemble averaging is
examined for the unperturbed case and one of the excited cases. The MTV results are
used to evaluate the effects of the forcing parameters (A, f, and A) on the mean circulation
and the mean kinetic energy. Chapter 3 ends with a discussion of other aspects of this
study which could be examined in future studies in order to understand the effects of
exciting the flow. Chapter 4, Conclusions, summarizes the trends observed within this

study.

Chapter 2

EXPERIMENTAL EQUIPMENT AND PROCEDURE

2.1 The Water Analog Model of an Internal Combustion Engine.

The geometry of the piston cylinder arrangement, shown schematically in Figure 1, con-
sisted of a 82.0 mm-diameter cylinder with a stroke of 82.4 mm. The piston used was
flat, and incorporated Rulon rings for sealing with quartz and Polyethylene when sealing
against Plexiglass. The piston and cylinder used for MTV were made of quartz, and
Plexiglass was used for flow visualization. The valve diameter was 32 mm, and the lift
was set for 9 mm, since typical engines have a maximum lift in the range of 9 to 12 mm.
The valve was not operated by a cam as in a typical engine, but instead was held open at a
clearance of 9 mm. This was done because water was used as the working fluid, and
required the valve being open during the compression cycle. The source of excitation
was the valve which was displaced about its nominal position. An Alpha-K model AV—6
shaker driven by a function generator displaced the valve, and the position was monitored
by a Linear Variable Displacement Transducer (LVDT). The lowest amplitude that the
shaker could produce with long term consistency was 0.35 mm; to go to lower amplitudes
would often result in the motion slowly attenuating and occasionally stopping due to the
friction in the valve guide interface. The shaker could produce output amplitudes of 0.35
mm‘with frequencies up to 90 Hz in water without exceeding its maximum power rating,

and at amplitudes of 1.00 mm, the maximum frequency obtained was 60 Hz.

Shaker
Valve

Water RCSCI'VOII' Shaker Support

Shaker / Valve
lnterf ace

Shaker Support
Base

 

 

 

 

  

Cylinder

   

 

     

 

 

  

Brass Valve

Piston Head Valve Guide

Water Reservoir /

Intake for cylinder / \

 

 

 

 

 

Cylinder ’ ‘

Pismn %

cyhnder

     
 

Mirror , Cylindrical Lens, and
Spherical Lens

 

 

 

 

 

 

 

 

 

Laser Beam

--.---..--.»--..------..

 

 

 

 

 

 

 

 

 

Experimental Setup

Figure 1. Assembly view of the piston-cylinder set-up and view of
the test rig.

The engine cycle used for water analog model of the engine is plotted in Figure 2a, which
shows that the piston remains at BDC throughout the compression and power strokes, but
the intake and exhaust occur as normal, that should create acceptable initial conditions

for the intake stroke. This cycle was generated with the cam profile of the crank shaft

shown in Figure 2a.

   
 
  
  

Slot where the connecting rod Power Compression Center of
assembly travels Rotation of the
Crank Shaft

Index Pulse
Location
(10 degrees before TDC)

Piston Position

    

 

 

 

 

U2? Intake Compression Power Exhaust ETDC
C.A.
§>

-L/2~ - 5

: : : ' DC
270 360 540 720B

Figure 23. Operating cycle used for the water analog model of an
internal combustion engine.

The connecting rod mechanism was not allowed to have any horizontal motion; it fixed to

the piston at the top and the bottom was attached to the slot in the crank shaft with a roller
as shown in Figure 2b. As the crank shaft rotated, the connecting rod would be translated

up and down according to the cam profile shown in Figure 2a.

 

 

 

 

 

 

 

 

 

 

Cylinder
. Piston m Connecting Rod Assemble
Bearings Testing Rig Table
E Crank Shaft
[:3 Crank Shaft Slot
5 r
/
V//,///////// / ///////éA
é Roller é
/ /
é %
/ Shaft _ /
; ToEIptor ' i I» Crank-E": %
Z (Li: Shaft ‘ /

 

 

 

 

 

 

Figure 2b. Crank Shaft and Connecting Rod Assembly.

The piston was driven by a 2 HP DC motor, and the relative crank angle position was
monitored by an optical encoder with the precision of one encoder pulse. The encoder
output count was 360 per revolution for the flow visualization, and later with MTV it was
made to be 720 per revolution through a gearing change. Since a four stroke engine goes

through 720 degrees to complete one cycle and this model only goes through 360, the

crank angle position had a maximum error of 1 degree for the MTV results, and 2
degrees for the flow visualization results. Since the encoder output was a continuous
series of pulses, the absolute position of the crank angle measurement was located with
the addition of a secondary output of one pulse per revolution, which was used as a refer-

ence pulse located 10 degrees before TDC.

Water was used as the working fluid in the model for two main reasons. First, Since geo-
metric similitude was held between the model and a typical engine dimensions, charac-
teristic lengths are the same, so the velocity for the model engine scales as a ratio of the
kinematic viscosities between air and water for the same Reynolds number of a motored
engine using air as its working fluid. This results in a velocity, RPM, and valve forcing
frequency that scale to be 17 times larger than in air, so much lower speeds are required
for a reasonable air equivalent RPM, and the shaker which created the valve motion had a
much greater span of frequencies to excite the flow. The other reason for using water in
the model was the ease of seeding the fluid for flow visualization and for the introduction
of the chemicals required for MTV to generate the phosphorescence which convects with

the tagged flow.

2.2. Flow Visualization Set-up

Flow visualization was carried out to examine the qualitative effects of exciting the flow
through this method. The flow visualization utilized silver-coated hollow glass spheres to
seed the flow. Their size ranged from 10 to 12 microns, and were illuminated with a

Lexel Model 95 argon ion laser at 1.0 W. The image acquisition consisted of a NEC CCD

10

camera with an exposure time of 1/60 second and a Nikkor 50mm f 1.2 lens, as well as a
Data Translations DT3851 frame grabber, that is capable of storing 8 megabytes of
images to memory which was sufficient to capture interlaced imaged as 30 frames per
second over the time of the intake stroke. An A/D converter (ComputerBoards CIO-
D1024) simultaneously acquired the valve position from the LVDT and the crank angle
position from an encoder mounted to the crank shaft. The optics consisted of a 1000 mm
spherical lens to focus the beam and a 80 mm cylindrical lens to form a diverging plane
of laser light. The flow visualization was carried out for a tumble plane through the cyl-
inders vertical axis with a field of view which starts from the top of the cylinder to mid
stroke, and horizontally 10 mm from the center of the cylinder out to the cylinder wall, as

Shown below:
41 m

 

82.4 mm

 

 

 

11

All of the following excitation conditions were examined with flow visualization:

Table 1: Forcing Conditions Examined with Flow Visualization

 

 

 

 

Amp. Freq. Duration
RPM (mm) (HZ) (CA)
170 0.35, 0.50, 1.00 10, 20, 30,40, 50, 60 0-180
170 0.35, 1.00 10, 20, 30, 40, 50, 60 40-180

 

340 0.35, 0.50, 1.00 10, 20, 30, 40, 50, 60 0—180, 40-180, 60-180

 

340 0.35 70, 80, 90 40-180, 60-180, 0—18, 0—60

 

 

340 1.00 10, 20, 30, 40, 50, 60 0-18, 0-60

 

 

 

 

2.3 MTV Set-Up

Molecular Tagging Velocimetry, MTV, uses a working build which is pre-mixed with
molecules with long-lived luminescence. A pulsed laser is used to tag the flow in the
regions of interest, and the regions are imaged at two successive times within the lumi-
nescence lifetime. The measured Lagrangian displacement vector and the time over
which the displacement occurred provides the estimate of the velocity vector. For mea-
suring two components of the velocity, the intensity field of the tagged regions must have
spacial gradients in two, preferably orthogonal, directions. For a multi-point velocity

measurement, this is done by producing a grid of intersecting laser lines.

For MTV, a Lambda Physik LPX 200i UV (308 nm) laser operating at approximately 155
m] (18 kV) provided the energy to generate phosphorescence from a working fluid mix-
ture of 3.0 L of de-ionized water, 15.5 mL of CchH, 0.78 gm CD, and saturated with

Ber. This required the use of a quartz piston and cylinder for the transmittance of the

 

12

UV light. By using laser beam blockers to create a series of alternating thick and thin
laser lines, a nearly perpendicular grid pattern was imposed on the flow by generating one
series of laser lines through the bottom of the piston, and a second series of lines directed

through the cylinder, see Figure 3a,b.

 
 
 
  
      
 
 

Thick-Thin
Beam Blocker .
M1rror

300 mm
Cylindrical
Lens

Beam Splitter

    
    
       
  
  
   

Thick-Thin
Beam Blocker

150 mm
Cylindrical
Lens

50 mm Cylindrical
150 mm Cylindrical Lens

Incoming Laser Beam

Figure 3a. Optical Arrangement for the MTV Set-Up.

13

Figure 3a shows the optical arrangement. The laser beam was focused using a combina-
tion of two cylindrical lenses with focal lengths of 150mm and 50 mm. A beam splitter
was then used divide the beam in two. The divergence of each beam was then adjusted
with additional cylindrical lenses, one 300 mm lens for the vertical set of bea and a 150
mm lens for the horizontal beam. Beam blockers fabricated from metal plates with a
series of thin lines cut through them were placed in each beam path to generate a series of
12 to 13 lines. The MTV experiments were done with a field of View approximately 6cm
x 6cm, located 22 mm below the top of the cylinder and 0.5 cm from the cylinder wall,

see Figure 3b.

 

 

Image from the First Camera Image from the Delayed Camera
41 mm

.1
I Y '
lField of View: I Stroke:

|60mm x 60 mni 82.4 mm

L\ I
‘~J

 

Figure 3b. Example of a Delayed and Undelayed Image from the MTV Technique
and the Field of View within the Cylinder.
(images shown contain optical distortion from the cylinder)

 

 

 

14

Two Pulnix non-interlaced cameras with a 0.25 msec shutter Speed and Nikkor 50 mm

f 1.2 lenses viewed the same region of the flow through a beam splitter. A video signal
generator created horizontal and vertical drive inputs for the two cameras, and the vertical
drive pulse was the source for the synchronization of the two cameras, the A/D acquisi-
tion, and the laser pulse triggering. The laser was triggered early enough (15.0961 msec)
relative to the first camera’s vertical drive such that the fluorescence range of the emission
would disappear (l usec after the occurrence of the peak intensity), and only phosphores—
cence would exist. Digital delay generators were used to delay the first camera relative to
the laser firing time, and delayed the second camera relative to the first camera by 2.0226
msec which would provide approximately 5 to 10 pixels of displacement of the phospho-

rescent grid lines. See Figure 3b for an example of an image from each camera.

The image acquisition system was a Trapix Plus. The Trapix Plus is a real time image
acquisition system capable of storing up to 8 gigabytes of continuous 8 bit 512k by 512k
images from the two camera arrangement. The crank angle data was acquired in the
same manner as the flow visualization experiments using a ComputerBoards CIO-D1024.
The framing rate from the Pulnix cameras was free running at a rate of 1/30 sec (approxi-
mately every 4 crank angle degrees) throughout the duration of the intake stroke and the
DC motor driving the piston was also free running, but at a varying rate since the speed of
the motor would drift Slightly. Therefore the image acquisition was not phase locked to
the crank angle position, and the image acquisition would not occur at the same crank
angle locations throughout the stroke, even if the first image always occurred at the same

location. The absolute crank angle position was monitored by from the encoder with the

15

A/D board, and was used to gate the initiation of the image acquisition. The onset of the
image acquisition would have the Trapix Plus computer trigger data collection from the
crank angle encoder each time a frame was acquired. AS an attempt to increase the num-
ber of common crank angle positions between cycles, the cycles were only accepted if the
crank angle position of the first image was at -l to 1 degrees (from TDC). All data

acquired with MTV were at 340 RPM and 35 engine cycles of each case.

The following forcing cases were acquired with the MTV method:

Table 2: Forcing Conditions Examined with MTV

 

 

 

 

 

 

 

 

 

 

 

 

 

2m ”$3130"
340 1.00 20, 30, 40, 50, 0—180
60
340 0.35 40, 60 0-180
340 0.35, 1.00 40, 60 40-180
340 0.35 40, 60, 90 0-18, 0-60
340 1.00 40, 60 0-18, 0-60
2.4 MTV Data Reduction

 

The MTV data consisting of pairs of images of original laser grid lines and distorted grid
lines (see Figure 3b) were reduced to instantaneous velocity fields with the process devel-
oped by Gendrich and Koochesfahani [1]. This process correlates Specified source

regions of the original image with roam regions of the distorted image to determine the

16

displacement with sub-pixel accuracy. To achieve a high correlation, the source region
should have distinctive patterns present that are unique within the roam region, such as a
laser grid intersection. This requires that the delay time between the cameras be short
enough that the laser intersections don’t displace to the location where a different inter-
section was originally located. In this experiment, the intersections were 45 to 50 pixels
apart, and the maximum pixel displacements were near 10 to 12 pixels.

The coordinate system used for the velocity fields had it origin, 0, at the top and center

of the cylinder, see below in Figure 3c:

 

41mm

Ax = 4mm

_ _ (i=12._i=0)
(x—~12. y—22) —.l r—(xflm

0:0. j=0) '

l_
T—

 

(i:0.j=16)
(x=-12.

 

 

(i=12,j=16)
(x:40,

   

Xi: iAx - 12 (mm)
Yj :jAy + 22 (mm)

Position Vector: L = X! + yj + 2K

Velocity Vector: X = ui + vj + wk

 

Figure 3c. Coordinate System and Data Locations within the Cylinder

 

 

 

17

The original velocity vectors had an irregular grid spacing that averaged 4.6 mm, and
were re-mapped on a regular grid of 4mm by 4 mm within the region of the non-regular
data by using linear interpolation. The range over which data were collected was from —
16 mm S x S 40 mm or from - 12 mm S x S 40 mm (depending on the data set), and from
22 mm S y S 86 mm. Data at x=40 mm was linearly interpolated from velocity data at
x=36mm and the wall boundary condition at x=41mm. Different variables were calcu-

lated by approximating integrals as summations at these discrete points.

Ensemble averaging of data at common crank angle positions was carried out in the fol-

lowing manner. At a given crank angle position, a flow variable of interest at the kth

engine cycle , ‘I’k, can be represented by:

Wk=fi+w, k

ll
2

(2.1)

where T is the mean value at the given crank angle position, and T’k is the fluctuating

component of the variable at the kth engine cycle. The mean of ‘l’ for N engine cycles is

given by:

N
— 1
‘11 = NE: (wk) (2.2)

The root mean square of the fluctuating component of ‘I’ is:

~ 1 N 2 1 N _ 2
‘I’ = fim 201m 1 = fir: 2013,41!) J (2.3)

=1 k=1

 

 

18

Equation 2.3 would require a data set to examined twice to calculate the RMS compo-
nent, because knowledge of the mean is required before equation 2.3 can be evaluated.
For computational purposes, an RMS expression was sought that would require a single
evaluation of a data set. By expanding equation 2.3, and noting the mean of the fluctuat-

ing component (TH) = 0, yields:

 

 

 

 

q; = Jfi-twf = jfipmwm . HAW—2W?) = jfipfifl

O
(2.4)

and re—expressing mean quantities in equation 2.4 as a summation as defined in equation

2.2 yields:

 

11—1—11)

Thus, equation 2.5 requires only one evaluation of a data set to calculate the mean and the
mean of the squares of ‘I’k for the RMS calculation. From the 35 instantaneous velocity
fields, the mean and the RMS values of the vorticity, circulation, kinetic energy, and tum-
ble ratio were calculated.

The z-component of vorticity at the spacial location (xi=i°Ax-.012, yj=j°Ay-.022) is:

8v Bu V(i+ l,j) V(i—l.j)) (“(i,j+ 1) “(:3 14)) i=0 to 12,
(I) . . = ——— = —— _— _ _ .
( Z)“ ax By ( 2Ax 2Ax 2Ay 2Ay 1:01016 (2'6)

 

The gradients in the vorticity were calculated, as shown, from a first order finite differ-

ence method. The i and j indices represent the x and y grid locations of the vorticity, so

19
each (i,j) pair represents a single point in the grid of data (i.e. a)” = (0(xi, yj), where
xi=i°Ax-0.012 and yj=j°Ay—0.022, See Figure 3c). The AA term is the differential area or

sub—division of the regular grid of 4mm by 4mm, so dA = Ax0Ay = 16 mmz. The circula-

tion could then be calculated as follows:

' I ' : F: (0 dAzAA (D- .. i=3t010,
Omaha“ if z) ,2} “)U {j=lt015 (2.7)

Ensemble averaging the circulation from multiple engine cycles leads to mean and the

RMS components of circulation, which were calculated from the relations:

W rfiir, r=j[{N2r§]_(fi’f_. 1%)] (2.8)

k=l

 

where N is the number of engine cycles, and k refers to the kth cycle in the average.

The kinetic energy per unit mass in its general form is:

 

2 2
Ext-(ll +1) )Ij
. . ij I=3 IO 10,
mm ms: H] (21. +12 )dv~ ’_ . ' 2 jzlmls (2.9)
V ”max—1min). “max—(min

The dV term is the differential volume, where dV = AA(21txi) = AxAy(21rxi), and V is the
total volume enclosed by the data, and V = H(TCR2) = [(jmax - jmin)Ay][1t((imax -

imin)Ax)2)]. The ratio of dV/(2V) is therefore xi/[Omax — jmin)(imax - 1

.min)]'

20

The cycle averaged mean and RMS components of the kinetic energy were calculated as

 

follows:

Mea RM N ..

Wits}; KE— - NXKEk KE: t/[[1% szEk]— (N_—l KE —)] (2.10)
Nk=1

where again, N is the number of engine cycles, and k refers to the kth cycle in the average.

The tumble ratio for the x-y plane is the z-component of the angular momentum per unit

mass of the flow, HZ, divided by the moment of inertia of the fluid about the z-axis, In,

normalized by the angular speed of the crank shaft, 9. It is developed as follows:

 

- 12.9 (2.11)

The angular Speed of the crank shaft is Q = 21c(RPM)/60, and the z-components of the

angular momentum per unit mass, HZ, and moment of inertia, 122, are defined as:

W Hz=l11r><¥)"£)dvzz“i/|X"5 It] dV (2.12)

where L is the unit vector in the z-direction. Expanding the expression r x y in the angu-

lar momentum, HZ. yields:
[txxl'k = [ (Xi+yj+ZL) ><(UI+V1'+WK)] 'k= XV -yu (2.13)

and evaluating the cross product in the moment of inertia, In yields:

I; x [£12 = 1(xi + yj + 23) X L12 = I-yi + leZ = x2 + y2 (2.14)

21

Taking the results of equations 2.13 and 2.14, equation 2.12 can be re-written as

Angular Momentum, Hz 2 2
Moment ofInertia 122 ”Z = I(xv—yu)dV 1;: = 10‘ +,)’ )dV (2°15)
V V

 

Now the tumble ratio from equation 2.1 1 can be re-expressed in a summation form as fol—

lows:

jtxv-yuwv gum, j+(yj)u,. j}
litmus T — V ~41 ’ ' {Show (216)
. 2— ~ '= ~
m Q-jtx’+y’>dv a-Zttx.)’+<yj>’} 11”"
v 131'

 

In equation 2.16, the (2 term refers to the angular Speed of the crank shaft as in equation

2.1 1. The differential volume, dV = (21rxi)AA = (21txi)AxAy, appears in the cancels from

the numerator and denominator.

With the definition of T2 from equation 2.16, the tumble ratio was ensemble averaged

over N engine cycles to calculate mean and RMS expressions as shown in equation 2.17:

 

N N
MeaILanIIJLMS. — ~ -
erplg gggig. T2 = A17 2 (Tz)k T2 = (/[[1% 2 (TZ):]—(N_A-I 1 .TZZD (2.17)
k=1

k=l

2.4.1 Optical Distortions - Correction Method 1

The curvature of the cylinder causes distortion of the images; the distortion becomes pro-
gressively larger towards the cylinder’s edge. To measure the distortion, a target with a

printed grid of 1 mm spacing was placed inside the cylinder before the image acquisition

22

took place. This allowed for a mapping from pixel locations to actual locations within
the cylinder. The mapping of the target lines to pixel locations was done by locating the
pixel location for the peak intensity at each target line within integer pixel accuracy. In
the y-direction, the pixel per mm ratio was found to vary by less than one pixel/mm, so it

was assumed to be constant. The x-direction had a non-linear relationship, see Figure

4C.

i) Calculate the x and y pixel displacements
for a given region of interest in the
optically distorted images

 

 

Same region of

 

Region of

_ . interest which
interest in the has displaced by
image from the some amount.
first camera. A As seen by the A’
(images are second camera
optically distorted) some time, At later.
(also distorted)

 

 

 

 

 

 

 

   
  
 

 

 

 

 

 

 

A B
ii) Convert x and )1 pixel displacements Pixel location to spacial location is assumed
to millimeters which corrects for optical ‘0 be é constant for méy-dfrectlon. and_a
distortion, then calculate velocities. non-linear function which 18 measured in the
x-direction
45 - . SS X-Displacement of point A in mm
40 ~
25 —— N0 Distortion ,
A St) ~—' Measured Location WV a. - — —————
‘ o
E 25 ff»)? '5 I
s: 20 ’ same 3
.215~ <::>_3-— —___ |
‘5 10 * m |
3 5 ' '; Displacement of
O , o .
.fl _5 . . . E porntAin pixels ll
2. -10 » Largest pixel location I
>< 33 / of a grid intersection 1 1 >
is 'L A . . -2 - - - X-Pixel Location A A,
‘ 0 50 100 150 200 250 300 350 400 450 500 550
Original Pixel Location u : (x—displacement)/ At
v = (y-pixel displacement) / (pixel/mm ratio) / At
C D

Figure 4. The methodology for converting pixel displacements to velocity components
(Method 1)

 

 

 

23

In this method of correcting for the distortion, first the instantaneous x and y displace—
ments from a pair of distorted inmges is measured in pixels, see Figure 4 A,B. Next the
two pixel locations corresponding to a displacement are converted to spacial locations
through the pixel to spacial mapping (Figure 4C,D), which corrects for the cylinders dis-
tortion. The two spacial locations are then used to calculate a new displacement and

velocity. This correction method was used for the data presented in the Results section.

2.4.2 Optical Distortions - Correction Method 2

Another distortion correction approach would be to first re-map the images themselves
into undistorted images. Pixel displacements calculated from the pairs of undistorted
images could then be converted directly to millimeters with a constant pixel to millimeter
ratio, see Figure 5. This approach would produce more accuracy, since the sub-pixel dis-
placement calculations would not be affected by the intensity variations from the optical
distortions. The downside to this approach is the increased computational time to redis-
tribute the intensities of each image in a way that conserves the total intensity present and

removes the cylinders optical distortion.

Since the optical distortion does not change the amount of light in the image, the total
intensity contained within a distorted image should be the same as its corresponding cor-
rected image after the re-mapping has be done. In the case of the cylinder’s distortion,
the distorted image is compressed in the x-direction, so during its re-mapping process,
the total intensity of the image will be redistributed over a larger area (since the width of

the corrected image will be larger). So the re—mapping process of the images will

24

 

 

 

 

35 ~ - M%£iisrtgd1Lod]cation 3’"

\I

      

Largest radial location

of a grid intersection
Largest pixel location 5
eqn: y= a*sinh(bx) + c,

of a grid intersection
a=0.0 148, b=-0.l 58, c=8 .67

Pixels/mm
Ch

  
  

X—Axis Location (mm)
C LII

 

 

 

 

 

 

 

 

4
0 50 100 150 200 250 300 350 400 450 500 550 0 10 20 30
A) Oiiginal Pixel Location B) X-Axis Location

i) measure the pixel to actual location in the cylinder. This provides a direct pixel to spacial mapping, and its
derivative provides a pixel/mm relationship across the radius of the cylinder.

 

 

 

 

 

 

 

.. . 550 p
ll) Calculate the pixel 500 for"
re-mapping required to ‘ N9 Distortion . .1",
correct for the distortion. 5 450 ° Distortion M apping °
The re-mapped pixel val- 33 400 A
ues are calculated from a E 350 E
constant pixel per mm .2 300 §
ratio and the pixels spa— .3 250 :5
cial locations in Figure 3 200 ‘2'
A' E 150 V Largest pixel location
. g 100 of a grid intersection
The line labeled “N0
Distortion" is a one-to- 50 My!
one mapping that WOUId 00 50 100 150 200 250 300 350 400 450 500 550

occur if there were no C)

optical distortions. Original Pixel Lo cation (distorted)

iii) Re-map the pixel locations of original
images based on the function in Figure C,
resulting in an image which closely appear
as if it were acquired without the cylinder
present. See Figure D for an example pair
of images. (Total intensity in the image is
not held constant when re-mapped, in this
case.)

'23-.
it 7

1

5
d.
"g!
I.
t

,.
~54ro¢ ‘ s
on V

,...
r.A-'-O 4.".

“VF-6*" ‘.i.

‘0‘"*~.g .. 3.

WC’I1C—tA :1 '

mica ~x. t. , ..,.
- .

The resulting pixel displacements and the
delay time between the cameras, are then
used to calculate velocity D)

 

Original Image Image Corrected for
Optical Distortions

Figure 5. Method for Distortion Correction by Correcting the Images Directly (Method 2).
AB) Optical distortion present in the images due to the curvature of the cylinder.
C) Re-mapping function used to adjust for the optical distortions.
D) An example of a distorted and a corrected image.

25

decrease the signal to noise ratio of the images, which would introduce some new error

into their displacement calculations.

A comparison of these methods was done at a crank angle of 120 degrees, f = 60 Hz, A =
0.35 mm, and A = 0-18 crank angle degrees, see Table 3 for a summary of the results. In
this comparison the re-mapping did not conserve the total amount of intensity. The re-
mapping would first relocate the intensities of two adjacent pixels from the distorted
image to new locations in the corrected image, based on Figure 5a. Next, if the two new
pixel locations were not adjacent, then their intensities were used to linearly interpolate
for any intermediate pixel location intensity values. Figure 5d shows a distorted image
and its corresponding image which has been corrected in this manner. By not conserving
the total intensity in the corrected image, the signal to noise ratio was not changed, so it is

not a factor in the results in Table 3.

Table 3: Comparison of Cylinder Distortion Correction Techniques
(% Change from Method 1 to Method 2)

 

 

 

 

 

 

 

 

Parameter % Change* in Mean Value % Change* in RMS Value
Circulation 0.955 5.61
Tumble Ratio -4.31 -4.83
Kinetic Energy 8.42 9.72
Minimum Vorticity -1.07 -
Maximum Vorticity -6.8O -

 

 

 

* % Change = 100 x (Parametermcthod 1) - ParameterwethodzplParametenMcthodl)

The results in Table 3 show a fairly small change in mean values of the given parameters,

 

26

a larger change in the RMS values. This would be expected since the distortion is only
significant at the edge of the cylinder, and effects only a small portion of the data set. As
a result, the use of the Method 1 for the correction of the optical distortion from the cylin-

der was seen as an approach with acceptable results

Chapter 3

RESULTS AND DISCUSSION

The organization of the flow visualization and MTV experiments was done in a way to
attempt to isolate the effects, if any, of the valve forcing parameters on the development
of the flow. The valve excitation parameters were the peak to peak amplitude(A), the
excitation frequency(f), and the duration of the intake stroke when the excitation is
active(A). Flow visualization was performed at two speeds, 170 and 340 RPM, but the
main focus was on the 340 RPM speed because it is closer to a true operating engine
speed. The only discussion of 170 RPM flow visualization data will be contained in §3.1

to demonstrate some of the flow features observed in the flow visualization.

The intake stroke was the focus of the study (i.e. CA range of 0—180 degrees), but in some
of the flow visualization data sets, data are shown through 210 degrees (referenced to
TDC of intake). This was done since there was interest in the resulting flow Structures at
the end of the stroke, and very little linear piston displacement has occurred between 180
and 210 degrees, so it is similar to the beginning of the compression stroke, even though
the valve is open. The MTV data sets cover the intake range of 90-180 crank angle

degrees, which focuses on the end of the intake stroke as well.

Due to the number of pages of images and plots referred to in the results sections, the
flow visualization figures will be located at the end of the flow visualization discussion

(after section §3.1.3 Effects of the Duration of the Excitation - Flow Visualization), and

27

28

the MTV figures will be located after the CONCLUSIONS in Chapter 4 (Figures start on

page 57).

3.1 Flow Visualization Results

In general, the main feature that could be observed to change in the flow was the size and
strength of the main vortex, especially near the end of the stroke, which was used as the
main qualitative comparator between the various forcing cases. However, other charac—
teristics were noticed when the flow was excited. One flow feature which was greatly
changed was the inclination angle of the intake annular jet as it entered the cylinder. In
comparing Figure 6A and 63 at 170 RPM, the change in the inclination angle of the
intake annular jet can be observed with the excitation of: f = 40 Hz, A = 1.00 mm, and A
= 0—180 degrees. Initially, at CA 2 30 degrees, the inclination angle is smaller (if mea-
sured from the horizontal), and later becomes larger compared to the unperturbed case at
CA = 60 degrees. Another flow feature observed was the near absence of large scale for-
mations in the flow, as seen in Figure 6C, but that occurred at only one combination of
excitation conditions (f = 60 Hz, A = 1.00 mm, and A = 0—180 degrees). It is possible the
flow has became very three dimensional in this case and may have large scale motions in

the swirl plane, but it is not certain if that is true.

The effects of the forcing parameters (Amplitude, Frequency, and Duration) on the devel-
opment of the large main vortex at an engine speed of 340 RPM are described in detail in

the next three sections (§3.1.1 through §3.1.3).

29

3.1.1 Amplitude effects - Flow Visualization

The amplitudes used were 0.35 mm, 0.50, and 1.00 mm. Since 0.35 mm was the smallest
reliable amplitude produced with the valve-shaker apparatus, it was hoped that this would
be small enough to have no effect on the bulk flow so that gradual changes in the bulk
flow could be observed with increasing amplitude. See Figures 7, 8, and 9 for the effect
of amplitude and frequency at CA = 180 degrees. The amplitudes of 0.35 mm and 1.00
mm intensified the main vortex formation when excited at 30, 40 and 60 Hz for many of

the cases, see Figures 7, 8, and 9, so the minimum amplitude threshold was never found.

In Figure 7 (A=O-180), comparing amplitude effects, the amplitude of 0.35 mm appears
to have higher vorticity levels at all forcing frequencies, with the possible exception of 50
Hz, which in either case is similar to that of no excitation. The same tends are also seen
in Figures 8 (A=0-60) and 9 (A=0-18). Some exceptions to this trend can be seen in Fig-
ures 8b,h (20 Hz) and Figures 9d,j (40 Hz), where A=1.00mm appears to be causing more
large scale motions than A: 0.35mm. In most cases though, A=0.35mm appears to have

amplified the large scale motions more than the amplitude of 1.00 mm.

Figures 11 (A=0.35mm) and 12 (A=l.00mm), show the amplitude effect through the
entire intake stroke with f=40Hz and A=0-180 degrees. When comparing these in the
early part of the intake stroke (CA240-80 degrees), the large scale vortices appear stron-
ger with the lower amplitude (Figure 11), but they also are also about the same as the
unperturbed case in Figure 10. When comparing these in the later part of the intake

stroke (CA:150-200 degrees), the 0.35mm amplitude (Figure 11) is much stronger than

30

both the 1.00mm amplitude (Figure 12) and the natural case (Figure 10).
The forcing configurations of:

i) A=1 .0mm,f=30Hz, A=0-180 degrees (Figure 7i),

ii) A=0.35mm, f=60Hz, A=0-60 degrees (Figure 8f), and

iii) A=0.35mm, f=60Hz, A=0-18 degrees (Figure 9f)
had the most favorable effects on the formation of large vortex structures in the tumble
plane. These three best cases Show that the smallest and largest amplitudes chosen have
an effect on the development of the turbulence, and the smallest amplitude has just as
much if not more of an effect at later crank angles than the largest amplitude. Part of this
could be due to the oscillating valve motion generating a circulation pattern in the oppo-
site directions that the intake flow causes, and this effect starts to counteract the benefits
of the pertubation at the large amplitudes. This is supported by the case of 170 RPM,
f=60Hz, A=l.00mm, and A=0-180 degrees greatly attenuated the large scale motions
(Figure 6C), and this was the case of the maximum amplitude at its maximum frequency,
which would cause the strongest opposing recirculation pattern. The same effect can be
seen to some degree at 340 RPM with f=6OHz, A=l.00mm, and A=O-180 in Figure 13

from CA: 20-60.

The 0.50 mm amplitude was excluded from the MTV analysis of the flow. Since the min-
imum required amplitude to create substantial changes in the bulk flow had not been
found, it was decided for MTV to only analyze the smallest and largest amplitudes (0.35
and 1.00mm) with MTV Since the flow visualization results Showed the most amplifica-

tion of the large vortex formations.

31

3.1.2 Frequency Effects - Flow Visualization

Varying the frequency in 10 Hz increments had an effect on the flow in each case to some
minor degree at least, see Figures 7, 8, and 9. The preferred forcing frequencies seemed
to be at 30 or 40 Hz and 60 Hz. The most dramatic results came at these frequencies, but
not at all amplitudes or durations of excitation. Comparing Figures 12, and 13 show an
attenuation effect of the vorticity during 130 to 180 degrees crank angle, when the fre-
quency changed from 40 Hz to 60 Hz (A: 1 .00mm, A=0—180 degrees). On the other hand,
comparing Figures 14 and 15 show an amplification of vorticity when the frequency
changed from 40 Hz to 60 Hz (A=0.35 mm, A=0-18 degrees). Figures 15 and 16 are two
examples at 60 Hz, which were two of the best cases observed. These Show that through
the entire intake stroke, the main vortex formation is more concentrated and localized
versus a larger and less intense vortex when no excitation is applied (Figure 10). Since
60 Hz was the maximum frequency that could be produced at an amplitude of 1.00 mm,
the frequencies of 40 and 60 Hz were chosen the main focus in the MTV data to be

ensemble averaged and compared to the natural case.

It should also be noted that a Strouhal number (StD=fD/U) for the piston-cylinder config-

uration could be based on the mean velocity of the flow through the intake valve opening,
the diameter of the intake valve and the forcing frequency. The mean velocity of the flow
through the intake valve opening varies with the speed of the piston which is a function of

the crank angle, SO StD would also vary as a function of crank angle. So if a constant StD

was desired, the forcing frequency would have to change as a function of the crank angle

in a sinusoidal fashion (f oc U; U oc sin( CA )). The result of Tang and KO [2] with the

32

maximum turbulence amplification of an excited coaxial jet occurring at StD = 1.16,
could be applied to the piston-cylinder geometry by approximated by applying a varying
forcing frequency which starts the stroke at 0 Hz, reaches a maximum value of 36.3 Hz at

90 degrees, and goes back to 0 at 180 degrees. The diagram to describe this is shown

below:

Forcing Frequency, f

Mean Velocity Through
the Intake Valve, U

Resulting StD

 

 

 

I F» CA
0 90 180

Data was not taken for any of those forcing frequency strategies, but it could provide

more insight to the best approach for a forcing frequency condition.

3.1.3 Duration of Excitation - Flow Visualization

The duration of the intake stroke during which the excitation was active, A, had values of
0-180, 0-60, 0-18, 40-180, and 40—180 degrees. The 0-180 degree excitation was initially
examined, and produced some of the strongest appearing turbulence near the end of the
stroke. Exciting from 40-180 degrees had some similar results, but not as strong as the O-
180 degree results. Therefore, the exclusion of the excitation in the early portion of the
stroke seemed to have a lesser effect on the vortex amplification. The question of how
much does the early potion of the cycle affect the flow structures at the end of the stroke

was investigated by looking at A = 0-18 and 0-60 degrees. With A of 0-18 and 0-60

33

degrees, A=0.35mm, and f=60Hz (Figures 8f, 9f, 15 and 16), had substzmtially larger
tumble oriented vortex activity with the appearance of much more mixing occurring at
the end of the stroke than any of the other durations. The same appeared but at lesser
degrees when the amplitude was changed to 1.00 mm, or if the frequency was changed to
40 Hz. This shows that the excitation does not need to be on all of the time for the best

results.

These results from varying A demonstrate that the early formations of the flow entering
the cylinder have long term effects on the development of the large scale structures, and
the results from the excitation during this period do not just dissipate once the excitation

is turned off and the non-excited flow enters the cylinder.

.,,.
‘1..\\;;,..

Ru. .(l 5,! ‘l'
11 mix: v- 75:.) /,'., 'I’-'
{.13} \‘H-lfi‘.

W1 ;l
r I”?

 

Crank Angle: l 10

A) No Excitation 13) f= 40 HZ, A = 1-00 mm, C) f: 60 Hz, A = 1.00 mm,
A=0-l80deg A=0-180deg

Figure 6. Flow Visualization at 170 RPM. (Note the change in the inclination angle at 40 Hz,
and the lack of the formation of large scale structures at 60 Hz)

35

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38

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Flow Visualization with No Exci

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Figure 11. Flow Visualization with Excitation Conditions
f: 40 Hz A: 0.35 mm A: 0-180 degrees

40

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Figure 12. Flow Visualization with Excitation Conditions:
f: 40 Hz A: 1.00 mm A: 0-180 degrees

41

 

Figure 13. Flow Visualization ExcitationConditions:
f: 60 Hz A: 1.00 mm A: 0—180 degrees

42

CA: 191)

 

Figure 14. Flow Visualization Excitation Conditions:
f: 40 Hz A: 0.35 mm A: 0—18 degrees

43

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Figure 15. Flow Visualization with Excitation Conditions:
f: 60 Hz A: 0.35 mm A: 0-18 degrees

CAEIISI) ' : ‘ CA: 300 .

 

Figure 16. Flow Visualization with Excitation Conditions:
f: 60 Hz A: 0.35 mm A: 0-60 degrees

45

3.2 MTV Results

The MTV data were taken for 35 engine cycles of each forcing case. The image acquisi-
tion rate (frames/sec) and the crank angle rate (crank angles/sec) were an integer ratio of
each other, but not phase locked with each other, so each crank angle was not sampled 35
times. The two rates would eventually become out of synchronization, resulting in some
crank angle positions being skipped within in an engine cycle of data. The data were
ensemble averaged at 10 degree increments from 90 to 180 degrees. The sample size was
increased by allowing data to be averaged if it was within i1 degree from the intended
crank angle. This generated sample sizes which varied from 15 to 34 and on average was
25. The parameters calculated from the MTV data were the peak (maximum and mini-
mum) vorticity levels, and the mean and RMS of the following: average vorticity, circula-
tion, kinetic energy, and tumble ratio. In the region of the cylinder which the MTV data
was taken, the main vortex region has a negative sign of vorticity. This means that a more
negative value of circulation, average vorticity, or minimum vorticity indicates a favor-

able condition.

A discussion of the cycle averaged velocity and vorticity fields is done to compare the
MTV results to the flow visualization results. For the examination of the effects of the
forcing parameters (A, f, and A) the mean values of the circulation and the kinetic energy
are used for the main comparators, and for easier comparison, the percent change in these
parameters are looked at in detail. The other parameters which were calculated are found
in Appendix C. Also, note that the MTV figures will be grouped after CONCLUSIONS

section.

46

3.2.1 Cycle Averaged Velocity and Vorticity Fields

The cycle averaged velocity and vorticity fields corresponding to the flow visualization in
Figures 10 through 16 can be found in Figures 17 through 23. All of the vorticity con-
tours are plotted on the same scale from -l20 sec" to 120 sec", and the velocity vectors,
which are on a 4mm by 4mm grid, all have the same length scale, so a visual comparison
between Figures 17 through 23 is valid. The main vortex in the field of view in these fig-
ures has a negative sign of vorticity, so a more negative value indicates an increase in the

vorticity.

When comparing Figure 17 (no excitation) and Figure 18 (A=l .00mm,]E40Hz, and A=0-
180 degrees) over the range of CA=90-110 degrees, the annular intake jet’s inclination
angle is observed to be much steeper for the forced case. The forced case in Figure 18
has higher velocities and vorticity levels, than the natural case in Figure 17, and this
could be due to the forced annular jet not loosing as much of its momentum from imping-
ing on the cylinder wall because of its steeper inclination angle. Another feature in the
forced case (Figure 18) is the center of the main vortex is approximately 4 mm closer to
the center of the cylinder as compared to the unperturbed case (Figure 17). Through out
the rest of the cycle, higher levels of vorticity can be seen at the core of the main vortex in

the forced case.

In Figures 18 and 19, the amplitude changes from 0.35mm to 1.00mm, with f=40Hz and
A=0-180 degrees. The amplitude of 1.00mm (Figure 19) shows higher vorticity over a

larger region of space within the cylinder, and the inclination angle is steeper at CA=100

[E
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1

 

47

and 110 degrees. This effect of higher vorticity and velocities at 1.00mm was not
observed in the flow visualization results of the same forcing cases in Figures 11 and 12,

which showed the opposite trend for the same forcing conditions.

In Figures 19 and 20, the frequency was changed from 40 Hz to 60 Hz with A=l.00mm
and A=0-180 degrees. Increasing to 60 Hz dramatically reduces the intensity of the vor-
ticity throughout the cycle for this case. The annular intake jet has about the same incli~
nation angle at CA=9O degrees, but the magnitude of the velocity vectors is smaller. The
center of the vortex is approximately at the same radial location, but is about 2 to 3 mm
lower than the 40 Hz case at CA=90 degrees, and at CA=180 degrees, it is about 10 mm
lower. The 60 Hz case of Figure 20 has lower peak vorticity levels than the unperturbed
case shown in Figure 17, while the 40 Hz case (Figure 19) has higher levels. These basi-
cally agree with the flow visualization in Figures 12 and 13, which show an attenuation of

large scale motion at 60 Hz for this case.

Figures 21 through 23 are excited at A=0.35 and have Short excitation durations of A=0-
18 or 0—60 degrees. These have similar results which are large improvements over the
natural case in Figure 17. Figure 23 (A=0.35mm, #60Hz, and A=0-60 degrees) overall is
the weakest of the three, while Figure 21 (A=0.35mm, f=40Hz, and A=0-18 degrees) and
Figure 22 (A=0.35mm, f=60Hz, and A=0-18 degrees) are extremely similar, however,
Figure 21 has slightly higher vorticity levels at CA=180 degrees. These results and the
flow visualization results in Figures 15 and 16 agree very well. However, the case of

A=0.35mm, fi40Hz, and A=0-18 degrees in Figures 14 and 21 do not concur, because

48

the flow visualization does not display much of a change from the unperturbed case,

while the MTV results show a large change.

3.2.2 Effects of the Number of Cycles used to Ensemble Average

To examine the minimum number of cycles necessary for the convergence of the calcu-
lated variables, they were calculated starting with 5 samples and increasing by steps of 5
up to 25 samples, if available. This was done for the natural case and one of the forced
cases, see Figures 24 through 27. The mean quantities of the values changed very little
when the sample size was greater than 5 to 10 engine cycles. The RMS quantities started
to converge after 15 engine cycles. Even though a larger sample size would be preferred
for better accuracy of RMS quantities, the sample sizes used still show some convergence
and should make meaningful comparisons. The scatter in the plots of Figures 24 through
27 is fairly consistent between the natural and excited cases. It was anticipated that the
excited cases would have lower RMS values than the natural case due to the forced flow
expecting to respond in a more consistent way due to the excitation, but that did not

appear to take place.

3.2.3 Mean Circulation and Mean Kinetic Energy Results

Plots of the mean circulation and kinetic energy versus crank angle are shown in
'Figures 28 (A=0.35mm,f=40,60 Hz, A=O- 180, 0-60, 0-18),
1Figure 29 (Same as Fig. 28, except A=l.00mm), and
IFigure 30 (A=l.00mm, fi20,30,40,60 Hz, A=0-180).

The mean kinetic energy drops from CA=90 to l 10 degrees. This is due to the inclination

49

angle of the jet becoming smaller, which causes the annular intake jet to loose more
energy as it impinges more directly into the cylinder wall and decreasing the magnitude
of the velocity vectors. The mean kinetic energy starts to rise after 1 10 degrees because
the upper region of the main vortex is entering the range where data was taken, and once
the entire region of the main vortex is in the range of the data, the kinetic energy starts to
decrease as the crank angle position goes from 140 to 180 degrees. The mean circulation
plots Show the same trends as the mean kinetic energy. Lower values of circulation repre-
sent high negative vorticity, due to the negative Sign of vorticity for the large scale vortex
in the field of view, so note that magnitudes of the mean circulation and kinetic energy

increase at the same crank angles and decrease at the same crank angles.

In Figure 28 a clear grouping can be seen, where the cases with A=0-l80 are similar to
the unperturbed case, and the forcing cases of A=0-60 and 0-18 degrees have a clear

increase in mean kinetic energy and mean circulation (again note that “increase” refers

to an increase in magnitude of these parameters; meaning the circulation has become

 

more negative and the kinetic energy has become more positive). When the amplitude is

increased to 1.00mm, in Figure 29, the grouping observed in Figure 28 is no longer
present, and a wider spread in the data is present. The strongest trend present is an
increase in both the mean circulation and mean kinetic energy for cases with A=0-l8

degrees.

Figure 30 Shows the frequency effect for A=1 .00mm and A=0-l80 degrees. It shows that

40 Hz is the preferred forcing frequency (it generally has the largest magnitude of circu-

50

lation and kinetic energy), while 20 and 30 Hz cause little change and 60 Hz attenuates

the mean circulation and kinetic energy.

3.2.4 Amplitude effects - MTV

The effects of amplitude from the MTV results corresponded to the results from the flow
visualization, where the lowest amplitude had the highest levels of vorticity, see Figures
17, and 21 through 23. However, not all cases examined with the amplitude of 0.35mm
produced higher levels of vorticity. For example, in Figure 19, the case of f=40Hz,
A=0.35 mm, A=0-l80 degrees, the resulting vorticity fields are very Similar to the

unforced case (Figure 17).

The percent change in mean circulation and mean kinetic energy between no excitation
and cases with A=0.35mm is found in Figure 31, and the comparison of no excitation to
cases with A=l.00mm is found in Figure 32. Note that a positive percentage change rep-
resents an imgLrovement for either the mean circulation or the mean kinetic energy. In
Figure 31, the forcing amplitude of 0.35 mm generally increased circulation and kinetic
energy versus no excitation, except for the cases with A=O-l80 which had little change.
In Figure 32 with the forcing amplitude at 1.00mm, increases in these parameters versus
no excitation appear to be dependent upon the other forcing parameters, because of the
large spread in the data. The excitation duration of 0-18 degrees does the most amplifica-

tion of these parameters overall with A=0.35mm.

Figure 33 shows the percent change in mean circulation and kinetic energy when the

51

amplitude is changed from 0.35mm to 1.00mm, and the other forcing parameters are held
constant. Figure 33 confirms that increasing the amplitude to 1.00mm, decreases the
mean circulation and kinetic energy, and the only case which shows an increase is
f=40Hz and A=0-180. Since the smallest amplitude used in this study produced the most
amplification, it is difficult to globally say which amplitude would do this best, but it does
show that a small amount of energy introduced into the flow at the proper conditions will
cause a resonance effect and amplify the disturbance. The best cases for amplification of
circulation and kinetic energy with the amplitude of 0.35 mm had a 30% to 40% increase
in mean circulation and kinetic energy at 180 degrees as compared to the natural case (see

Figure 31).

3.2.5 Frequency Effects - MTV

The percent change in mean circulation and mean kinetic energy were examined at
A=l.00mm and A=O-180 degrees with the following frequencies: 20, 30, 40, and 60 Hz.
The results are displayed in Figure 34, which shows 40 Hz had the larest effect for
increasing kinetic energy and circulation from CA=150-l80 degrees. To examine the
effects of 40 Hz, Figure 35 shows the change between no excitation and forcing cases at
40 Hz. A wide range of amplification is possible with 40 Hz, depending upon the ampli-
tude and duration of the excitation. In general from CA=140—180 degrees, there was an

increase in mean circulation and kinetic energy, which was largest at A=0-18 degrees.

The other forcing frequencies of 20 Hz and 30 Hz, in Figure 34, exhibited little change

from the unperturbed state, while 60 Hz has an attenuation effect. However, other forcing

52

conditions at 60 Hz displayed amplifications as seen in Figure 31. Figure 36 shows the
change of going from no excitation to pertubations that are at 60 Hz. At 60 Hz, a separa-
tion appears in the data where amplifications are only seen in the smaller amplitude and
shorter excitation duration cases, and the other cases with higher amplitudes and longer

durations attenuate the circulation and kinetic energy.

As observed in the flow visualization, increases in vorticity occur when the forcing is
done with the Shortest duration and the frequencies of 40 Hz and 60 Hz. To examine the
differences between 40 Hz and 60 Hz forcing frequencies, Figure 37 displays the percent
change in mean circulation and mean kinetic energy when the forcing frequency is
increased from 40 to 60 Hz. When A=0—18 or A=0.35, the response of the flow seems to
be insensitive to a change from 40 to 60 Hz, but if the amplitude is large (except when

A=0-18), then 60 Hz produces less amplification than 40 Hz.

3.2.6 Duration of Excitation - MTV

The duration of the excitation is the most dominant parameter of the excitation along with
the amplitude. In the comparisons from various excitation durations with the unforced
case in Figures 35 and 36, A=0-180 is consistently attenuates the circulation and kinetic
energy or has little change when compared to the other durations. Looking at CA=150—
180 degrees in Figures 35A and 36A, the mean circulation increases as the duration of the
excitation is reduced. These plots tend to show a trend of the A=0-18 and 0-60 degree
cases having the largest increase in mean circulation, while the A: 0-180 degree forcing

shows much less.

53

Comparing the forcing durations of 0-180 and 0-60 degrees helps to show the attenuation
effect of applying the excitation throughout the entire intake stroke. In Figure 36, a com-
parison of A=0-l80 and 060 degrees duration at 1.00 mm, Show that these two durations
have similar effects through CA=l20-130 degrees, then from CA=140-180 degrees, the
difference between the two grows with the A=O-60 duration increasing at a faster rate in
circulation and kinetic energy. Hence, the amount of amplification for A=0-60 compared

to A=0-180 grows as the crank angle increases beyond 140 degrees.

When compared to the natural case, all of the durations examined had an amplification
effect from 90 to 1 10 degrees, which is probably due to the increased inclination angle of
the annular intake jet causing less energy lost from impinging on the cylinder wall, and
the increased inclination angle relocating the center of the main vortex lower in the cyl-

inder where data was acquired (compare Figures 17 and 23 at CA = 100 degrees).

When comparing the unperturbed case to the forced cases at the end of the intake stoke,
the largest amplification came from the forced cases which were excited for a Short in the
beginning of the stroke (A=O-18). As observed in the flow visualization, the excitation
early in the intake stroke have long term effects on the large scale motions, and excitation

early in the stroke does not just dissipate.

A summary of the percent change in the mean values of the calculated quantities at CA =

180 degrees are listed in Table 4 (Figures listed with an A or B refer to Appendix A or B).

54

Table 4: Percent Change* in Mean Circulation, Mean Tumble Ratio, Mean Kinetic
Energy, and Minimum Vorticity from No Excitation at 180 Degrees Crank Angle

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Freq. Amp. Duration Mean Mean Mean Peak Figure

f A A Circulation Tumble Km“ “”9“” Number(s)

(Hz) (mm) (deg) Ratio Energy (minimum)
20 1.00 0-180 3.1 2.02 5.64 5.1 A2, B2
30 1.00 0-180 - l .1 -26.8 -5.29 13.3 A3, B3
40 1.00 0-180 25.3 -17.1 8.3 44.0 A4, B4, 19
60 1.00 0-180 -17.7 -44.0 -33.5 -11.2 A5, B5, 20
40 0.35 0-180 8.0 9.01 -3.67 0.7 A6, B6, 18
60 0.35 0-180 1 1.1 -23.2 2.23 1.0 A7, B7

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90 0.35 0-18 24.3 17.6 36.0 33.9 A10, B 10
40 1.00 0-18 37.5 3.6 19.3 20.5 A1 1, B11
60 1.00 0-18 30.9 4.75 29.7 20.6 A12, B 12
40 0.35 0-60 28.4 1.73 27.8 20.5 A13, B13
60 0.35 0-60 32.2 5.82 26.5 29.8 A14, B14,

23

90 0.35 0-60 36.9 12.9 23.8 31.0 A15, B15
40 1.00 0-60 28.0 -1.73 21.0 35.2 A16, B16
60 1.00 0-60 25.9 -6.87 8.31 31.4 A17, B17

 

* % Change = 100 x (Parametquxcimd) - Parameterm0 Excitation))/Parameter(NO Excitation)

3.3 Other Parameters that could be Examined and Applications

A study of the details near the flow as it enters the cylinder would be useful in trying to

understand the causes for the changes observed in the flow structures when it is excited.

Various pertubation strategies could also be used to further examine the effects of A, f,

and A. For example, the forcing frequency could be sinusoidal; starting at TDC at OHz

 

55

progressing to a maximum frequency at mid-stoke, and then decreasing back to O at BDC

to maintain a constant StD based on the mean flow entering through the intake valve (see

§3.1.2). Another pertubation strategy could have the amplitude gradually decrease
throughout the intake stroke to reduce the counteracting circulation patters generated by
the motion of the valve. A further examination of smaller amplitudes and other excitation
durations, not done in this study, could also give more insight into the effects of the exci-
tation. The interactions between two excited intake annular jets from a four valve config-

uration would be another complex aspect that could be studied.

It is also important to note that this study focused on one engine speed, so that is an addi-
tional parameter which would change all of the preferred excitation parameters. There—
fore, the application of this technique to an operating engine would require a calibration
to map the optimum forcing parameters versus speed and load for the engine. In applying
an excitation in an operational engine, the method of using the valve to excite the flow
may not be practical. It would require a complicated redesign of the valve train (cams,
rocker arms, etc...) to implement, which could have wear problems, and a host of other
issues. However, the implementation of the excitation could be introduced in a number
of different ways, such as acoustically in the intake manifold runners. As a result, these
issues are not seen as unfeasible. Steady state fuel consumption and power output under
firing conditions could then be used to directly compare between the natural and per-
turbed engine configurations, leading directly to the applicability of excited flows to

internal combustion engines.

Chapter 4

CONCLUSIONS

1. The objective of this study was to examine the effects of introducing disturbances in to
the flow of a piston-cylinder arrangement with the emphasis on flow features that might
enhance combustion in an internal combustion engine. It was detemiined that the intro-
duction of small disturbances increase the peak vorticity levels, circulation, and tumble

ratio, with the overall best case increasing the mean circulation 43% at CA=180 degrees.

2. The earlier the applied disturbance is terminated, then generally the greater the ampli-
fication of the peak vorticity levels, circulation, and tumble ratio through the end of the
stroke. Specifically looking at amplification of the mean circulation at 180 degrees,
applying the disturbance during the first 18 degrees of the stroke provides up to a 43%
increase, a disturbance over the first 60 degrees provides up to a 32% increase, and apply-

ing disturbances during the first 180 degrees provides up to a 25% increase in circulation.

3. The smaller the peak to peak amplitude, then generally the larger the amplification of
the peak vorticity levels, circulation, and tumble ratio through. For the amplitude of
0.35 mm, was found to increase the mean circulation up to 43% while the amplitude of

1.00 mm increased it up to 28% for the best cases seen.

4. The amount of amplification of the measured parameters as a function of frequency
generally showed the preferred frequency was 40 Hz or a Strouhal Number of 1.19 based

upon the maximum velocity of the flow entering through the valve inlet.

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Crank Angle (Degrees) Crank Angle (Degrees)
E) F)

Figure 26. Effects of the Sample Size of Engine Cycle used for Ensemble Averaging of Peak Vorticity,
Tumble Ratio, and Kinetic Energy Valve Excitation: f = 60 Hz, A = 1.00mm, A = 0-180 degrees

67

 

 

 

 

 

 

 

 

-0.01 - f -
’6
E ‘ s E
“a -002 . l 2 g
E r . E
8
a _ .
,3 0.03
.13:
O A if? :clels
§ '0'04 i 6 13.3%]???
H V Kl (lVL‘lt‘S
& D 25 (,lyclm
-0.05 ‘ ‘ ‘ ‘ ‘ ‘ ‘ *
90 100 110 120 130 140 150 160 170 180
Crank Angle(Degre$)
A)
3 z 1 , e - , - .
g g 1
v -10 ’ a
i2 ‘ " 8 '
.0
g I
> -20 .
E”
a) C .
> A 5Cvclm
-30 (l ‘t._
O V KKK-1103
5 l C] 25(3'cles
a)” 3
2 -40 . A . ‘ A - A .2
90 100 110 1‘1) 130 140 150 160 llO 180
CrankAngle(Degrees)
C)

Figure 27.

RMS ofCirculation<m2/sec)

 

 

 

 

 

0.006 3 ~ ~ -
. I
x 5
r V g 0 ‘
0.(X)4 O V
A
5 O X
x Q A
9 o g A C] o
0.002 A 5 (lvrlm
G X l() ('Vr‘les
A O 15 (31105
A V 2) (‘vcles
U 25 Cycles
0 A A A g A A A
g) 100 110 120 130 140 150 160 170 18)
Clark Ang1e(Denga‘3)
13)
4 w . . . v v r
A 5 C "cles
X ll) ‘wles
3 g 8 3;; §3.1.3.
. . OS
X C] 25 (.{vt'lm I

8
2- i2 3

 

[EX
D COX
m

 

 

RMS of Average Vorficity(1/sec)

A U 8 X
1L 3
A
O A A . . A A
90 100 110 120 130 140 150
CrankAngle(Degrew)
D)

160 170 180

Effects of the Sample Size of Engine Cycle used for Ensemble Averaging of Circulation and
Average Vorticity - Valve Excitationzfz 60 Hz, A = 1.00mm, A = 0-180 degrees

68

(D
O

100 1 O 120 130 140 150 160 17

——-.— NnEchuUnn
----- m H/.()-ll<(ldcg. 1' -0.018
- » «I Hi. (l-Hldcg. “-‘ ‘
- 60 HI. (HR deg.
40 HI. (l-ll'llldcg.
40 Ht. (l—Nldcg.

B _ . . . Mlllle-lfldcg. 0 g!
1 . A 5‘ -0022

A

-0.018

-0.02 -0.02

Illllll'lIlT

'f

 

[zoom t>

-o.022 “/

-o.024 - . ' -. H i . ‘1 i- -' -o.024

1

Mean Circulation, (m‘/sec)

'_<>

0)

-0.026 "

-0.028

-0.026

-0.028

mm (

awo

-0.03 -0.03

-0.032

-0034 .. g D, 41034
1 1 l I g ‘8 I I I

90 100 110 120 130 140 150 160 170 180
Crank Angle (Degrees)

A

(O
O

100 110 120 130 1
8 F I I I

A

0 150 160 170 18%
l I I

om

+ No Excitation D 7_5
, (1”le (l—leldcg. _ . 7
~ 60“], (l—hlldcg. " - g 7
, 60 Hz. ms deg. E -
‘-- 8-- 40m, n-Ixndcg. V. '
-- » ----- 40 m. ()-N)dcg, "O _ _
B ----- 4t) ”1., (HR deg. ' ‘

6.5

\l
IIIIIIIII
. V<ll>

 

5.5

)

4
."

{b

18 ..

“COCO DIV;
4
4b
01

. . i 2
Mean Kinetic Energy, (ma/sec )

>0 4W '
‘9 K1
. 5'
OJ
U1

 

2 l l l l l J l I
90 100 110 120 130 140 150 160 170 188

Crank Angle (Degrees)
B

Figure 28. Mean Circulation and Mean Kinetic Energy for A=0.35 mm, and All Conditions
with f=40 and 60 Hz, A = 0-180, 0-60, and 0-18 degrees

69

 

   
      
      
  
   
    
  
 

 

 

 

v mace—<0

   
 
   

90 100 110 120 130 140 150 1 1
-o.012 - I I 1- I I I (I50 :0 18(30.012
-o.o14 E- “Z ‘ Saxffi‘ffxitg. -o.014
: v 61) H1. (LN) deg.
" . 7. 4' I
'0-016 :- A 1% 2:111. 1112115., A '0-016
: 44) HI, (Nutmeg
-0.018 _- A D 40 H]. (L m deg, -0013
E 0.02 f— -0.02
E I—
V -0.022 -0.022
:5 II...
o :
g -o.024 _— -0-024
-‘-=' -0.026 D -0.026
cg s;
g 0028 l 5- -0.028
003 f— -0.03
-0.032 E— -0 032
-0.034 E— n 0034
3 I I I I I L I
90 100 110 120 130 140 150 160 170 180
Crank Angle (Degrees)
A
90 100 110 120 130 140 150 160 170 113%
8 _ I I 'l' I I I I I 3
E T No EXCIUUUU 5 i 7'5
7 _ v " 2:323:23‘533 a -: 7
: [> to Hz. 0- 1x drg. B" "- E
_ 8 4()Hl,,ll-1Hl)dt'g. r' -_ 6.5
__ All) ”1., (Hi) deg, I
6 _ (3 40H/..0-1x ucg, _: 6
Si; -: 5 5
5 _— ‘ I>_ -: 5
I. '8 -- é 4.5
2 , -. 5

Mean Kinetic Energy, (ml/secz)

 

 

 

t
3 '_- a3
2 , -: 2.5
_ 'A. E
2 : " ':
C $1.5
1 I I I I I 1_l_; 1
90 100 110 120 130 140 150 160 170 1ll0
Crank Angle (Degrees)
B

Figure 29. Mean Circulation and Mean Kinetic Energy for A=1 .00 mm, and All Conditions
withf=40 and 60 Hz, A = 0-180, 0-60, and 0-18 degrees

70

(D
O

100 110 120 130 140 150 160 170 180

 

 

 

 

 

 

: + No Excitation ,.
-0.014 - ....... A ...... 20m ' -0014
: I....v ..... 3“”,
P: v ‘ 'D 41) HI I»
-0.016 _— <> " W" o -0.016
- O- . ;.
g -0.018 E a " '4 <> -0.018
E -0.02 E- v o. _.<> A“ -0.02
g' P . * ” v "
'5 -0.022 ." ‘ » - -0.022
f; , [>1 , 9 .. I .I
'5 -0.024 ' . , A P -0.024
c: , -. _ » A .
”J A I . I ' .» -
2 -0.026 .‘ - v I) -0.026
-0.028 “ -0.028
.. t>
-0.03 '1>‘ -0.03
I I I I I I I l
90 100 110 120 130 140 150 160 170 180
Crank Angle (Degrees)
A
90 100 110 120 130 140 150 160 170 180I
7 _ I I I I I T I I
: + NuExcuauon A 6.5
_ ,. A 20”, ~ --
6 :- ..iIEjI. 13:1; 4,4 6
------ 60Hz T
“A t; .‘D' , = 5.5
8 -‘ V ' v-
..<’ 5 — 5
_ . . A
E _ D 4 V D..-
>'» L. l> ” 4.5
*3 V _<> ' V
2 rs
g ,E 0 3.5
c: 3 "' V - ‘ 3
5 ~ ~ _ * 0 w
2 r A V O I
_ ,0 . 2.5
~ '0
2 - -- 2
: 1.5
1 ' I I I I I 1 I I 1
90 100 110 120 130 140 150 160 170 180
Crank Angle (Degrees)
B

Figure 30. Mean Circulation and Mean Kinetic Energy for f: 20, 30, 40, and 60 Hz, with
A=l .00 mm and, A = 0-180 degrees

9
600

50

40

10

 

I

30 f.‘

20

I

71

100 110
I I

120 130

I
61) Hz. ll-lROdcg.
60 Ht. ll-(ildcg.
(10 Hz. (HR deg,
- 40 HI. (LlfitMeg.
- 40 HI, (l-flldcg.

140 150
I I

0 C35
“on.

0©I>

C]
06:»

» 401114118 deg. OI

<>><= 01

160 170
I I

<>>< TO

 

L—llllllllA

,V

i
..i.
V

l

‘7
‘0.
O

 

Percent Change in Mean Circulation

I
A
O
llII'lllI

 

v
El":
9

, , ‘ [>
,9.

l l l l l l

-10

IIIIIIII

 

 

(D
O

 

Percent Change in Mean Kinetic Energy
00
o

 

400 —1 8

11> __...

V

llllllTTrl'fTrT {Fill-VIII!

100 110 120 130 140 150
Crank Angle (Degrees)

A

110 120 130 140 150
l I I I I

17

L l L l l l
100 110 120 130 140 150
Crank Angle (Degrees)

B

5"; <><1Q

'. A

5

it:

-20

160 170 180

160 170
l I

6” H7, (H80 deg.
60 H7. (l—(ildeg.
60 H1. (HR deg.
...... 40 H7. (lolfilldcg.
------ 4011;..0amcg.
------ 4()H/..0-18 deg.

 

l l
160 170

Figure 31. Percent Changes* in Mean Circulation and Mean Kinetic Energy between
No Excitation to Cases with Forcing Amplitudes of 0.35 mm

* % Change = 100 x (ParameterI0'35 mm) - ParameterIN0 ExciIEIIIOII))/Parameter(N0 Excitation)

72

 

 

 

 

 

 

 

90 100 110 120 130 140 150 160 170 1
7° — A I I I I I I I — 07°
3 E 21543.13“ :
so :— 9 1‘ :1" -: 60
: <> .2 1:113:11; ;
50 I- Q A 8 33311313325 1 5°
8 E E
'5 4o .— v O ‘ 4°
3' - ’ ‘ V . g {D
2 r. 0 »- ,. - -,
5 30 g 9 £230
5 ;' , I) o o 1
g 20 :- ._ .1 v a -_ 20
.E A: B B f/ D E
30 10 §- 9 " A A A -_ 10
5 Ii ‘3 g
I: _
u 0 _ _ o
E : D A D 3
0 ~ _
2 -10 .__ . , -_ -10
a I g [j i
-20 :— D ‘ '-_]-20
3 ' A :
-30 E A D -j -30
: D 3
1. _
.4090 100 110 120 130 140 150 160 170 1ll640
Crank Angle (Degrees)
A
1009() 1&0 110 1%9 180 1110 1?0 1:50 1:0 1:00100
90 - —f 90
I D MHLIqudcg :
80 — .‘ A wnummcg, —: 80
6 V («m/404M“, E
>‘ 70 - I) AOHIJHRUdL-g. -= 70
OD 40H1.(HWdeg. I
5:; 60 7 V .7 I. 8 40HLledcg —; 60
if. 501- ' v -§50
g 40 - -f 40
$2 A g 8 :
5 30 - 3.1 .g' ,1 - 30
E 20p ‘2. ES - 20
I: p 9
~; 10 - W , ,9 O A -I10
5) 0r Q . 9 >0
5 I) V . _
9 -10 :- * O 8 A -: -10
C I ' I
§ -20 - I o . -; -20
3 -30 - " D 5 -30
9 A a a 2
-4o - G @1-40
-50 - - A a -§-50
_ I 1 Ed I L I I = _
609 100 110 120 130 140 150 160 170 1 O60

 

 

Crank Angle (Degrees)
B
Figure 32. Percent Changes* in Mean Circulation and Mean Kinetic Energy between
No Excitation to Cases with Forcing Amplitudes of 1.00 mm

* % Change = 100 x (Parameterum mm) - Parameterm0 EIICIIIIII(III))/Parameter(No EchIaIIOII)

73

 

 

 

 

 

 

 

 

 

90 100 110 120 130 140 150 160 170 180
4° - I I T I I I I I _ 4°
: E NHILIHNUdcg :
30 ; > > ' v 213311132: 5 so
: D 40112101111111“ :
_ El 8 40 In. 060 lit-g. ‘
S 20 h 4llll7qll~llideg I) —. 20
E E ...A D :E>
E 10 C A ’ D D : 10
U C —
g .7 o :
U _
2 0‘1 O O I n 8 2..
I: - ru
-- I C) V Ifia _
E 10 :4 V V O [I fit g C 10
E3 45 <> 0 " 0 :
5 — A ~
2 - A . ‘
:13 -20 _— . g 9 -_ -2o
-30 .. ‘- CI - -30
: E :
_40 " I I J [r L I I ‘ -40
90 100 110 120 130 140 150 160 170 100
Crank Angle (Degrees)
A
90 100 110 120 130 140 150 160 170 110
40 - I I T I I I I I - 40
: I) I: :
3° _- am a 21:13:11.3: 2 3°
g ' v MH/JHXdeg . 71>
g. 20 _- D ::::::::::::‘:.3: D ‘- 2°
2 : A 8 Jillian-{Pith}- E
f 10 E- D -_ 10
.2 0C5. . 0 1V 1 {>1 E 0
M I ~ v ,. V V. -
g £55 8_ 0 -..® 8 e . . . E>
z 40% v 0 ’ <> ' 8 ” ’6'")
.E E 0 I
z _
2° -20 .— 5 o (A -. -2o
5 3 "“9 . :
a -30 :- A -j -30
u _ E} CI -
8 : D . -
E: -40 _- {L40
2 ._ A 2
-50 :- 23 D -: -50
t J I I 1%? 4L 1 1 E
.6090 100 110 120 160 170 113660

Figure 33. Percent Changes* in Mean Circulation and Mean Kinetic Energy
from Increasing the Forcing Amplitude from 0.35 mm to 1.00 mm.

1 30 140
Crank Angle (Degrees)
B

 

* % Change = 100 x (ParameterIIIOO mm) — Parameter(0_35 mm))/Parameter(0'35 mm)

74

 

100 110 120 130 140 150 160 170 180,0

 

 

 

 

 

1 l r l l l l I

V *C} ZOHZ 60

. A 30m
8
'3 ’ 40
'5 30
g V V V """"" ‘ 20
E , '
.s t> V
é t,@._ v 10
.2 -. [:1 I EL .13. D
U U - , ' ‘U- A
E 5 X gy- a-
2 -10 _- A E ' ‘
E : V ”D ,

-3o 9 ‘1 EI»> D
.40 t I I ? I I I I I 7.40
90 100 110 120 130 140 150 160 170 180
Crank Angle (Degrees)
A

100 110 120 130 140 150 160 170 180

100 10°

 

 

 

 

 

Q l l l I l I r

80 D 1:12.111" £33: 80
g, 70 i:':;;:g:;;:ii 13:: 70
g 60 60
f: 50 ' 50
.3 40 40
>4
5 30 __A _ 30
:E 20 ‘ in 20
-; 10 D ; .,g,~ ~r 1o
2 V1 .. .»A'
B -10 A A -V‘ '10
2,; -2o ‘ . . -20
£ _30 “57¢ V -30

V" ‘ . 'D I ......... D

.40 D ....... , '40

-5o 2 _M_.>““‘ -5o

-60 I I ? """ i I I I I 7 -60

100 110 120 130 140 150 160 170 180
Crank Angle (Degrees)
I}

Figure 34. Percent Changes* in Mean Circulation and Mean Kinetic Energy between
No Excitation and 20, 30, 40, and 60 Hz at A=l.00 mm, A=O-180 degrees.

* % Change = 100 X (Parametermt Given Frequency) ‘ Parametermo Excitation))/Parameter(No Excitation)

75

970 100 110 120 130 140 150 160 170

 

        

 

 

 

 

70 I I I I I I I I
60 D C} ----- 0 35 mm, mandcg.
O --A (HSmntJI-lxdcg.
' - ~ .35 mm. c I.
50 8 ’ ». , 3 ~ (l,,(l)mn1_::?:(;jd:g A
s ‘ * ' ' 8 : ::::"‘m-:::::::‘:*'~ e - ..
g 40 ‘ "‘m' ‘ "“’ - A
(3 30 _j g A V
f: A . § _ __ , fjj ......... g
3 20 C] V j g " " O ,. 9 i 1 20
E A _. , .
,E E I K _ f e / 'D 3
5'3 E1 fi_.— 0.. .- I3 . 3
6 0 : '* . V . _ “ ‘3 I 0
E : D _ ‘5 2
8 -10 9 ~ I f... "‘ ’ ' D .1 -10
a“: : g :
-2o :- -j -20
-3o :- -j -30
_40 I 4 I I L I I I ‘ -40
90 100 110 120 130 140 150 160 170 180

Crank Angle (Degrees)
A

 

 

 

 

 

100 110 120 130 140 150 160 170 180
8 I I I I I I I 100
1 .. "B ------ 035 mm. 0480 deg. 90
--A- 0.35 mm.0-18dcg_
I} v_ --v 0.35 mm. (i-Nldcg. 80
{If - A E. ----- D -- H)" mm. (HROdcg.
gs _s. 0, "18 ‘1 ::::n::::::::::: 70
q, . . _ ..
L5 - 60
.2
E D a, 50
>4 _ _. A '
'6 A O 20
E 10 :- 2. . é _;.- O 10
U E g ' V E i>
g o : g i A A i C] ‘ , ‘ _ . . u D ..... D 0
e : _ .
g '10 E' 9 _. f g -10
-20 §- O" -2o
-30 :- _. D -30
_ I J I I I I I I I _
4090 100 1 10 120 130 140 150 160 170 18040
Crank Angle (Degrees)

B

Figure 35. Percent Changes* in Mean Circulation and Mean Kinetic Energy between
No Excitation and Different Excitation Durations at 40 Hz

* % Change = 100 x (Parameter(40 Hz) - ParameterwO EXCitalionp/Parametermo Excitation)

76

 

 

 

 

90 100 110 120 130 140 150 160 170 110]
7° 3 d) I T f r u I I 1 0
6° :- Cl (”SmmJIrlKUdcg _:l 60
: A l) 35 mm. (MK deg :
._ 135mm, 1» D c! .I
50 _'- A O {v} lilllIIIIn.:l-(I)‘Hltlldig 1 50
E Z W 8 lllInImJI-lh‘dcg :
g 40 :- . O llllnlmJLNldtg e A '2 40
a :_ __ , A 8
5 3Q?” 6 V @530
g I: 9 §>
E 20 3' Cl 2 O -: 20
as Q 9 -
30 1o - 8 O 0 £110
5 i; D D ' E
6 o _ D ' A o
E E D D g l> D E
2 -10 _- 1 -10
£ : t> _
-20 :- D 320
E O E
-30 _- O D -_ -3o
: D ‘
_ _ I 1, l L -
4090 100 110 120 130 140 150 160 170 1! 040

 

Crank Angle (Degrees)

 

 

 

 

 

A
9 100 110 120 130 140 150 160 170 1 0

11° W" I 1‘ I I I I I “0

100 - D (lJSnImJI-Ililhkg, - 100

so - 3 Emmi: - 90
a 80 - g g ‘ IIBEEAHSLSE' - 80
E) 70 _ - . lll)mm.(LHIdug _ 70
u.) .. .
.2 60é . _@ 60
g 50 A - so
_ ‘ ,.
g 40 - D .1 9 v » - 40
g so . ‘ A 8 - 30
.5 2°C" v V ->2o
a IoE- § 8 o o -510
g or D __, C] 0
5 5 U B LI 1

D ..

E -10 - 8 - -10
g -20 - - -2o
0-

-30 - O D D -30

-40 - l> - >-40

-50 - a; O l> - -50

-60 I I I? I I I I -60

9 100 110 120 130 140 150 160 170 1 0
Crank Angle (Degrees)
B

Figure 36. Percent Changes* in Mean Circulation and Mean Kinetic Energy between
No Excitation and Cases with Forcing Frequencies of 60 Hz

* % Change = 100 x (Parameterwo Hz) - Parametermo Excitationp/Parametermo Excitation)

77

 

 

 

 

 

 

 

 

 

0 1
209 “:0 1:0 ?0 11:0 1210 1?0 1:50 1:0 18%0
- O U -' (l 35 mm, (Llehk‘g -
_ A II 35 mm, II-Ix III-g. —
_ D . V > 035 mm,[lrh()deg. _
1° ' P liiimtili‘lfl?“ - 1°
8 1: O 6 A 8 Ion mm: (Hi) dc; :
.5 s v _
. . ‘ .4 I3 . -
7; GET ' A A L g ., V I W . ’ V. X ..“0
o <§ g e .g .i a I , 59>
E -' Cl ' a ' ’§>
g Q 0 O _ . .
.5 -1o - D ' 8 O 0 —“-1o
20 I _;O I
E I" ‘
._ . O .—
5: -2o - .g - -20
§ 3 P ., I
,3 _ I> - f> _
-3o - E i -30
_ D > A),
_40 ' I 41 I I I 1__1_I__j‘_40
90 100 110 120 130 140 150 160 170 1110
Crank Angle (Degrees)
A
90 100 110 120 130 140 150 160 170 18
5° 3 I I 1" I I I I I j 930
40 :- C] lHSmmJHflUtkg. a 40
Z A I>,35mm,(I-decg. 3
:_ -' ' .BSmm, - e3. -
3 3° ; o 7% filmmmlli‘lli'da. 3 3°
5 : » 8- l.lllmm.()-llldcp. :
LE} 20 __ llllmm.()‘fl)dqz. _‘ 20
.g : E ___II
8 10 :- <> , , -E 10
'2 1:. O 8 0 v ’ U“ :
z o _ A ...A Q ..... . é" A v — 0
3 ' A . I V K V ' 7
2 [3; Cl A v v . ‘_9
.5 40(2— _ Q U -_ -1o
E’o : , ‘V O :
5 -2o 2.- —‘ -2o
5 <2 ,. O O 2
§ -3o[§- 9 ~ .1 -j -30
E Z " " :
On _ "'- O >_ ,,,,,,, D _: _
-50 j- -: -50
- 3 I I I I I J—L__l_: -
6090 100 110 120 130 140 150 160 170 1 060

 

Crank Angle (Degrees)
B

Figure 37. Percent Changes* in Mean Circulation and Mean Kinetic Energy when
Increasing the Excitation Frequency from 40 Hz to 60 Hz.

* % Change = 100 x (Parameterwo Hz) — Parameter(40 HZ))/Parameter(40 Hz)

APPENDICES

Elam
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12
A13
A14
A15
A16

A17

78

APPENDIX A

Flow Visualization Images at 340 RPM

Excitation Conditions figs;
No Excitation 79
f: 20 Hz A: 1.00 mm A: 0—180 degrees 80
f: 30 Hz A: 1.00 mm A: 0-180 degrees 81
f: 40 Hz A: 1.00 mm A: 0-180 degrees 82
f: 60 Hz A: 1.00 mm A: 0-180 degrees 83
f: 40 Hz A: 0.35 mm A: 0-180 degrees 84
f: 60 Hz A: 0.35 mm A: 0—180 degrees 85
f: 40 Hz A: 0.35 mm A: 0—18 degrees 86
f: 60 Hz A: 0.35 mm A: 0-18 degrees 87
f: 90 Hz A: 0.35 mm A: 0-18 degrees 88
f: 40 Hz A: 1.00 mm A: 0-18 degrees 89
f: 60 Hz A: 1.00 mm A: 0-18 degrees 90
f: 40 Hz A: 0.35 mm A: 0-60 degrees 91
f: 60 Hz A: 0.35 mm A: 0-60 degrees 92
f: 90 Hz A: 0.35 mm A: 0-60 degrees 93
f: 40 Hz A: 1.00 mm A: 0-60 degrees 94
f: 60 Hz A: 1.00 mm A: 0-60 degrees 95

79

n 1 (

n .' Sm”: I . u . milieu-n,

 

Figure A1. No Valve Excitation

80

'- 81)

1M aillw'l ,III-n‘. I-umn

 

Figure A2. f: 20 Hz, A: 1.00mm, A: 0-180 degrees

 

Figure A3. f: 30 Hz, A: 1.00mm, A: 0-180 degrees

82

 

Figure A4. f. 40 Hz, A: 1.00mm, A: 0—180 degrees

83

 

Figure A5. f. 60 Hz, A: 1.00mm, A: 0-180 degrees

84

 

Figure A6. f. 40 Hz, A: 0.35mm, A: 0-180 degrees

85

3‘:

.\~‘. ‘\
I": 1*“\':“

 

Figure A7. f. 60 Hz, A: 0.35mm, A: 0-180 degrees

r.."{

l

86

 

Figure A8. f: 40 Hz, A: 0.35mm, A: 0-18 degrees

87

 

Figure A9. f: 60 Hz, A: 0.35mm, A: 0—18 degrees

88

 

Figure A10. f: 90 Hz, A: 0.35mm, A: 0-18 degrees

89

 

Figure All. f. 40 Hz, A: 1.00mm, A: 0-18 degrees

.
. v

.... :,.,..‘..
C .'

 

Figure A12. f. 60 Hz, A: 1.00mm, A: 0-18 degrees

91

 

Figure A13. f. 40 Hz, A: 0.35mm, A: 0-60 degrees

92

3
1‘
I

'9
w

 

Figure A14. f. 60 Hz, A: 0.35mm, A: 0-60 degrees

93

 

0.35mm, A: 0-60 degrees

Figure A15. f. 90 Hz, A

94

 

Figure A16. f. 40 Hz, A: 1.00mm, A: 0-60 degrees

95

 

: 1.00mm, A: 0-60 degrees

40 Hz, A

Figure A17. f

Figure

B1
B2
B3
B4
B5
B6
B7
B8
B9
BIO
Bll
B12
B13
B14
B15
B16

B17

MTV Ensemble Averaged Velocity Fields at 340 RPM

96

APPENDIX B

Excitation Conditions

No Excitation

f: 20 Hz
f: 30 Hz
f: 40 Hz
f: 60 Hz
f:40 Hz
f: 60 Hz
f. 40 Hz
f: 60 Hz
f: 90 Hz
f: 40 Hz
f: 60 Hz
f:40 Hz
f: 60 Hz
f: 90 Hz
f:40 Hz

f: 60 Hz

A

1.00 mm

21.00mm

:1.00mm

: 1.00 mm

: 0.35 mm

: 0.35 mm

: 0.35 mm

: 0.35 mm

: 0.35 mm

: 1.00 mm

:1.00mm

: 0.35 mm

: 0.35 mm

: 0.35 mm

2100mm

: 1.00 mm

: 0-180 degrees
: 0-180 degrees
: 0-180 degrees
: 0-180 degrees
: 0-180 degrees
: 0-180 degrees
: 0-18 degrees
:0-18 degrees
:0-18 degrees
:0-18 degrees
: 0-18 degrees
:0-60 degrees
:0-60 degrees
: 0—60 degrees
:0-60 degrees

: 0-60 degrees

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

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114

APPENDIX C

Plots of Statistical Quantities from the MTV data

 

flgm T_itl§ Egg
C1 Effects of Frequency on the Average Vorticity 1 15
C2 Effects of Frequency on Circulation 1 16
C3 Effects of Frequency on Kinetic Energy 1 17 3
C4 Effects of Frequency on Peak Vorticity Levels 118 9
C5 Effects of Frequency on Tumble Ratio 119 a;
5
C6 Effects of Amplitude and Excitation Duration on Average Vorticity 120 E"—
C7 Effects of Amplitude and Excitation Duration on Circulation 121
C8 Effects of Amplitude and Excitation Duration on Kinetic Energy 122
C9 Effects of Amplitude and Excitation Duration on Peak Vorticity Levels 123

C10 Effects of Amplitude and Excitation Duration on Tumble Ratio 124

 

115

 

 

 

 

 

 

 

 

 

 

 

 

   

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

g E
a > 8
§- E, 7 HM) Excitauon
.0 'a
E ‘e 6
>° o
E :5
a g
3
g a
o "5 2
§ -40 ‘2 1
2 90 100 110 120 130 140 150 160 170 180 a: 90 100 110 120 130 140 150 160 170 180
Crank Angie (Degrwe) . Crank Angle (Degrees)
A) B)
a g”
£5: 53‘7
.9 .u
~26
in > 5
3 ‘3
«a $2
5 "’ 1
g 90 100 110 120 130 140 150 160 170 180 E 90 100 110 120 130 140 150 160 170 180
CmnkAngle(Degxees) CrmkAlglemqmea)
g C) W’ A ' ' D)
5" g 8
£‘ .é 7
a a
:2 >° 6
q: q, 5
5‘ i ‘
g 4
:5 <3
“5 “a 2
§ -40 m 1
E 90 100 110 120 130 140 150 160 170 180 E 90 100 no 120 130 140 150 160 170 180
Crank Angle (Degrees) Crmk Angle (Dm)
E) Amphmdzfllimllumnanfimdegmm F)

Figure Cl. Effects of Frequency on the Mean and RMS of the Average Vorticity
(Circulation Normalized by Area)

116

 

 

   

 

 

 

 

 

 

 

 

   

 

 

 

 

 

 

 

 

   

 

 

 

 

 

 

001 0.006
9.3 Ni 0.005
E a
.3 g 0.004
a '9:
3 “:4
.g g 0.003
U ‘0'03 .—.N0 l'kcimtian '0
l——I 20m
a V~~730Hz 0,002
2 333811; E
-004 0.001
90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 160 170 180
szkAnglMDegmes) kaAmlMDegma)
A) Amphmdeiflflmmflummfldegmm B)
-0.01 0006
NE NE 0.006
E E
.5 5 0.004
g a
g E 01003
‘3 o
U)
0002
E E
-0.04 0.001
90 100 110 120 130 140 160 160 170 180 90 100 110 120 130 14.0 150 160 170 130
CmnkAiglemegreea) CrmkAngle(Degmes)
C) AmMMeJiimmfiumflMfldzgmm D)
-0.01 0.006
NE “g 0.005
E 002 E
E ' ‘ g 0.004
é" a
1" 0.003
53-0-03 5
V)
g 0.002
2 E
-o.o4 0.001
90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 160 170 180
CrankAngiemegmes) kaAngletDeglea)

E) W F)

Figure C2. Effects of Frequency on Mean and RMS Circulation.

117

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

“A 0.020 4+ . 7 A ~ - «A 0.005
§ 11 HNanciuition §
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.g 3 0.002
5 “a 0.001
g m
20% 50-..-.-.7.
90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 160 170 180
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A) WWW B)
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§ k O—O‘lfgll'llzxcimuoni E K
\ F-V “‘ O—ONO Brcitation
N __ - a _ .
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E y k \\ o——090Hz
[g 1 \ 0.003» \
U
3 ‘5 0.002
g 5
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5 m
o ‘ a
.....7-- 07.4...-..H
90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 160 170 130
Crank Angle (Degrees) Crank Angle (Degrees)
C) Ampbmdefiiimmflumnmmgm D)
«g 0.020 "g 0.006 - . - - . -
N\ "E ‘ O—ONoExcitauon
8 0015 v \ v—-Av40nz
"2’ . \ 13-—E160Hz
g @0004» \ o——0901h
:5 0.010 g 1\\\
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a 0002 \‘1\
'5 0005 - ' ' . k\
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5 (Z -- , g
G) H i
2 o A A A A A A A A A g 0 . A A A A A A A
90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 150 170 130
Crank Angle (Degrea) Crank Angle (Degrees)
E) Wng F)

Figure C3. Effects of Frequency on Kinetic Energy per Unit Mass.

Max Vorticity (Ilsec)

Max, Vorticity ( 1/sec)

Max. Vorficity(1/sec)
8

0
90 100 110 120 130 140 150 160 170 180

118

 

 

 

O—ONoEkcmm'on
I--—l 20H:
F-vfiOHz
a——u 40H:
0— —o 60H:

 

 

 

 

 

 

Min Vorticity (llaec)

Min. Vorticity ( Ilsec)

 

 

 

 

 

100 110 120 130 140 150 160 170 la)
CrankArngDegmes)

 

 

 

 

 

100 110 120 130 140 150 160

CrankAng'le(Degrees)

170 180

C) Amhmdnifimnflumumfllfidegzm

 

 

 

 

75
O—ONofircitation
60L Elmfi
Ki °——°%H1
45 \\
\
30 \
15 a? _ -aA-
0
90 100 110 120 130 140 150 160 170 180
(hankAnglemegrees)
75
HNoI‘kcitmion
v—«vaz
60 §\ o--060Hz
\\ 0“-4K)HZ
\
45 ‘
m
‘ \
30 {\\
\\ _7
15 - ’/ - » a ‘
v’
0
90 100 110 120 130 140 150 160 170 180

Crank Argle (Degrees)

Min Vorticity (Ilsec)

 

 

 

 

 

100 110 120 130 140

150 160 170 180
CrankArclemegrees)

E) WWW“ F)

Figure C4. Effects of Frequency on Peak Vorticity Levels.

 

119

 

 

 

2.0 0_5--7-
O—ONoExcitah‘on
“we
V—-"V-(
1.53~C G—-+:140m
‘Q G——060Pz

Mean Tz

 

 

 

 

 

No Excitation
Hz

 

 

 

0 - . - . - - .
90 100 110 120 130 140 150 160 170 180

0.1 ‘ ‘ ‘ ‘ ‘ ‘ A ‘
90 100 110 120 130 140 150 160 170 180

 

 

 

 

 

 

 

  

 

 

 

Crank Angle (Degrees) Crank Angle (Degrees)
A) Ampflmdeiflanmnflumflanallfiaciegm B)
2.0 77.-..-.-7 05+ -7- A
» O—O No Excitation '\ O———O No Excitation
, v——v4ouz r v—Mvaz
G——5601{z r G--860Hz
1.5k o-—090Hz * 0.4' o———090Hz
. \ a
m
2 0.3
D:
0.2 ‘ y
0 ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ 0.1 ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 160 170 180

Crank Angle (Degrem)

C) W

D)

Crank Argle (Degrees)

 

 

Mean Tz

 

 

 

 

 

1

0—0 No Excitation
9— - ~9 40 Hz

G--E160Hz
o—-—O90Hz

  

 

 

 

O ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ 0.1
90 100 110 120 130 140 150 160 170 180

Crank Argle (Degrees)

E) WW5

Figure C5. Effects of Frequency on Tumble Ratio.

90 100 110 120 130 140 150

F)

Crank Argle (Degrees)

160 170 180

' avail
'-

auan 0

1..“

Mean of the Average Vorticity (Ilsec)

Mean of the Average Vorticity (Ilsec)

Mean of the Average Vorticity(1/sec)

Mean of the Average Vorticity (Ilsec)

120

 

 
       

 

 

A

RMS of the Average Vorticity (Ilsec)

 

 

 

 

 

 

o.
A
-10
ré‘é’r‘
- 7 -—F/' ’
A20 3 a:
O—ONoi-kcium'on
-30 l——I0-180deg
v——v40-180deg
13—41013 drg
~60
-40
90 100 110 120 130 140 150 160 170 180
CrarkAngle(Degre$)
A) F . 40H:
0

 

 

 

 

 

 

 

 

 

 

u

(I)

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RMS of the Average Vorticity(1/sec)
o A

8
Nochrmnon
I--—l 0.180092
er\ s Ei‘é‘fiéfl?‘
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\a / F
4
2
0
90 100 110 120 130 140 150 160 170 180
CrankArgle(Degrees)
" J 035mm )

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 160 170 13°
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90 100 110 120 130 140 150 160 170 180 g 90 100 110 120 130 140 150 160 170 180
Crank Angle (Degrees) Crank Angle (Degree)
E) r 1 1 00mm F)
gs
E O—ONuExciBtffion
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90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 160 170 130
Crank Angle (Degrees) Crank Angie (Degree)
0) I“ . 60Hz ‘ " 1 100mm H)

 

Figure C6. Effects of Amplitude and Excitation Duration on Mean and RMS of the
Avergae Vorticity (Circulation/Area)

Mean Circ ulau'on (m2/ sec)

121

 

 

      

 

 

 

 

 

 

 

 

 

‘2

Mean Circulation (m /sec)

2

Mean Circulation (m /sec)

2

Mean Circulation (m /sec)

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Crank Angle (Degrees) Crank Angle (Degrees)
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-0.04 . A . . A . . A A 0 A A . A
90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 160 170 180
Crank Angie (Degrees) Crmk Angle (Degrees)
C) D)
0, 7 0.008 + A
o—oNo Excitation g
-001 - "E 0.006
E
. 8
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0.02 '3 0.004
.E’
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v——v 40—180deg
E G- - —0 0-18 deg
0— —0 0-60 deg
A004 - A . - - . . 0 A A A A A
90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 160 170 180
Crank Angie (Degrees) (hank Angle (Degrees)
E) W F)
0 . ~ - 0.008 A A -
’g .
{I r
001 ~ “8 0.006 ~
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8
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-0.04 A A A A 7 - A 0 - . - - . - - 7- .
90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 160 170 180
Crank Angle (Degrers) Crank Angle (Degrees)
G) W ' - H)

 

 

 

 

 

    

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure C7. Effects of Amplitude and Excitation Duration on Mean and RMS Circulation.

 

 

0

Mean Kinetic Energy (m’/sec")

"I

')

Mean Kinetic Energy (nf/sec")

‘)

Mean Kinetic Energy (mg/secz)

Mean Kinetic Energy (m2/secz)

122

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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l O———O No Excitation § F—O Ni) l-lxcrtauon
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0.010 CE
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0 ‘ ‘ A ‘ ‘ ‘ * * ‘ m 0 ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 160 170 180
CrankAngle(Degrees) CrankAngle(Degrees)
A) W B)
0020 A A A A A A A A "A 0.006 A A A A A A
{ O—O qufixclimuon § :—: g‘hfg‘fili‘uon
\ l—-—l A‘Jto \ -- . t.-
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0.015 ’ \\ t3 — - a 0-18 (10g v (3 — - a (L18 (lug
k \ 0— —O 0'60 deg 0.004 1 / \ 0— ——0 0-60 deg
. E1
0.010 ’ r3
u‘s’
0.002
0.005 : '
m
90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 160 170 180
Crank Angle (Degrees) Crank Angle (Degrees)
C) F requencrxjo Hz. Amplitude: 0.35 mm D)
0.020 A A 7 A A A A A ..A‘ 0.006 - ' '
H No Fbrcitan‘o § K H No Excitation
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0.010 , ca
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0 - - - - 7 7 . - a 0 - - - - - . - .
90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 160 170 180
Crank Angle (Degrees) Crank Angie (Degrees)
E) EmmmmJQHLAmphmMQmmA ' - F)
0.020 a A A A A A A A A A A NA 0.006 A A A A A A
\ H No Excitation § 5 0—0 No Excitation
‘ ' ' ’ ' 2812813 .\ A ' ' ‘ ' $30.91“
0.015 R; 3,—3.2 0-1‘8 ...:g‘“ . E Q 3‘— —E m"); .13.?“
I. \ \G\ 0— —0 0-60 deg 0.004 . R 0— —0 060 deg
0.010 » E
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is 0.002
0.005 E
9.3
0 ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ g 0 ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 160 170 180
Crank Argle (DegreeS) Crank Argle (Degrees)
G) H)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure C8. Effects of Amplitude and Excitation Duration on Kinetic Energy per Unit Mass.

Max Vorticity (l/sec)

Max. Vorticity ( Usec)

Max. Vorticity ( llaec)

Max. Vorticity (Usec)

q
OI

123

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

-20
No Excitalion
sol :532y1i36keg "‘ 4o
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45 \\ E, -60
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30 E -80 / °’:°\ \o/ffif’a
> ‘ I /p- a“~i3‘ _ ,
.9 ‘ i // .H_-.R'i§3‘§"“‘°"
15 S -100:\ / v——v40-ll"0r
/ a — —El 0-18 [leg
‘\1 o— 60 x
0 -120
90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 160 170 1a)
CrmkAnglemegrees) (hankAngle(Degzeen)
A) Wm B)
75 -20
Harare”
.-~-I A
60 4 g ~40
B
45 g» -60
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30 g -80
15 g -100
0 -120
90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 160 170 1a)
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C) r . '60H7 " 1 035mm D)
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30 k - ‘n‘\ E
\
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15 \f: a h g
0
90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 160 170 180
ka Amie (Degrees!) Crank Amie (Degrees)
E) '" v40H7 ‘ T" 1 100mm F)
75
60 g
B
45 2‘
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30 >0
15 g
0
90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 160 170 1a)
Crank Angle (Degrees) Grad: Angle (Degrees)
G) r . 6QHL A " J '1 00mm H)

 

Figure C9. Effects of Amplitude and Excitation Duration on Peak Vorticity Levels.

 

124

 

 

O—O No Excitation
§ 0 < — l 018011851

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A E] 18 LIL

   

 

 

 

 

 

 

 

 

 

            

 

 

 

 

 

 

 

 

 

         

 

 

 

 

 

 

 

 

    

-0.5 0.1
90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 160 170 lm
Crank Angle( Degrees) CrankAnglemqrees)
A) Frpqupnry' 40 Hz ‘ . P 1 035m B)
1.6 0.7
{ ...... No Excitation K o—o No Emma”
\ at: stages:
1.2 \\ B——E] 015 degg
N n 0— —0 o-so dog
[— ‘ C
a:
g 0.8 E
2
0.4 -
I l/
V
0 0.1
90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 160 170 180
CrankAnglemegrms) kaAxu‘lMDegrees)
C) r . 60Hz ‘ ... 1 035mm D)
2.0 0.7
. . HNol-Ixcimfion
1,5 \ a — A a 013 arises E1360
; \ o— —o 060 deg
g 1 o “k
2 ‘\
0,5 \ “8:\ i
0 v 0 l
90 100 110 120 130 140 150 160 170 180 . 90 100 110 120 130 140 150 160 170 180
kaAngle(Degrees) CrankAmlemrgrms)
E) W F)
2.0 0.6 K
'O—O_ _ I gowfitfiilafinn 0 5 \ I- —- — l fi'igiiieifm
V— - v 40-180 as
1.5 B--E30-18 deg
0-60 deg

 

 

 

 

 

 

0.5 G
-35.“; -
0 .
90 100 110 120 130 140 150 160 170 180 90 100 110 120 130 140 150 160 170 180
Crank Angle (Degrees) Crank Argle (Degrees)
G) W H)

Figure C10. Effects of Amplitude and Excitation Duration on Tumble Ratio.

LIST OF REFERENCES

125

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E
if
1:

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l"

 

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