Search results
Pages
-
-
Title
-
A STUDY ON FLUID-STRUCTURE INTERACTION OF SWIMMING BEAM USING IMMERSED BOUNDARY- LATTICE BOLTZMANN METHOD
-
Creator
-
Rahman, Md Towhidur
-
Date
-
2021
-
Collection
-
Electronic Theses & Dissertations
-
Description
-
Fluid-structure interaction (FSI) study is of great importance to understand the hydrodynamic coupling of biological swimmers in surrounding environmental domain. Multiple numerical and experimental studies have taken place to capture the behavioral pattern from the environment, explore the physical phenomena and comprehension of dynamics to make contribution in real life applications. In this study, an immersed boundary-lattice Boltzmann method (IB-LBM) for fluid-structure interaction...
Show moreFluid-structure interaction (FSI) study is of great importance to understand the hydrodynamic coupling of biological swimmers in surrounding environmental domain. Multiple numerical and experimental studies have taken place to capture the behavioral pattern from the environment, explore the physical phenomena and comprehension of dynamics to make contribution in real life applications. In this study, an immersed boundary-lattice Boltzmann method (IB-LBM) for fluid-structure interaction problems is presented. The impact of solid structure on to the surrounding fluid domain is dealt with by immersed boundary method (IBM), where the structure is assumed to be immersed into surrounding fluid and the effect of the immersed boundary are considered by exertion of Lagrangian force onto the surrounding fluid grid points as body force. The flow dynamics is determined by solving discrete lattice Boltzmann equation of a single relaxation time model. The structural dynamics are solved by the finite difference method. For solving the structural dynamics, inextensibility condition was applied. A staggered grid is used in the Lagrangian coordinate system, where tension force is defined on the interfaces (half-grids) and other variables are defined on the nodes. Tension force is calculated at the intermediate steps and used as inextensibility constraint to obtain filament position at the next time step. In the present study, a detailed derivation and corresponding discretization is done for multiple free-swimming cases for a thin flexible filament. The thin flexible filament is actuated by imposing oscillatory heaving and pitching motion at the leading edge with prescribed control parameters. The flow physics of the system is investigated and pressure on the surfaces of the flexible filament is obtained. The results obtained in this study shows consistency with previous publications. The presented computational modelling may be used in future with multiple obstacles in the domain, to investigate the surface pressure variation of the swimming flexible filament and generated data sets may contribute to optimization of control mechanism of the swimmer.
Show less
-
-
Title
-
A SURFACE WATER δ18O BASELINE FOR ARCHAEOLOGICAL STUDIES OF SEASONALITY AND MOBILITY IN THE MAJES VALLEY AND PUCUNCHO BASIN OF SOUTHERN PERU
-
Creator
-
Milton, Emily Beatrice Peterson
-
Date
-
2020
-
Collection
-
Electronic Theses & Dissertations
-
Description
-
Oxygen isotopes in archaeological human and animal teeth provide a potential means to study past migration. In this thesis I evaluate oxygen isotopes as a way to measure highland site occupation seasonality and human movement between elevation zones in the Central Andes. I focus on two questions: 1) Do surface water δ18O values vary predictably with altitude? and 2) Do surface water δ18O values reliably record the wet and dry season? Using water samples collected from the Majes Valley and...
Show moreOxygen isotopes in archaeological human and animal teeth provide a potential means to study past migration. In this thesis I evaluate oxygen isotopes as a way to measure highland site occupation seasonality and human movement between elevation zones in the Central Andes. I focus on two questions: 1) Do surface water δ18O values vary predictably with altitude? and 2) Do surface water δ18O values reliably record the wet and dry season? Using water samples collected from the Majes Valley and Pucuncho Basin of southern Peru, I establish the seasonal and spatial distribution of δ18O. The final dataset represents 98 water samples collected during wet and dry seasons between 2018-2019, from elevations 36 to 4938 meters above sea level. Surface water δ18O and δD values in the study area are consistent with regional and global meteoric waters. Individual water bodies demonstrate relatively higher δ18O values during the dry season and lower δ18O values in the wet season, matching predictions. Lowland and highland surface waters demonstrate overlapping ranges of δ18O, making it impossible to predict the values of surface waters based on elevation alone. Rather, local δ18O appears to reflect evaporative processes influenced by stream order, catchment size, and the geographic position of a waterbody within the watershed. These data suggest oxygen isotopes are not independently suited to resolve questions of human mobility between elevation zones in the western Andes. Further testing is needed to understand the local seasonal and inter-zonal isotopic ecology.
Show less
-
-
Title
-
A baseline analysis of poaching in Chiquibul National Park
-
Creator
-
Groff, Katherine
-
Date
-
2011
-
Collection
-
Electronic Theses & Dissertations
-
Description
-
Illegal hunting of wildlife, also known as poaching, in Chiquibul National Park (CNP) may be contributing to decreasing wildlife populations. Management strategies are limited due to a lack of information on the extent of poaching and motivations of poachers. The objectives of this research are to assess the extent of poaching, to address Guatemalan border community residents' understanding of wildlife in CNP and what animal species are targeted by hunters, and to investigate factors...
Show moreIllegal hunting of wildlife, also known as poaching, in Chiquibul National Park (CNP) may be contributing to decreasing wildlife populations. Management strategies are limited due to a lack of information on the extent of poaching and motivations of poachers. The objectives of this research are to assess the extent of poaching, to address Guatemalan border community residents' understanding of wildlife in CNP and what animal species are targeted by hunters, and to investigate factors affecting poaching in CNP and Guatemalan border residents' perceptions about poaching in CNP. These objectives were addressed by (1) synthesizing information found in CNP Ranger field notebooks and reports, (2) interviewing Guatemalan border community residents, and (3) interviewing authorities in Guatemala and Belize. Guatemalan border community residents perceived a lower level of poaching in the CNP than CNP rangers, but both thought that poaching has decreased over the years. CNP rangers considered poaching to be a danger to wildlife in the area, and they thought that wildlife numbers have suffered due to poaching. This research demonstrated little support for the hypothesis that legal regulations and the enforcement of regulations are factors that contribute to whether respondents view other community members as contributing to poaching. However, the subsistence needs of hunters and their families is an important factor affecting residents' decision to poach. When subsistence was included in a logistic multivariate regression with legal regulations, regulations lost significance and subsistence was highly significant. Subsistence needs appear to be worth the risk of being caught poaching by authorities.
Show less
Pages
