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1
Ning, Hui. "Thermal diffusion behavior of complex fluid mixture." Enschede : University of Twente [Host], 2008. http://doc.utwente.nl/58719.
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Bjorland, Clayton M. "On the long time behavior of fluid equations /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2008. http://uclibs.org/PID/11984.
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Hwang, Bohyun. "Fluid Behavior in Nano to Micro Confinement Systems." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1593454113844453.
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Albrecht, Karen A. "Observation scale effects on fluid transport behavior of soil." Thesis, Virginia Tech, 1985. http://hdl.handle.net/10919/43037.
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Variabilities of hydraulic and solute transport properties of soil are examined at three scales: pore-scale, sample volume-scale, and field-scale. Undisturbed soil cores were taken at 19 subsites spaced logarithmically along a 150 m line transect in a Groseclose mapping unit near Blacksburg; Virginia. Three core sizes were taken at each subsite at the soil surface and 0.5 m depth. 'Small' cores were-40x54 mm; 'medium' cores were 60X100 mm; and 'large' cores were 100x150 mm. Macropore effects on solute transport
were evaluated using monocontinuum and bicontinuum models. Bicontinuum-predicted solute breakthrough curves
(BTC) closely agreed with observed BTC data with mean errors of reduced concentrations
Master of Science
5
Dvoyashkin, Muslim, Alexey Khokhlov, Rustem Valiullin, Jörg Kärger, and Matthias Thommes. "Fluid behavior in porous silicon channels with complex pore structure." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-190953.
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Dvoyashkin, Muslim, Alexey Khokhlov, Rustem Valiullin, Jörg Kärger, and Matthias Thommes. "Fluid behavior in porous silicon channels with complex pore structure." Diffusion fundamentals 11 (2009) 80, S. 1-2, 2009. https://ul.qucosa.de/id/qucosa%3A14045.
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Humayun, Raashina. "Adsorption-desorption behavior in heterogeneous processes involving supercritical fluid solvents /." The Ohio State University, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488195633518012.
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Thornhill, Lindsey Dorough. "Fatigue behavior of flexhoses and bellows due to flow-induced vibrations." Thesis, Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/17624.
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Yurko, James Andrew 1975. "Fluid flow behavior of semi-solid aluminum at high shear rates." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8451.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2001."June 2001."
Includes bibliographical references (leaves 119-127).
The rheological behavior and microstructure of semi-solid aluminum alloys were studied using a novel apparatus, the Drop Forge Viscometer (DFV). The viscometer determines force from the curvature of displacement data allowing calculations of viscosities at shear rates in excess of 1000 s-1. Alternatively, the DFV can be operated like a conventional parallel-plate compression viscometer, attaining shear rates as low as 10-5 s-1. Durations of an experiment range between approximately 5 ms and 24 hours. Most rapid compression tests resulted in periods of first rapidly increasing shear rate followed by rapidly decreasing shear rate. Viscosity during the increasing shear rate period decreased by 1-2 orders of magnitude. The viscosity during the decreasing shear rate was an order of magnitude smaller (relative to another experiment) when it achieved a 75% greater maximum shear rate. The DFV was used to calculate viscosity as a function of shear rate for Al-Si and Al-Cu alloys that were rheocast with the commercial SIMA and MHD processes, as well as the recently developed MIT method. Experiments were conducted between fractions solid of 0.44 and 0.67. Viscosity of A357 produced by the three processing routes all had similar viscosities, ranging from 300 Pas at 120 s-1 to 2.2 Pas at 1500 s-1. The final height of compressed Al-Cu was always greater than Al-Si for a given set of experimental conditions. Segregation was not observed in rapid compression experiments shorter than 10 ms, either visually or with EDS characterization. At low compression velocities, segregation was observed and increased with the amount of strain.
by James Andrew Yurko.
Ph.D.
10
Bettin, Giorgia. "High-rate deformation behavior and applications of fluid filled reticulated foams." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/42285.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references (p. 169-174).
The need for smarter and adaptive, energy absorption materials especially for human protection applications has fueled the interest in new and alternative energy absorbing composites. In this thesis a 'novel' energy absorbing fluid-composite that utilized a shear thickening fluid is developed. Shear-thickening fluids are a class of field responsive fluids that have the ability to transition from a low viscosity state to a high viscosity state under an imposed deformation field. A shear thickening fluid composed of silica monodisperse spherical particles of 0.3 ± 0.03 /anm diameter dispersed in ethylene glycol at volume fractions up to = 60% has been characterized. The behavior of the silica suspensions is studied under steady shear, small and large amplitude oscillatory shear flow and also in transient extensional flow. Oscillatory experiments indicate that both the onset and magnitude of the shear thickening depends on the frequency and strain applied and show that rapid time-varying deformations result in maximum energy dissipation. Two different regimes are observed in extensional flow measurement: at low extension rates the suspensions respond as a viscous rate-thinning fluid, whereas beyond a critical extension rate, the suspension strain-hardens and ultimately fractures in a solid-like fashion. Polyurethane open cell or 'reticulated' foam with a relative density of 0.03 and average cell size of 360 rpm is chosen to envelop the concentrated silica suspensions. The behavior of this nonlinear fluid-solid composite is studied over a range of filling fractions under quasi-static deformation rates (strain rates between 10-2 - 1 s-1), under dynamic impact loading (with energy densities of e = 105 - 106 J/m3) and under high strain-rate deformations (strain rates up to 800 s-').
(cont.) Results show that, if the foam is filled with a shear thickening suspension, the composite stiffens even at strain rates of 10-2 s-1 as the impregnated fluid shear-thickens due to the high local strain rates that develop on cellular length scales. Experiments at high impact loadings revealed two different mechanisms for energy absorption: at low impact energies viscous dissipation is dominant; whereas after a critical impact energy is reached, the fluid undergoes a transition from liquid-like to solid-like. High-speed digital video-imaging shows that cracks form and propagate through the sample and the impact energy is absorbed by viscoplastic deformation. Potential applications for this fluid-solid composite include Traumatic Brain Injuries (TBI) protection and Primary Blast Injuries (PBI) mitigation. Traumatic Brain Injury (TBI) is a serious and potentially fatal injury that results from rapid accelerations of the head, and subjects the brain to high intracranial pressure and shear stresses. To reduce TBI damage, one needs to reduce the magnitude and rate of increase of the intracranial overpressure created by blasts or impacts and subsequent accelerations of the head. We investigated the use of the shear-thickening fluid-based composite to mitigate TBI and we found that through the mechanism of viscoplastic deformation, with solidification and shear banding, the composite was able to absorb large amount of energies (106 J/m3) and still maintain stresses below critical levels. Additionally, the energy absorbing properties of the composite were found to be independent of the magnitude of the incoming energy. Blast injuries are caused by high rate loading of the chest cavity after impact from a blast wave.
(cont.) The resultant pressure wave is transmitted and reflected inside the chest cavity where, at certain points, the pressure gradient became too big for the alveoli to sustain resulting in bursting and bleeding. A shock tube apparatus has been used to test the material response of the STF based composite. Single layer geometries have shown to provide some protection but they also always induced a magnification of the peak pressure which is related to the weight of the samples. A sandwich geometry formed by layering fluid-filled foam facing the incoming wave backed by unfilled foam is found to reduce the rate of pressure rise by 3 orders of magnitude. This behavior can be well described by a double spring-mass-damper system. The layered composite is found to respond linearly with increases in incoming pressure, as the rate of pressure rise has a linear relationship with the magnitude of the incoming pressure. The results found in this study suggest that the STF based composite is an excellent candidate for use in applications of both TBI protection and PBI mitigation.
by Giorgia Bettin.
Ph.D.
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Lee, Wing-yan, and 李永仁. "Global behavior of a round buoyant jet in a counterflow." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B35312531.
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Ramesh, Vishal. "Modeling Freeze/Thaw Behavior in Tanks for Selective Catalytic Reduction (SCR) Applications." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu156328011301541.
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Percy, Cayman Michele. "The influence of fluid mechanics on the orientation behavior of blue crabs." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/19516.
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Napari, Ismo. "Density functional theory of nucleation and phase behavior in binary fluid systems." Helsinki : University of Helsinki, 2000. http://ethesis.helsinki.fi/julkaisut/mat/fysii/vk/napari/.
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Thompson, Willis Hope III. "Numerical Analysis of Thermal Behavior and Fluid Flow in Geothermal Energy Piles." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/24013.
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Geothermal heat exchangers are a growing energy technology that improve the energy efficiency of heating and cooling systems in buildings. Vertical borehole heat exchangers (BHE) coupled with ground source heat pumps have been widely developed and researched in the past century. The major disadvantage of BHEs is the initial capital cost required to drill the boreholes. Geothermal energy piles (GEP) were developed to help offset the high initial cost of these systems. A GEP combines ground source heat pump technology with deep earth structural foundations of buildings. GEPs are relatively new technology and robust standards and guidelines have not yet been developed for the design of these systems. The main operational difference between GEPs and conventional BHEs is the length and diameter of the below ground heat exchangers. The diameter of a GEP is much larger and the length is typically shorter than BHEs. Computational fluid dynamics (CFD) analysis is used in this study to investigate and better understand how structural piles perform as geothermal heat exchangers.
The CFD analysis is used to simulate an existing experimental energy pile test. The experimental test is modeled as built including fluid modeling to provide additional detail into the behavior of the circulation fluid within the pile. Two comparisons of large diameter GEPs are made using CFD analysis to gain knowledge of the effects of varying pile diameter and loop configuration. The thermal response test was successfully modeled using the CFD model. The CFD results closely match the results of the field test. The large diameter comparisons show that the performance of an energy pile will increase as the diameter increases with a constant loop density. Multiple numbers of loops were tested in a constant diameter pile and the results show that with symmetrically placed loops the performance will increase with a greater number of loops in the pile.Master of Science
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Burns, Katherine Eileen. "Influence of Fluid Dynamics on Silver Nanoparticle Behavior and Monocytic Cellular Response." University of Dayton / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1532533724899619.
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Wu, Yue. "Experimental Determination and Equation of State Modeling of High-Pressure Fluid Behavior." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/3237.
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High-pressure solution behavior such as density and phase behavior is a critical fundamental property for the design and optimization of various chemical processes, such as distillation and extraction in the production and purification of oils, polymers, and other natural materials. In this PhD study, solution behavior data are experimentally determined and equation of state (EoS) modeled for n-hexadecane, n-octadecane, n-eicosane, methylcyclohexane, ethylcyclohexane, cis-1,2-dimethylcyclohexane, cis-1,4-dimethylcyclohexane, trans-1,4-dimethylcyclohexane, o-xylene, m-xylene, p-xylene, and 2-methylnaphthalene at temperatures to 525 K and pressures to 275 MPa. A variable-volume view cell coupled with a linear variable differential transformer is used for the high-pressure determination. The reported density data are less than 0.4% of available literature data, which is within the estimated accumulated experimental uncertainty, 0.75%. Special attention is paid to the effect of architectural differences on the resultant high-pressure solution behavior. The reported data of low molecular weight hydrocarbons are modeled with Peng-Robinson (PR) equation of state (EoS), high-temperature high-pressure volume-translated cubic (HTHP VT-cubic) EoS, and perturbed-chain statistical fluid theory (PC-SAFT) EoS. The three pure-component parameters in PC-SAFT EoS can be either obtained from literature or from a group contribution (GC) method. Generally, PR EoS gives the worst predictions and HTHP VT-cubic EoS provides modest improvements over the PR EoS, but both of the equations underpredict the densities at high pressures. On the other hand, PC-SAFT EoS, with parameters from the literature or from a GC method, gives the improved density predictions with respect to PR EoS and HTHP VT-cubic EoS, although an overprediction of densities is found at high pressures. Model calculations also highlight the capability of these equations to account for the different densities observed for the hydrocarbon isomers. However, none of the EoS investigated in this study can fully account for the effect of isomeric structural differences on the high-pressure densities. For a better prediction of densities at high pressures, a new set of PC-SAFT pure-component parameters are obtained from a fit of the experimental density data obtained in this study and the mean absolution percent deviation is within 0.4%. The experimental technique and PC-SAFT EoS modeling method are extended to a star polymer-propane mixture. Star polymers with a fixed number of arms have a globular structure that does not promote chain entanglements. Star polymers can be synthesized with a large number of functional groups that can be readily modified to adjust their physical properties for specific applications in the areas of catalysis, coatings, lubrication, and drug delivery. In this study, a star polymer with a divinylbenzene core and statistically random methacrylate copolymer arms is synthesized with reversible addition-fragmentation-transfer method and fractionated with supercritical carbon dioxide and propane to obtain fractions with low molecular weight polydispersity. The phase behavior and density behavior are experimentally determined in supercritical propane for fractionated star polymers and the corresponding linear copolymer arms at temperatures to 423 K and pressures to 210 MPa. Experimental data are presented on the impact of the molecular weight, the backbone composition of the lauryl and methylmethacrylate repeat units in the copolymer arms, and the DVB core on the polymer-propane solution behavior. The star polymer is significantly more soluble due to its unique structure compared with the solubility of the linear copolymer arms in propane. The resultant phase behavior for the two homopolymers and the copolymers in propane are modeled using the PC-SAFT and copolymer PC-SAFT EoS, which give reasonable predictions for both phase behavior and density behavior. Model calculations are not presented for the phase behavior of the star polymers in propane since the PC-SAFT approach is not applicable for star polymer structures.
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Yaku, Koji. "STUDIES ON CHARACTERIZATION OF RETENTION AND SEPARATION BEHAVIOR IN SUPERCRITICAL FLUID CHROMATOGRAPHY." Kyoto University, 2000. http://hdl.handle.net/2433/181011.
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Cheong, Poh Leng. "Phase behavior of the naphthalene-carbon dioxide system at supercritical fluid conditions." Thesis, University of Ottawa (Canada), 1985. http://hdl.handle.net/10393/4805.
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Love, Peter John. "Three dimensional lattice gas models for amphiphilic fluids." Thesis, University of Oxford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365431.
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Park, Chang Shin. "A dynamic behavior of pulp floc and fibers in the papermaking process." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/7044.
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Howes, Karsten. "Lattice gases in statistical physics : a study of phase separation, critical behavior and other phenomena." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=68184.
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The studies which are presented here are computer simulations of fluid phenomena based on 2D lattice gas models of the kind first described by Frisch et al. (1986). The primary advantage of using these models is that they are easily implemented on massively parallel computers and as a result are extremely fast.The first of these studies is of a model of phase separation in binary fluids. The growth laws of the fluid domains are examined and are shown to compare favourably to theoretical predictions of San Miguel et al. (1985). This appears to be a first verification of these results. The second study is of the critical behavior of a system of binary fluids. The model is shown to have a phase transition and the critical temperature is determined with an accuracy of 1%. Several critical exponents are also determined and evidence is provided that the model falls into the 2D Ising model universality class. A new model of fluid convection is also presented though no concrete results are yet available for this model.
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Chisum, James E. "Simulation of the dynamic behavior of explosion gas bubbles in a compressible fluid medium." Diss., Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1996. http://handle.dtic.mil/100.2/ADA326363.
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Dissertation (Ph.D. in Mechanical Engineering) Naval Postgraduate School, December 1996.Dissertation supervisor(s): Young S. Shin. "December 1996." Includes bibliographical references (p. 81-83). Also available online.
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Kwon, Ronald Young. "Mechanical behavior and early molecular signaling during mechanotransduction of fluid flow in bone cells /." May be available electronically:, 2008. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Horan, Aiden James. "The mechanical behavior of normally consolidated soils as a function of pore fluid salinity." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/73793.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 339-344).
Pore fluid salinities in the Gulf of Mexico area can reach levels of 250 grams of salt per liter of pore fluid (g/1). It is now necessary to determine the effect that this salinity level can play on the mechanical behaviors of marine sediments. An extensive laboratory testing program involving Constant Rate of Strain (CRS) and Ko consolidated undrained shear in compression triaxial testing (CKoUC) was undertaken. Soil specimens reached axial effective stresses of 10 MPa with a select few reaching 40 MPa in a modified CRS device. All triaxial tests were performed in a low pressure triaxial apparatus. The shear behavior of all soils was obtained in the normally consolidated region. Several reverse leaching tests were performed in the CRS cell whereby high salinity pore water was flushed through a low salinity soil while consolidation was halted. The majority of testing was performed on resedimented specimens using several different soils from around the world. These include Boston Blue Clay (BBC), London Clay, Gulf of Mexico soil and sodium montmorillonite. Several derivatives of BBC were resedimented including BBC which had some of its natural salt removed via leaching, and also BBC which had its fabric completely dispersed using sodium hexametaphosphate. Pore fluid salinities ranging from 0 (distilled water) to 256 g/l were used when resedimenting these soils. The resedimented BBC test results were compared to intact BBC soil which was recovered from below the MIT campus. The results show that BBC and London Clay are relatively insensitive to increases in pore fluid salinities up to 256 g/l. This sensitivity can be increased by leaching some of the natural salt from the soil and then resedimenting to different pore fluid salinities. The strength characteristics of BBC over this large salinity range also remain fairly constant with the only differences being observed in leached BBC. It was also seen that the strain to failure for resedimented BBC is half that which is required for intact soil with all other measured parameters being similar. Interesting observations were seen in relation to how the fabric of BBC evolves with an increase in stress level and a theory of how floc breakage occurs at a given stress level is proposed. A potential crude method of quantifying the contribution of electro-chemical forces to a soils strength is also suggested
by Aiden James Horan.
S.M.
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Waisbord, Nicolas. "Magnetotactic bacteria as a driven active fluid : from single swimmer behavior to collective effects." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10223.
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We report the work we lead on magneto tactic bacteria, from the point of view of active matter. The ability of this bacterium to swim at 100µm/s directed by the magnetic field makes it a good candidate to study driven active matter. Indeed, in this configuration, the self-propelled system is not dragged by an external force, and its directed motion comes from its biased orientation. We choose the strain MC-1 for our study, for the robustness of its individual behavior and its swimming speed. We studied the individual behavior, confirming previous results where the bacteria passively aligns on the magnetic field being disoriented solely by the magnetic field, but also succeeded in triggering activity in their reorientation, suspending it in different chemical environments, or directing them against a solid interface, where this bacteria could tumble. This tumbling behavior, very common amongst non-magnetic bacteria, was not reported for Mangetotactic bacteria. These new results leaded us to develop a model of Run and Tumble under a magnetic field. We studied their behavior when densely concentrated in a micro-channel, in jammed configuration, using standard microfluidics tools. We observed their motion in hour glass shaped micro-channels, without any flow, and characterized the chronology of the jamming process. We investigated the interaction of their swim with a shear, in a counter flow experiments, where MC-1 would be directed against a Poiseuille flow. Due to equilibrium between the magnetic torque and the hydrodynamic shear, bacteria would focus instantly in the middle of the channel. We studied this phenomenon theoretically, and checked our model with the experiments. We discovered a instability of a new kind in the same configuration, for high magnetic fields. Indeed, beyond a threshold the focused suspension would become wavy to end up in segregated droplets of bacteria. We characterized experimentally this phenomenon which reminds us of Rayleigh-Plateau and Kelvin-Helmholtz instabilities, varying the flow rate, the Magnetic field and the density of the suspension. Recirculation in the droplets is observed and explained. We interpret these convection droplets as the source of the instability of the focused suspension
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Tabiatnejad, Bardia. "Impact of pore fluid chemistry on mechanical and thermal behavior of clay-based materials." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/60297.
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The impact of pore fluid salinity on thermal and mechanical properties of clay-based materials are examined in this thesis. The proposed concept for deep geological repository in Canada consists of a series of clay-based material to support the used-fuel bundles in place and minimize the local groundwater infiltration, which is highly saline. The coupled process of local groundwater infiltration and thermal desiccation in the engineered barrier causes the material to experience unsaturated conditions with increased salt content levels. In the previous studies, the behavior of the material has been investigated in the distilled water conditions, which was necessary to consider the change in the pore fluid salinity considering the infiltration of the groundwater. This research investigates the impact of the pore fluid salinity on the mechanical behavior and thermal conductivity of the clay-based materials which are designed to be use in the repository in future. To accomplish this, three experimental testing programs have been carried out. The first experimental program examined the shrinkage and stress-strain behavior of bentonite-sand buffer specimens prepared with high and low salt concentrations. The results were compared to the available data from the literature for the specimens prepared with distilled water. Specimens were dried out in desiccators and installed in triaxial cells. The soil water characteristic, compression and shear strength of the specimens were presented and impact of the pore fluid salinity was discussed. The second experimental program evaluated the effect salinity of the pore fluid on the behavior of the light backfill material in unsaturated conditions. Specimens prepared with distilled water and saline solution were tested and their compressibility and shear strength were discussed. The third experimental program investigated the impact of pore fluid salinity on the thermal conductivity of mixtures of bentonite and silica sand at low and high dry densities. In continue, a number of thermal conductivity prediction models were selected to calculate the thermal conductivity values of the material with distilled water and saline pore fluids. The calculated values were compared to the obtained experimental data and a suitable model for predicting thermal conductivity in the saline pore fluid condition was presented.Applied Science, Faculty of
Engineering, School of (Okanagan)
Graduate
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Redmon, Jessica. "Stochastic Bubble Formation and Behavior in Non-Newtonian Fluids." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case15602738261697.
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Tang, Yiping. "A study of fluid behavior by a general analytical solution of the Ornstein-Zernike equation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq26141.pdf.
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Montazer, Mohammad. "Effect of geometry on the behavior of steady Newtonian fluid in a multiply connected domain." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46222.
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We start with the prototype problem of flow of a Newtonian fluid in the annular region between two infinitely long circular cylinders, with the given
velocity and temperature on the boundaries of the domain.
Then we will try to find out how does geometry affect the behavior of the flow inside of the domain. We will explore two invariant mappings
K_T and K_psi , such that under appropriate conditions on the boundary, the mapping K_T would preserve solution of temperature field from one domain to another and the mapping k_psi would preserve solution of velocity field.
We will prove that if a mapping is conformal, it would preserve the convection-diffusion equation in both domains. After that, we will find which subsets of the conformals would also preserve the velocity field as well. In order to answer that question, we will obtain the required condition for the mapping , such that it would preserve both velocity and temperature fields, from one domain to another.
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Fu, An. "Investigation of Fluid Wicking Behavior in Micro-Channels and Porous Media by Direct Numerical Simulation." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1563272437544414.
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Azbej, Tristan. "The Role of Fluids in Geological Processes." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/29074.
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The role and behavior of fluids in hydrothermal and magmatic environments have been studied. Experimental studies have been carried out to determine fluid properties, in natural environments and in both synthetic and natural fluid and melt inclusions.
One of these studies dealt with the effect of composition on the critical P-T-X properties of aqueous salt solutions approximated by the H2O-NaCl-KCl-CaCl2 system. The results indicate a systematic variation in critical properties as a function of composition over the range of P-T-X studied.
A technique for analyzing individual H2O-CO2 inclusions using Raman spectroscopy has also been developed. The resulting empirical equation relating Raman intensities and composition is valid for compositions â ¤50mol% CO2. The technique has been applied to H2O-CO2 inclusions from the Butte, MT Porphyry Cu-Mo deposit and the results agree with compositions estimated from microthermometric and petrographic observations.
The aim of another study was to study water loss from melt inclusions during laboratory heating. Melt inclusions had lost insignificant amounts of water when held at experimental conditions (800°C, 1 kbar) for ⠤24 hours. However, significant water loss was observed for longer duration experiments.
Ocelli, which are globular bodies of felsic minerals are interpreted as products of magmatic melt immiscibility. As such, the carbonate aggregates in Cretaceous lamprophyres from Hungary with similar petrographic characteristics have also generally been interpreted to be products of magmatic immiscibility. Petrographic and geochemic studies have shown three three distinct genetic groups for these aggregates, none of which were consistent with a magmatic origin.Ph. D.
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Alarcón, Oseguera Francisco. "Computational study of the emergent behavior of micro-swimmer suspensions." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/394065.
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It is known that active particles induce emerging patterns as a result of their dynamic interactions, giving rise to amazing collective motions, such as swarming or clustering. Here we present a systematic numerical study of self-propelling particles; our main goal is to characterize the collective behavior of suspensions of active particles as a result of the competition among their propulsion
activity and the intensity of an attractive pair potential. Active particles are modeled using the squirmer model. Due to its hydrodynamic nature, we are able to classify the squirmer swimmer activity in terms of the stress it generates (referred to as pullers or pushers). We show that these active stresses play a central role in the emergence of collective motion. We have found that hydrodynamics drive the coherent swimming between swimmers while the swimmer direct interactions, modeled by a Lennard-Jones potential, contributes to the swimmers' cohesion. This competition gives rise to two different regimes where giant density fluctuations (GDF) emerge. These two regimes are differentiated by the suspension alignment; one regime has GDF in aligned suspensions whereas the other regime has GDF of suspensions with an isotropic orientated state. All the simulated squirmer suspensions shown in this study were characterized by a thorough analysis of global properties of the squirmer suspensions as well as a complementary cluster analysis.
Active matter refers generically to systems composed of self-driven units, active particles, each capable of converting stored or ambient free energy into systematic movement. Examples of active systems are found at all length scales and could be classified in living and nonliving systems such as microorganisms, tissues and organisms, animal groups, self- propelled colloids and artificial nanoswimmers. Specifically, at the micro and nano scale we find an enormous range of interesting systems both biological and artificial; e.g. spermatozoa that fuse with the ovum during fertilization, the bacteria that inhabit our guts, the protozoa in our ponds, the algae in the ocean; these are but a few examples of a wide biological spectrum. In the artificial world we have self- healing colloidal crystals and membranes as well as self- assembled microswimmers and robots. Experiments in this field are now developing at a very rapid pace and new theoretical ideas are needed to bring unity to the field and identify "universal" behavior in these internally driven systems.
One important feature of active matter is that their elements can develop emergent, coordinated behavior; collective motion constitutes one of the most common and spectacular example. Collective motion is ubiquitous and at every scale, from herds of large mammals to amoeba and bacteria colonies, down to the cooperative behavior of molecular motors in the cell. The behavior of large fish schools and the dance of starling flocks at dusk are among the most spectacular examples. From a physical perspective collective motion emerges from a spontaneous symmetry breaking that allows for long-range orientational orden The different mechanisms responsible for such symmetry breaking are still not completely understood. We have performed a systematic numerical study of interactive micro-swimmer suspensions building on the squirmer model, introduced by Lighthill. Since the squirmer identifies systematically the hydrodynamic origin of self-propulsion and stress generation it provides a natural scheme to scrutinize the impact that the different features associated to self-propulsion in a liquid medium have in the collective dynamics of squirmer suspensions. In this abstract we describe the simulation scheme and how squirmers are modeled, then some of the main results are discussed and finally we conclude emphasizing the main implications of the results obtained.Los sistemas activos se definen como materiales fuera del equilibrio termodinámico compuestos por muchas unidades interactuantes que individualmente consumen energía y colectivamente generan movimiento o estreses mecánicos. Ejemplos se pueden encontrar en un enorme rango de escalas de longitud, desde el mundo biológico hasta artificial, incluyendo organismos unicelulares, tejidos y organismos pluricelulares, grupos de animales, coloides auto-propulsados y nano-nadadores artificiales. Actualmente se están desarrollando experimentos en este campo a un ritmo muy veloz, en consecuencia son necesarias nuevas ideas teóricas para traer unidad al campo de estudio e identificar comportamientos “universales” en estos sistemas propulsados internamente. El objetivo de esta tesis es el estudiar mediante simulaciones numéricas, el comportamiento colectivo de un modelo de micro-nadadores. En particular, el modelo de squirmers, donde el movimiento del fluido es axi-simétrico. Existen estructuras coherentes que emergen de estos sistemas así que, el entender si las estructuras coherentes son generadas por la firma hidrodinámica intrínseca de los squirmers individuales o por un efecto de tamaño finito se vuelve algo de primordial importancia. Nosotros también estudiamos la influencia que tiene la geometría en la aparición de estructuras coherentes, la interacción directa entre las partículas, la concentración, etc.
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Ogbuagu, Too-chukwu C. "Numerical Investigation of the Near FieldZone Flow Behavior of Isothermal CornerImpinging Jet Ventilation Using CFD." Thesis, Högskolan i Gävle, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-35982.
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Abstract The impinging jet ventilation's importance in providing better air distribution and energy-efficient operation, as well as both its heating and cooling flexibility potential cannot be overemphasized. This is because acceptable indoor air quality and its environmental conditions are essential to occupant’s wellbeing, comfort, productivity, and improved cognitive function. Poor air quality conditions could result in sick building symptoms (SBS) and several studies have investigated that the prevalence of sick building symptoms is associated with indoor air quality. Consequently, to the need for high ventilation effectiveness, the impinging jet ventilation system has been developed and applied in different types of buildings as a new ventilation strategy and concept within the last two decades. Therefore, it is important to continuously develop inventive air distribution systems such as IJV with a better location and terminal configuration of the supply device to adequately provide an acceptable indoor environment in an energy-efficient manner. This study aims at reaching a comprehensive understanding of the near field zone of an isothermal turbulent corner impinging jet in a room by using computational fluid dynamics (CFD) simulation tool. Thus, directly investigating the flow field involving the velocity magnitude, velocity decay, and spreading rate along the diagonal of the room.The cases carried out consist of 12 different three-dimensional modeled configurations (room) of the computational domain with the dimension 7.0 (L) x 7.0 (W) x 2.67 (H) m. The cases which comprised different aspects of diffuser geometry (triangle, quadrant, square), diffuser area, discharge height, and flow rates, used the RNG k-ε turbulence model to solve the turbulence flow.The result obtained, from the parametric study in all the cases was detailed to analyze the effect of the different flow rate, discharge heights, diffuser geometry, and its area on the velocity profile development, velocity decay, and spreading rate along the diagonal of the room. This study significantly shows the triangular geometries having greater velocity magnitude and velocity decay along all the line profile positions. Interestingly, a comparison between the quadrant and square geometry illustrates that their characteristics of generating a greater velocity magnitude depend on its discharge height. The result also demonstrated a decrease in jet velocity decay with an increase in jet discharge height. With similar jet spread at higher jet discharge, the square geometry exhibited a higher spreading rate at lower discharge height.
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Mendez-Gallardo, Valerie. "Opioid mediated behavioral effects and learning in the neonatal rat: comparison between amniotic fluid and milk." Diss., University of Iowa, 2011. https://ir.uiowa.edu/etd/1248.
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The purpose of this study was to explore the behavioral effects of amniotic fluid (AF) and milk in the newborn rat. Previous research has documented behavioral effects in the fetal and neonatal rat. For example, oral exposure to AF and milk reduces the response to chemosensory stimulation in rat fetuses (Korthank & Robinson, 1998) and newborns (Méndez-Gallardo & Robinson, 2010). In addition, some of the behavioral effects of AF and milk are mediated by the endogenous opioid system in the perinatal rat, including modulation of the facial wiping response (Korthank & Robinson, 1998; Méndez-Gallardo & Robinson, 2010), the stretch response induced by milk in the fetal rat (Smotherman & Robinson, 1992b), and the effect of milk as an unconditioned stimulus (US) during associative learning in the fetal rat (Robinson et al., 1993). Taking into account the literature that suggests similarities between AF and milk, this study aimed to evaluate whether transnatal continuity in the behavioral effects of AF and milk could be found and whether mediation by the endogenous opioid system is the underlying mechanism of these effects. To fulfill this purpose, overall behavioral activation, crawling locomotion, oral responses to an artificial nipple, and associative learning were investigated in the newborn rat. Results showed that, (a) oral exposure to AF resulted in higher levels of behavioral activation than oral exposure to milk, (b) exposure to the odor of AF or milk did not produce significant behavioral activation, although the odor of milk seemed to evoke higher levels of behavioral activity than exposure to the odor of AF, (c) both AF and milk odor elicited crawling locomotion, (d) odor of AF or milk did not promote oral grasping of an artificial nipple, but promoted mouthing responses and distinctive movements of the forepaws, (e) contingent presentations of an artificial nipple as the conditioned stimulus (CS), with AF or milk as the US, promoted mouthing responses during reexposure to the CS, but facial wiping after CS reexposure was not modified as a result of conditioning, and (f) mediation of the opioid system was evident only during hindlimb activity after oral exposure to AF or milk and during mouthing responses to the CS after associative learning. These findings suggest that oral exposure to AF or milk consistently evoke opioid responses in the neonatal rat, but exposure to the odor of AF or milk alone does not. Through postnatal testing and the direct comparison of the behavioral effects of AF (a feature of the prenatal environment) with milk (a feature of the postnatal environment), this study contributes to a better understanding of mechanisms that promote behavioral continuity before and after birth.
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Hurley, Seth W. "The sensitization of sodium appetite: Plasticity in neural networks governing body fluid homeostasis and motivated behavior." Diss., University of Iowa, 2015. https://ir.uiowa.edu/etd/1635.
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When most omnivores and herbivores become sodium depleted they engage in the motivated behavior of sodium appetite (AKA salt appetite), or the seeking out and ingestion of salty substances. Sodium appetite is associated with psychological processes that serve to enhance the incentive and rewarding value of salty substances in order to attract animals to salty substances and reinforce the ingestion of them. The experience of sodium depletion also produces long-lasting changes in behavior; one of the most apparent changes being a seemingly life-long increase in hypertonic salt intake which indicates sodium appetite is sensitized. Two neural circuits have been implicated in the sensitization of sodium appetite: 1) a forebrain neural circuit that regulates body fluid homeostasis, and 2) the mesolimbic dopamine system which mediates motivated behaviors. This dissertation has three aims that serve the overall purpose of providing a better understanding of the neurobiological mechanisms that mediate the sensitization of sodium appetite. The first aim is to develop a model of sodium depletion that is amenable to pharmacological manipulation in order to determine whether the -blockade of N-methyl-d-aspartate receptors, which are critical for neural plasticity, will prevent the sensitization of sodium appetite. The second aim is to determine whether sensitization is associated with relatively long-term molecular changes in forebrain areas that regulate body fluid homeostasis. The third aim is to identify how forebrain areas involved in body fluid homeostasis may connect to and influence activity in the mesolimbic dopamine system.
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Eberle, Aaron Paul Rust. "The Dynamic Behavior of a Concentrated Composite Fluid Containing Non-Brownian Glass Fibers in Rheometrical Flows." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/28235.
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With this research, we work towards the overall objective of being able to accurately simulate fiber orientation in complex flow geometries of composite fluids of industrial significance. The focus of this work is to understand the rheological behavior of these materials and its connection to fiber orientation as determined in simple shear flow. The work includes the development of a novel approach to characterizing the transient rheology; an experimental study of the relationship between the stress growth functions in startup of flow and the fiber orientation; a critical assessment of the limitations of current fiber suspension theory; and an approach to determining unambiguous model parameters by fitting.
A key difference between the rheological studies performed in this work and others is the use of a cone-and-plate device combined with â donutâ shaped samples (CP-D) to prevent boundary effects on the measurement. The conventional method for obtaining transient rheological data is to use parallel disk (PP) geometry set at a gap where the measurements are independent of disk spacing. However, this work suggests that the inhomogeneous velocity gradient imposed by the PP geometry induces excessive fiber-fiber contact contributing to exaggerated measurements of the stress growth functions.
An experimental study of the transient rheological behavior of a 30 wt% short glass fiber-filled polybutylene terephthalate was performed using the CP-D. Stress growth measurements during startup of flow were performed in combination with direct measurement of the fiber orientation to determine the relationship between the transient rheology and the fiber microstructure. The well defined fiber orientation and rheological experiments allowed for a quantitative assessment of current fiber suspension theory. Comparison between the experimental fiber orientation and predictions based on Jefferyâ s equation and the Folgar-Tucker model show that the fiber orientation evolves much slower than predicted. In addition, the addition of a â slipâ term improved the agreement between the predictions and experimental results. Predictions using the Lipscomb model coupled with the Folgar-Tucker model, with slip, were fit to the transient stresses to determine the feasibility of fitting unambiguous model parameters for a specific composite fluid. Model parameters determined by fitting at a shear rate of 6 s-1 allowed for reasonable predictions of the transient stresses in flow reversal experiments at all the shear rates tested.Ph. D.
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Cao, Da. "Modelling of the vibrational behavior of housing plates filled with fibrous material." Thesis, KTH, MWL Marcus Wallenberg Laboratoriet, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-276478.
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Silencers are used in vehicles to reduce the noise in the engine system. How-ever, silencers themselves may produce break-out noise due to the interaction with the exhaust gas flow and structure. In this Master thesis project, the numerical simulation of vibrational behavior of housing plates of silencers is developed.The housing plate is composed of two steel plates and a fibrous material layer. Measurement results show that the fibrous material has good damping effect to decrease the vibration and radiated sound of steel plates. Steel plates are connected by spot welding. Modeling of spot welds can improve the modal assurance criterion between simulation and measurements. Interface damping is introduced into the simulation models to simulate the contact effect between two steel plates so that the simulated amplitude can have a good agreement with measurement result.Several numerical models of fibrous material are investigated. The Miki model is not chosen for the final result due to the limit of range of frequencies. The rigid frame model can simulate the sound absorption but is unfeasible for the simulation of vibration. The limp frame model can simulate the vibration of light glass wool but cannot simulate the vibration of heavy glass wool. Finally, the Biot-Allard model which is a poro-elastic model is investigated for the final result. The simulation results show good agreement with the measurement result.Ljuddämpare används i fordon för att används för att minska buller i motorsystemet. Ljuddämpare kan emellertid själva producera utbrottsbuller på grund av samspelet mellan avgassflödet och ljuddämpare. I detta examensarbete utvecklas den numeriska simuleringen av vibrationsbeteende hos husplåter för ljuddämpare. Husplåten består av två Plåtar av stål och ett fibröst materiallager. Resultaten av mätningen visar att det fibrösa materialet har god dämpningseffekt för att minska det utstrålade ljudet och vibrationen hos plåterna. Plåterna ansluts med punktsvetsning. Modellering av punktsvetsar kan förbättra kriteriet för modal försäkring mellan simulering och mätning. Dämpning av gränssnitt införs i simuleringsmodellerna för att simulera kontakteffekten mellan två plåtar så att simuleringsamplituden kan ha ett bra överensstämmelse med mätresultatet. Flera numeriska modeller av fibröst material undersöks i detta projekt. Miki-modellen används inte för slutresultatet på grund av gränsen för frekvensområden. Stiv modell kan simulera ljudabsorptionen men är omöjlig för simulering av vibrationer. Limpmodell kan simulera vibrationer av lätt glasull men kan inte simulera vibrationer av tung glasull. Slutligen undersöks Biot-Allard-modellen som är en poroelastisk modell för slutresultatet. Simuleringsresultaten visar bra överensstämmelse med mätresultatet.
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Vu, Si Man. "Effect of heat treatment, oxidation and passivation on corrosion behavior of titanium alloy in simulated body fluid." Thesis, University of Macau, 2010. http://umaclib3.umac.mo/record=b2493961.
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Rodríguez, Alvarado Juan Fernando. "Validation of a numerical model for the analysis of thermal-fluid behavior in a solar concentrator vessel." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/59936.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 44).
The need for innovation in the renewable energy sector is an ever-growing concern. With national-level disasters in the Gulf of Mexico, the necessity to begin the drive to develop effective and practical alternative energy sources becomes a more pressing concern. The CSPond project is an attempt to design a more simple solar thermal energy generation system that additionally addresses the intermittence issue. The CSPond system calls for a large container in which special salt mixtures are molten by solar thermal energy. The large container also acts as a thermal energy storage to address the intermittence issue that has held back the widespread application of solar energy systems. This thesis presents a validation analysis of a numerical simulation of a molten salt system. The simulation is part of a larger design effort to develop a viable solar thermal energy option which incorporates short to medium-term thermal storage. To validate the numerical model, a scaled version of the proposed solar vessel was used in the solar simulator built by Professor Slocum's PERG to simulate normal operation procedures. This data was then compared to the numerical simulations. This comparison found that the numerical simulation does not capture the dynamics of the temperature rise in the system, but that it does capture the Rayleigh-Taylor instabilities, characteristic of convection. Solutions to the issues identified above are proposed and analyzed. These include the consideration of several modes of thermal interactions with the environment, the optical interactions between the solar beam and the molten salt medium, modifying the boundary conditions and finally, including the temperature of all relevant thermophysical properties to better capture the convective behavior of the molten salt system.
by Juan Fernando Rodríguez Alvarado.
S.B.
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Kim, Hayoung. "Analysis of the dynamic behavior of fluid-granular soil-structure systems in waterfront areas of high seismicity." 京都大学 (Kyoto University), 2005. http://hdl.handle.net/2433/138505.
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de, Carvalho Jacobina Andrade Deraldo. "Molecular Dynamics Study of Nano-confinement Effect on Hydrocarbons Fluid Phase Behavior and Composition in Organic Shale." Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/102912.
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The depletion of conventional oil reservoirs forced companies and consequently researchers to pursue alternatives such as resources that in the past were considered not economically viable, in consequence of the high depth, low porosity and permeability of the play zone. The exploration challenges were overcome mainly by the development of horizontal drilling and hydraulic fracturing. However, the extremely high temperatures and pressures, in association to a complex nanopore structure, in which reservoir fluids are now encountered, instigate further investigation of fluid phase behavior and composition, and challenge conventional macroscale reservoir simulation predictions. Moreover, the unusual high temperatures and pressures have increased the cost as well as the hazardous level for reservoir analyzes by lab experiments. Molecular Dynamics (MD) simulation of reservoirs can be a safe and inexpensive alternative tool to replicate reservoir pore and fluid conditions, as well as to monitor fluid behavior.
In this study, a MD simulation of nanoconfinement effect on hydrocarbon fluid phase and compositional behavior in organic shale rocks is presented. Chapter 1 reviews and discusses previous works on MD simulations of geological resources. With the knowledge acquired, a fully atomistic squared graphite pore is proposed and applied to study hydrocarbon fluid phase and compositional behavior in organic shale rocks in Chapter 2. Results demonstrate that nano-confinement increases fluid mass density, which can contribute to phase transition, and heptane composition inside studied pores. The higher fluid density results in an alteration of oil in place (OIP) prediction by reservoir simulations, when nano-confinement effect is not considered.Master of Science
Petroleum sub products are present in the day to day life of almost any human. The list include gasoline, plastics, perfumes, medications, polyester for clothing. Petroleum is naturally encountered in the void space, known as pores, inside rocks at reservoirs thousands of feet underground. In the past, the pores of oil reservoirs in development were larger and interconnected, which facilitates its extraction and reserve predictions. Most of reservoirs being developed nowadays have pores in the nanoscale and with poor interconnection as well as higher reservoir temperatures and pressure. These "new conditions", instigates further investigation of fluid phase behavior and composition, and challenge macroscale reservoir simulation predictions. In this study, the effect of decrease in pore size, as well as higher temperature and pressure conditions, in fluid behavior and composition is studied. Chapter 1 reviews and discusses previous works on geological resources modeling and simulation. With the knowledge acquired, a fully squared shale pore is proposed and applied to study hydrocarbon fluid phase and compositional behavior in organic shale rocks in Chapter 2. Results demonstrate that pores in the nanoscale region tend to increase fluid mass density, which can contribute to phase transition, and heptane composition inside studied pores. The higher fluid density results in an underestimation of reserves prediction by reservoir simulations, when the change in density is not considered.
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Mitsui, Yuta. "Study on relationships between frictional strength and long-term fault behavior including evolution of pore fluid pressure." 京都大学 (Kyoto University), 2011. http://hdl.handle.net/2433/135410.
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Less, David Matthew. "Transient behavior of liquid jets injected normal to a high velocity gas stream." Diss., Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/53887.
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The transient effects of the breakup and atomization of liquid jets in a crossflow on the size of droplets within the spray plume was experimentally determined. Water and water/methanol mixtures were injected normal to a high velocity air stream at Mach numbers of 0.48 and 3.0 with ambient stagnation temperature and respective stagnation pressures of 1.4 and 4.3 atm. The liquids were injected at liquid-to-gas momentum flux ratios ranging from 4 to 12. Droplet size distributions were obtained using a Fraunhofer diffraction technique at sampling rates of up to 9 kHz. Liquid mass flow rates were inferred from measurements of the extinction of a laser beam traversing the plume. The droplet sizes were found to fluctuate with frequencies of the order of 1 to 10 kHz. The fluctuations were characterized by a sudden and relatively brief increase in the mean diameter of the droplets caused by the passage of fractured clumps through the spray plume. Also evident in the droplet size distributions was the very small size of the droplets that had been sheared off the windward surfaces of the jet. The jet fracture frequency was related to the frequency of waves propagating along the initial jet column. The column waves are postulated to have been caused by jet perturbations created by vortices in the air flow around the jet column.Ph. D.
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Brunner, Dominik. "Fast boundary element methods for large-scale simulations of the vibro-acoustic behavior of ship-like structures." Tönning Lübeck Marburg Der Andere Verl, 2009. http://d-nb.info/99703128X/04.
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True, Aaron Conway. "Patchiness: zooplankton behavior in finescale vertical shear layers." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42925.
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Regions containing gradients of vertical flow are often associated with sharp changes in hydrographic and biochemical water properties in coastal marine ecosystems. Often these are sites of dense plankton aggregations of critical ecological importance. In this study, a recirculating flume apparatus with a laminar, planar free jet (the Bickley jet) was used to create finescale gradients of fluid velocity (shear) in both upwelling and downwelling configurations for zooplankton behavioral assays. Particle image velocimetry (PIV) was used to fully resolve the velocity fields allowing us to fine-tune experimental parameters to match fluid mechanical conditions commonly measured in the field. Zooplankton behavioral assays with two tropical calanoid copepods, Acartia negligens and Clausocalanus furcatus, an estuarine mysid, Neomysis americana, and the larvae of an estuarine mud crab, Panopeus herbstii, were conducted in control (stagnant), upwelling, and downwelling flow configurations. Statistical analyses (ANOVA) of individual zooplankton trajectories revealed the potential for individual behavioral responses to persistent finescale vertical shear layers to produce population scale aggregations, which is proposed here as a mechanism of patchiness in coastal marine ecosystems. Results from behavioral analyses reveal species-specific threshold shear strain rates that trigger individual behavioral responses. Furthermore, results show statistically significant changes in behavior (relative swimming speed, turn frequency, heading) for all species tested in response to a coherent shear structure in the form of finescale upwelling and downwelling jets. The results show that changes in individual behavior can increase Proportional Residence Time (PRT = percent time spent in the jet structure). On a population scale, the increase in PRT can lead to dense aggregations around persistent flow features, which is consistent with numerous field studies. These dense, patchy aggregations of zooplankton have profound trickle-up ecological consequences in coastal marine ecosystems.
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Chibwe, Deside Kudzai. "Flow behavior, mixing and mass transfer in a Peirce-Smith converter using physical model and computational fluid dynamics." Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/6798.
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Freedland, Graham. "Investigation of Jet Dynamics in Cross-Flow: Quantifying Volcanic Plume Behavior." PDXScholar, 2016. http://pdxscholar.library.pdx.edu/open_access_etds/3314.
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Volcanic eruption columns inject high concentrations of ash into the atmosphere. Some of this ash is carried downwind forming ash clouds in the atmosphere that are hazardous for private and commercial aviation. Current models rely on inputs such as plume height, duration, eruption rate, and meteorological wind fields. Eruption rate is estimated from plume height using relations that depend on the rate of air entrainment into the plume, which is not well quantified. A wind tunnel experiment has been designed to investigate these models by injecting a vertical air jet into a cross-flow. The ratio of the cross-flow and jet velocities is varied to simulate a weak plume, and flow response is measured using particle image velocimetry. The plumes are characterized and flow data relative to the centerline is examined to measure the growth of weak plumes and the entrainment velocity along its trajectory. It was found that cross-flow recirculates behind the jet and entrainment occurs both up and downstream of the jet. Analysis of the generation of turbulence enhanced results by identifying the transition point to bending plume and the growth of the shear layer in a bending plume. This provides information that can be used to improve models of volcanic ash concentration changes in the atmosphere.
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Bruckner, Robert Jack. "Simulation and Modeling of the Hydrodynamic, Thermal, and Structural Behavior of Foil Thrust Bearings." Case Western Reserve University School of Graduate Studies / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=case1089304186.
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Cheng, Chieh-Wen, and 鄭捷文. "Investigation of magnetic fluid droplet behavior." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/03484987880030389841.
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碩士中國文化大學
機械工程學系數位機電碩士班
101
Research thrust of this article is the contact angle using magnetic fluid droplet shape measurement，droplet image quality and analysis droplet shape the program decided to contact angle。Analysis program from the droplet boundary detection and droplet shape analysis to identify contact angle。Then observed by the change applied magnetic field, magnetic fluid droplets and in in external magnetic field change change of contact angle，Last using Matlab program to meet real image of the droplet boundary gradient method ，use drop shape analysis derived contact angle， compare the magnetic fluid by magnetic field changes size 。