The objective of this thesis was to assess the validity of the fluid-structure interaction (FSI) facilities in LS-DYNA for the analysis of highly deformable structures interacting with flowing viscous fluids. The collapsible tube experiment was chosen as a validation tool for FSI since its three-dimensional computational modelling would have been impossible if the viscous internal fluid flow were not considered. An explicit three-dimensional finite element model of a collapsible-tube was constructed and solved using LS-DYNA. The fully coupled model included internal fluid flow; external, inlet and outlet pressures; tube wall tension; pre-stressing; and contact. The finite element boundary conditions were taken as the recorded values of flow rate and pressure from a standard collapsible-tube experiment for both steady and unsteady flows. The predicted tube geometry in the steady LS-DYNA model showed good agreement with the experiment for operating points in the highly compliant region of the pressure-flow characteristic curve. The comparative position of the pinch at the outlet end differed by only 5.6% of the outlet diameter in the worst case. This analysis represents an advance on other published work in that previously no comparison with experiments have been drawn for FSI models involving high Reynolds number flowing viscous fluids interacting with highly deformable three dimensional structures. This analysis successfully made that comparison and the experimental and computational results have combined to form a more detailed picture of the collapsible-tube phenomenon by including detailed stress results of the tube walls and views of the internal fluid flow. The collapsible tube model exhibited uncertainty errors due to the use of a coarser than desirable mesh and a reduced fluid speed of sound. Although both these approximations caused significant error in the model both were necessary in order to achieve acceptable solution times. Because of these errors a thorough quantitative validation could not be achieved although LS-DYNA has been proven to be qualitatively accurate. Increases in computing speed are required before thorough quantitative validation of FSI can be achieved by comparison with the collapsible tube experiments.

Finally, we investigate the motion of a general form rigid body with smooth boundary by an incompressible perfect fluid occupying R3 . Due to the domain occupied by the fluid depending on the time, this problem can be transformed into a new systems of the fluid in a fixed domain by the frame attached with the body. With the aid of Kato-Lai's theory, we construct a sequence of successive solutions to this problem in some unform time interval. Then by a fixed point argument, we have proved that the existence, uniqueness and persistence of the regularity for the solutions of original fluid-structure interaction problem. / In the first part, we study the issue of the inviscid limit of the incompressible Navier-Stokes equations on the general smooth domains for completely slip boundary conditions. We verify an asymptotic expansion which involves a weak amplitude boundary layer with the same thickness as in the Prantle's theory. We improve the better regularity for the boundary layer and obtain the uniform Lp--estimates (3 < p ≤ 6) of the remainder. Then we improved these estimates to H 1--estimates. It is shown that the viscous solution converges to the solution of Euler equation in C([0, T]; H1(O)) as the viscosity tends to zero. / In the second part, we consider the non-stationary problems of a class of non-Newtonian fluid which is a power law fluid with p > 3nn+2 in the half space with slip boundary conditions. We present the local pressure estimate with the Navier's slip boundary conditions. Using these estimates and an Linfinity -- truncation method, we can obtain that this system has at least one required weak solution. / In this thesis, we study several issues involving incompressible viscous fluids with the slip boundary conditions and the motions of fluid-solid interactions. / Zang, Aibin. / Adviser: Zhouping Xin. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 128-141). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Duan, Ben. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 61-67). / Abstracts in English and Chinese. / Acknowledgments --- p.2 / Abstract --- p.i / Introduction --- p.3 / Chapter 1 --- Stability of Shock Waves in Viscous Conservation Laws --- p.10 / Chapter 1.1 --- Cauchy Problem for Scalar Viscous Conservation Laws and Viscous Shock Profiles --- p.10 / Chapter 1.2 --- Stability of Shock Waves by Energy Method --- p.15 / Chapter 1.3 --- L1 Stability of Shock Waves in Scalar Viscous Con- servation Laws --- p.20 / Chapter 2 --- Slow Motion of a Viscous Shock --- p.29 / Chapter 2.1 --- Propagation of a Viscous Shock in Bounded Domain --- p.29 / Chapter 2.1.1 --- Steady Problem --- p.30 / Chapter 2.1.2 --- Time-Dependent Problem --- p.34 / Chapter 2.1.3 --- Super-Sensitivity of Boundary Conditions --- p.36 / Chapter 2.2 --- Propagation of a Stationary Shock in Half Space --- p.39 / Chapter 2.2.1 --- Asymptotic Analysis --- p.39 / Chapter 2.2.2 --- Pointwise Estimate --- p.40 / Chapter 3 --- Viscous Transonic Flow Through a Nozzle --- p.47 / Chapter 3.1 --- Nonlinear Stability and Instability of Shock Waves --- p.48 / Chapter 3.2 --- Asymptotic Stability and Instability --- p.49 / Chapter 3.3 --- Matched Asymptotic Analysis --- p.53 / Chapter 4 --- C --- p.60 / Bibliography --- p.61

Thesis (M. Phil.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 112-114).

published_or_final_version / abstract / toc / Mechanical Engineering / Master / Master of Philosophy

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