7259

6765

كارشناسي ارشد

تبديل انرژي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك

1391

يازده، 102ص: مصور، جدول، نمودار

ص.ع به فارسي و انگليسي

ابراهيم شيراني

محمود اشرفي زاده

21/8/91

احمد صابونچي، مهدي نيلي احمدآبادي

1396/09/21

كتابنامه

مكانيك

مهندسي مكانيك

ID6765

به فارسي و انگليسي: قابل رويت در نسخه ديجيتال

Lattice Boltzmann Method for Simulating of Pulsative Blood Flow in Distensible Blood Vessels and Investigation of the Effect of Flow Parameters on the flow Hamed Shahin h shahinvarnosfaderani@me iut ac ir Date of Submission 2012 09 20 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Ebrahim Shirani eshirani@cc iut ac irAbstractSpread of atherosclosis illness in aorta causes many problems in blood circulating Hemodynamic factorsperform an important role in this illness Hence making an effective coupling between fluid and structure incontinuous pulse modes is the main challenge In recent years the lattice Boltzmann Method LBM whichis obtained from kinetic theory has been advanced numeritically It is a simple numerical method which hassome advantages such as easy implementation highly desirable for parallel computing and second orderaccuracy It is a proper and efficient method for solving fluid flows at low Mach numbers The purpose ofthis project is to simulate pulsatile blood flow in flexible vessels From the theoretical point of view FluidStructure Interaction problems is extremely difficult because of the high non linearity of the governingequations and the low regularity of the displacement of the fluid structure interface The fluid equations aresolved by lattice Boltzmann method and the structure equations are solved by dynamic finite elementmethod by Fortran programming We used explicit 2 way coupled method for coupling of the fluid wallinteractions and then applied the force created by fluid to the solid structure domain Then displacementsand velocities at the wall are calculated from the solid part and used for the fluid We used two separatesolvers for solid and fluid parts Solid has been considered as axisymmetric and linear elastic substancewith fixed constraint at inlet and outlet Proportional damping is applied for simulation of solid damping The implicit Newmark method is used for time integration The fluid model that used in lattice Boltzmannmethod is a two dimentional and Newtonian model In this study laminar flow was assumed In this project the effect of elasticity of vessel wall on velocity profile and shear stress has been evaluated in different inletand outlet boundary conditions The inlet velocity and outlet pressure boundary conditions are used in thesimulations At first stage the differences between flexible and rigid states have been considered atconstraint of constant inlet velocity and outlet pressure Then the effect of pulse inlet velocity has beenstudied The effect of various damping of vessel wall on results has been considered The results show theability and strength of LBM for simulation of fluid structure interaction We compared the velocity profilesof two different states first when we consider positive acceleration at inlet and constant pressure at outlet second negative acceleration at inlet and constant pressure at outlet The comparison showed that velocityprofile becomes smoother at the first state than later The simulations show that the velocity profile is moreuniform for the flexible state and so the shear stress in this state reduces Finally pulsative inlet pressureand constant outlet pressure have been considered where damping affects results more than it did in theprevious case Moreover the less the damping is the flatter the velocity profile becomes Keywords Lattice Boltzmann Method blood Finite Element Fluid Structure Interaction

ابراهيم شيراني

محمود اشرفي زاده

احمد صابونچي، مهدي نيلي احمدآبادي