مدل سازي عددي حركت اجسام در سيال با استفاده از شبكه بولتزمن و برهمكنش سيال و سازه

چكيده انگليسي :

Simulation of Moving Body in Field Flow and Fluid Structure Interaction with using Lattice Boltzmann Method Ehsan Goraki Fard e gorakifard@me iut ac ir Date of Submission 15 5 2010 Department of mechanical engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Ebrahim Shirani eshirani@cc iut ac ir Abstract In recent year lattice Boltzmann method LBM which is obtained from kinetic theory has advanced numerously It is good and efficient method for solving fluid flow equation at low Mach number In other hand fluid structure interaction problems which are very applicable in various fields in industry and medical application is interested very much In this paper LBM is used to simulate fluid flow based on Eulerian grid and finite element is used for solid structure based on Lagrangian approach These methods are coupled for simulation of fluid structure interaction In our simulation force which is created by fluid is applied to the solid structure and then fluid field is changed by deflection of structure It is noticeable that interaction is accrued between interfaces The explicit coupling method for simulation of fluid structure interaction in large deformation is introduced that in this method has been used of two separated solver for solid and fluid part The lattice Boltzmann approach has to be categorized as an embedded approach as it is based on fixed Cartesian grids Local refinement can be achieved e g by using quad type grids The extra computational cost for handling moving geometries over the fixed grid is due to the computation of link distances to the moving boundaries and restricted to a region close to these boundaries Multiple relaxation time MRT models is used for increasing computation accuracy at high Reynolds number Oscillation of cantilever beam because of internal and external force which has been attached to a cylinder has been studied in this thesis The LB solver has been coupled with a transient solid structure solver based on one dimensional beam elements The model is an Euler Bernoulli beam and the finite element discretization is based on isoperimetric Hermit elements with nodal displacements and slopes as independent degrees of freedom For the time integration a Newmark scheme and a modal analysis has been used Our goal is to investigate the validity and efficiency of coupling the two approaches to simulate transient bidirectional Fluid Structure interaction problems with geometrically non linear structural deflections We describe in detail the force evaluation techniques displacement transfers and the algorithm used to couple these completely different solvers Diagram of displacement versus time for several of interaction problems is shown and is compared with computational method results and it is seen that there are good agreements between the results The results show the ability of LBM for simulation of fluid structure interaction The application of this project can be used in micro channel at two phase flow as mixer and fans in computer devices Keywords Lattice Boltzmann Method Fluid Structure Interaction Finite Element Coupling Algorithm

گوركي فرد، احسان

مدل سازي عددي حركت اجسام در سيال با استفاده از شبكه بولتزمن و برهمكنش سيال و سازه

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