An Improved Immersed Boundary Lattice Boltzmann Method And Application In CFD

Lattice Boltzmann method(LBM) and immersed boundary method(IBM) are gaining researchers' extensive attention in CFD field for the simplicity, efficiency on dealing with fluid field and convenience on deal the fluid-solid boundary respectively. In the past ten years, scholars have brought immersed boundary lattice Boltzmann method(IB-LBM) by combined the advantages of both methods. In this paper, it focuses on the researching on the theory of IB-LBM and improving of calculation model. The features of improve method are analyzed through numerical simulation. And some applications are adopted in the related chapters. The contents of the thesis are followed:An improved immersed boundary lattice Boltzamann method is brought about. The improved method has adopted the force model of lattice Boltzmann model, simplified the calculation process of fluid-structure force and improved the efficiency of calculation. Compared with the original approach, there are no iteration steps in deal with the force on fluid structure interaction. In this way, it can make sure that the stream line is symmetric and the calculation progress is stable for flow over a cylinder at low Reynolds. Simultaneously, the simulations results show that this one can save near half time for the same calculating model. Through steady and unsteady flow over a cylinder simulation, the results are demonstrated very similar to those analytical solutions in the references which mean the validity of the method is verified.The problems of flow around the rotating cylinder at Re40, 200 are studied based on the improve method. Comparing the fluid dynamic parameters with the references, the result shows that the length of recirculation zone is declining with the increasing of rotating ratio. And the results verified that the lift coefficient and drag coefficient vary linearly. The results can support the further study of hydrodynamic of liquid membrane in bearings.Based on the IB-LBM, it has combined the subgrid model of large eddy simulation to study the turbulence in two dimensions. The flow around cylinder model at lower Reynolds is brought to check the reliability of the combined method. The related parameters of higher Reynolds are analyzed with reference, which show that the value on the large eddy simulation. It provides a available simulating model for the research on turbulence.