基于格子Boltzmann方法和有限体积法的方柱绕流特性对比分析

A Comparative Analysis of Lattice Boltzmann and Finite Volume Methods for Flow over a Square Cylinder

基于黏性流体理论,分别采用格子Boltzmann方法(LBM)和有限体积法(FVM)建立了黏性流场中方柱绕流模型。探究LBM在非光滑曲面钝体绕流方面的应用;并结合FVM进行对比分析。在FVM模型中,采用局部加密的方法对钝体边界进行处理,而在LBM模型中,除了传统的Half-way边界处理方法,还结合了拐角边界处理方法。为获得较好的可对比数据,根据已发表文献中的理论及UDF编译码技术,分别对两模型的进出口边界条件进行了讨论和设置。对比分析了两模型下的速度云图以及获得的升、阻力系数,Strouhal数。结果发现方柱上游压力不受涡脱落影响,雷诺数对其影响也较小;两种方法下的速度、无量纲参数吻合较好;但两者最适进出口边界不同,且相同条件下,LBM比FVM数值模拟能更快达到稳定状态。

Based on the theory of viscous fluid,the flow around square cylinder was modeled using two methods of lattice Boltzmann and finite volume. The method of LBM was discussed about its application and compared with FVM. Boundary conditions was processed with local mesh refinement in FVM model,but methods with Half-way and corner treatment in LBM model. In order to get credible data,two types＇ boundary conditions of inlet and outlet were discussed and set separately according to theory and UDF program. The velocity contour,lift and drag coefficients and Strouhal number of two models are analyzed comparatively. Results found upstream pressure free from vortex shedding,little relations with Reynolds. Two different methods had a great agreement in velocity and non-dimensional parameters,but fittest inlet and outlet boundary. And LBM simulation can achieve stable state very quickly at the same condition.