基于黏性涡域法的二维钝体绕流模拟

Simulation of flow around two-dimensional blunt body based on the viscous vortex domain method

针对传统计算流体力学方法需要划分网格且计算耗时长等问题,一种确定性涡方法(黏性涡域法)逐渐发展并日臻成熟。本文利用该方法计算模拟了二维钝体的流场、气动系数及斯特劳哈尔数,并与其他成熟CFD软件计算结果对比来验证模拟精度。黏性涡域法的模拟过程为生成涡量、涡量演变及气动计算。文章首先推导了该方法各过程的基本方程,然后基于Lua语言编制了圆柱和方柱绕流计算程序,最后利用Gnuplot实现流场可视化。利用黏性涡域法模拟不同雷诺数下圆柱绕流、不同无量纲频率和无量纲振幅的振动圆柱气动力时程、不同风向角下的方柱绕流,结果表明:雷诺数为2×10^(2)~1×10^(5)时,基于黏性涡域法的圆柱绕流气动计算结果与其他方法的计算结果基本一致;基于该方法的不同风向角下方柱绕流气动计算结果与其他文献结果趋势相同。

The mesh generation is indispensable for traditional CFD methods,but it usually takes a long time,especially for complex geometries.By comparison,the mesh-free viscous vortex domain(VVD)method is getting increasingly more attention for flow field simulation and has undergone significant development recently.This paper first verifies the accuracy of VVD by simulating the flow field around a bluff body section and comparing the results with those of other CFD methods.Then,the governing equations for the three steps of VVD,vorticity generation,vorticity evolution,and aerodynamic calculation,are derived,based on which a flow field calculation program is developed using Lua language.Finally,use Gnuplot to visualize the flow field.VVD is used to simulate flow fields around a circular cylinder at different Reynolds numbers,the aerodynamic histories of a vibrating circular cylinder at different dimensionless frequencies and amplitudes,and the flow fields around a rectangular cylinder at different wind angles.Results show that when the Reynolds number is between 2×10^(2)and 1×10^(5),the flow fields around a circular cylinder obtained on the VVD method are consistent with those of other methods.Moreover,the aerodynamics of a rectangular cylinder with different wind angles based on this method have the same trend as those reported in previous studies.