亚临界雷诺数下圆柱和方柱绕流数值模拟

Numerical simulation of the flow around circular and square cylinder at sub-critical Reynolds numbers

基于RNG k-ε模型,采用有限体积法对亚临界雷诺数条件下（Re=3×102～3×105）的二维单圆柱和单方柱绕流进行数值模拟与仿真。得到了圆柱和方柱绕流阻力系数Cd与Strouhal数随雷诺数的变化规律。同时对雷诺数Re=22 000下的圆柱、方柱绕流相关特性进行详细对比分析。计算结果表明：同一雷诺数下,单圆柱绕流阻力系数Cd较单方柱低,但圆柱的Strouhal数较单方柱则要高。虽然二者边界层分离点不同,但流场的演变与漩涡的脱落具有一定相似特性。

With the RNG κ-ε model and the finite volume method,the flow around a two-dimensional circular cylinder and a two-dimensional square cylinder at sub-critical Reynolds numbers was simulated and evaluated,and the trends of drag coefficients and Strouhal numbers with the change of Reynolds numbers from 3×10～2 to 3×10～5 were obtained.Meanwhile,characteristics of the flow around a circular cylinder and a square cylinder at Re=22 000 have been compared and analyzed in detail.Calculation results show that drag coefficient of flow around a circular cylinder is lower than the drag coefficient of flow around a square cylinder with the same Reynold number.However,the Strouhal number of flow around a circular cylinder is slightly higher than the Strouhal number of flow around a square cylinder.Though their boundary layer separation points are different,the flow field evolution and the vortex shedding of two cylinders have some similarities.