方柱绕流的数值模拟

Numerical Simulation of Flow around Square Cylinder

采用有限差分法,对雷诺数为2.2×104的方柱绕流进行了大涡模拟(简称LES).运用时间分裂控制(Split-Operator)法,将N-S方程分为对流步、扩散步和传播步.对Smagorinsky假设在近壁区的发散问题用两层模型进行处理.对流项用迎风-中心差分格式模拟,压力方程用SOR法迭代求解.计算得到的沿对称线的时均顺流向速度与文献上的实验结果进行了比较,结果吻合较好;同时还对绕方柱流的流场结构进行了分析研究.

Using the large eddy simulation (LES) and finite difference scheme, three-dimension simulation of the velocity field around a square cylinder at a Reynolds number of 22,000 is conducted. The so-called split-operator that split N-S equation into adverction step, diffusion step and propagation step is employed. The near wall effect is considered by using two-layer model, no rather normal used wall damping function. The convection term is discretized with upwind-central difference scheme, while the pressure e-quation is solved by SOR. The computed mean velocity along the symmetry line and the aerodynamic forces are compared with experimental results. The results are in agreement with the experimental results.