方柱绕流的大涡模拟

采用物理分步法对方柱绕流的流动分离现象进行了大涡模拟(LES).物理分步法将N-S方程剖分为对流、扩散及波动过程,对不同的物理过程分别采用适宜的方法进行求解.对流过程采用逆风——中心差分格式求解;扩散过程采用中心差分格式求解;压力方程采用SOR迭代法求解.计算的方柱四周的平均压力系数的分布与物理模型试验结果吻合良好;模拟的流动现象也得到了物理模型试验的证实.

Large Eddy Simulation of Flow Around a Square Cylinder

Large eddy simulation cooperated with the physical fractional-step method is applied to simulate the flows around a square cylinder.The basic idea of this physical fractional-step method is that the water governing equations(N-S equations) is separated into three parts according to the behavior of each differential operator.The first is a convective problem,and solved by the central-upwind deference scheme;the second is a diffusive problem,and solved by the central deference scheme;and the third is a source term(pressure equation),and solved by the SOR iteration method.Comparisons of the calculated mean pressure coefficient distribution around the square cylinder and experimental data are in agreement,and the imagine map of vortices by LES method is proved by experimental results.