绕方柱流速度场的数值模拟

采用有限差分法 ,对雷诺数为 2 .2× 10 4 的三维绕方柱流的速度场进行了大涡模拟。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而非通常采用的WallDampingFunction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的计算结果与文献上的实验结果进行了比较 ,结果吻合较好。

Numerical Simulation of Velocity Field of Flow Around Square Cylinder

Using the large eddy simulation (LES) and the finite difference method, a three dimensional simulation of the velocity field of flow around a square cylinder at a Reynolds number of 22 000 is conducted. The N S equation is split into advection step, diffusion step and propagation step with the time split operator. The near wall effect is treated by using two layer model, rather than the usually employed wall damping function. The convection term is discretized with upwind central difference scheme, and the pressure equation is solved by successive over relaxation (SOR) method. The computed mean velocity along the symmetry line is compared with experimental results reported in literatures. They are in good agreement with each other.