改进的格子涡方法及其在混合层模拟中的应用

在格子涡方法中 ,用网格节点处的流场速度通过插值确定离散涡元速度时 ,往往会导致很大误差 ,为此 ,给出了一种改进的格子涡方法。在该方法中 ,每个时间步开始时 ,离散涡元被置于网格节点上 ,它们以网格节点处的流场速度运动 ,而在该时间步结束时 ,将偏离网格节点位置的离散涡元用涡量再分配的方法重新置于网格节点上 ,这样离散涡元总是以网格节点处的流场速度运动 ,避免了插值及其所导致的误差。对混合层流动的模拟结果表明对格子涡方法的改进是成功的。

Improved VIC method and its application on the simulation of mixing layer flow

In the vortex in cell (VIC) method, error is induced by the interpolation used to determine the velocities of the discrete vortex elements from the velocities of the flow field on the grid nodes. An improved VIC method was proposed with the discrete vortex elements at the beginning of each time step located on the grid nodes and then moving with the local velocity of the flow field. At the end of each time step, the discrete vortex elements that moved away from the grid nodes are relocated back to the grid nodes using the vorticity reassignment method. Thus, the discrete vortex elements always move with the flow velocity, avoiding interpolations and resulting errors. The numerical results for mixing layer flow show that the improvement is successful.