层流平板摩擦阻力的数值计算

为提高层流摩擦阻力数值计算的精度,采用数值求解N-S方程的方法,对层流平板摩擦阻力进行了计算.计算中采用4种先进上风格式,同时配合以14种不同的壁面法向网格分布和5种常用限制器,并将计算结果与布拉修斯解进行对比.结果表明,van Leer的FVS(Flux Vector Splitting)格式数值耗散大,对网格分布和限制器敏感,不适合用于摩擦阻力计算.限制器和计算格式的粘性分辨率越高,摩擦阻力的计算精度越高.在计算量允许的情况下,可以减小壁面法向第1层网格高度,以提高计算精度,但应同时兼顾网格长宽比.对于摩擦阻力计算,边界层内应至少布置4个网格点. 

Numerical calculation of laminar flat plate skin friction

In order to calculate laminar skin friction more accurately, the laminar flat-plate skin friction was calculated by solving the N-S equations. For solving the N-S equations, 4 advanced upwind schemes, 14 different grid distributions and 5 limiters were employed. All the results were compared with Blasius solution. The results show that the van Lee′s FVS(flux vector splitting)scheme has considerable numerical dissipation, it is also sensitive to grid quality and limiter, so it is unsuitable for friction calculation. The solution is more accurate with a higher limiter and scheme viscous resolution. The calculation precision strongly depends on the height of the first level mesh. Considering both of the calculation ability and the grid aspect ratio, the height of the first level grid can be reduced to improve precision. For skin friction calculation, there must be no less than 4 grid points in the boundary layer.