Thank you for reply.
My model size is 2m × 0.5m × 0.125m and the number of grids is 835 × 110 × 70. The x-direction is the flow direction and the y-direction is the spanwise direction. The spanwise direction uses periodic boundary conditions and the y+ in the z-direction is about 1.0. The grids in the other two directions are evenly distributed.