[qingqingliu]

I set up a 2D axisymmetric geometry with 1 degree in OpenFOAM. The front and back patches are usually set "wedge". In my simulation, I set part of the front and back patches to "slip" condition, and the remaining front and back patches are set "wedge". The normal component of the velocity with the slip condition should be zero. However, in the simulation results, the normal component of the velocity is not zero at the patch where "slip" boundary condition is applied. I do not find the reason. Perhaps, there is only one layer of grid cell in the direction of front and back patches, the slip condition does not work as expected? Does anyone know the reason?