Ritz Ri

The simplest way to apply a wall shear stress boundary condition in a cylindrical coordinate system is to convert the wall shear stress into components in the radial and axial directions. The radial component should be zero since shear stress has no effect on the radial direction in a cylindrical coordinate system. The axial component can be calculated from the wall shear stress using the equation:

Axial Shear Stress = Wall Shear Stress x cos(angle between wall normal and axial direction).

Once the axial shear stress is determined, it can be applied to the boundary condition in the axial direction.