The wall shear stress, , is given by: Where is the dynamic viscosity, is the flow velocity parallel to the wall and is the distance to the wall. The SI unit of wall shear stress is pascal ( ), which is identical to . The skin friction coefficient, , is defined by: Where is the local wall shear stress , is the fluid density and is the free-stream velocity (usually taken ouside of the boundary layer or at the inlet). Incompressible Flow Laminar In OpenFOAM, wallShearStress usually is in "kinematic pressure", namely in "m2/s2". It doesn't take into account the density of the fluid. So, you should multiply by rho to reach tau. tau = (wallShearStress) * rho or with wallGradU utility tau = (wallGradU) * mu You can use the Calculator filter in ParaView to multiply the "wallShearStress" field by the density value. Turbulence Compressible Flo...
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