[sek]

Has anyone had luck with wall shear stress calculation with OpenFOAM with RANS? First, let me say that I'm not using wall functions - my near wall mesh is around y+=1. We're using Spalart-Allmaras model. And we get an incredibly small wall shear stress, a few order of magnitude smaller than what it should be.

The WallShearStress utility computes the wall shear from the inner product of the wall normal and stress tensor (R). For all the turbulence models I've seen in OF, R is computed using "turbulent" viscosity (nut) and the velocity gradient, which is a bit surpprising to me. I suppose nuEff be used instead?

Since I'm not using wall function, I presume that OF does not mess up with nut, which would become very small in viscous sublayer and nutdU.dy is NOT the wall shear stress! can someone enlighten me?