After checking the problematic areas the only things that seem to coincide with the awful wallshearstress distributions are the lowQualityTetFaces, which are clustered around the bad areas. And also the UnderdeterminedCells, which seem to be very consistently all the boundary layers below the 8th layer counting from the wall. But I doubt its the underdeterminedCells as these are also in areas where the simulation is running totally fine. @Snail With a Shotgun Have you experienced anything similar?