Abstract
We carried out direct numerical simulation on turbulent flow over wavy walls, which mimic the skin folds of fast-swimming dolphins. We changed the amplitude and the angle of ridgelines of the wavy wall. The computational results show a decrease of 6.0 % in the total shear stress at the wall in the case of A^+ = 6 and γ = 0 degrees. The regions of high - and - low wall - shear stress becomes smaller in the case of the angled wavy wall than that in the case of the simple wavy wall. This is due to the secondary flow along the valley.