Title: Towards a Physical Scale Decomposition of Mean Skin Friction Generation in the Turbulent Boundary Layer
Abstract: A decomposition of mean skin friction generation in zero-pressure-gradient boundary layers is presented, relying on an energy budget in an absolute reference frame. It has a direct physical interpretation and emphasizes the importance of the production of turbulent kinetic energy in the logarithmic layer in mean skin friction generation at very high Reynolds number. This leads to a new approach to the scale decomposition of mean skin friction, illustrated using a Wall-Resolved LES at $$Re_\theta $$ = 13,000 obtained by the ZDES technique. The role of superstructures is especially discussed.