Wall-wake laws for the mean velocity and the turbulence

Abstract

A new wall-wake law is proposed for the streamwise turbulence in the outer region of a turbulent boundary layer. The formulation pairs the logarithmic part of the profile (with a slope A_1 and additive constant B_1) to an outer linear part, and it accurately describes over 95% of the boundary layer profile at high Reynolds numbers. Once the slope A_1 is fixed, B_1 is the only free parameter determining the fit. Most importantly, B_1 is shown to be proportional to the wake factor in the wall-wake law for the mean velocity, revealing a previously unsuspected connection between the turbulence and the mean flow.