Abstract

Turbulent boundary layers are traditionally considered in terms of an inner and outer region, not excluding the logarithmic region, which is usually identified with an overlap of the two regions. Recent experiments in high Reynolds number flows have revealed that the key to understanding the scaling behaviour of the turbulence statistics lies in unravelling the influence and interaction of the outer and inner regions. In this talk a model for the influence of the large-scale motions in wall turbulence (termed superstructures) on the inner viscous region is presented. The model has implications for predicting wall-shear stress fluctuations based on a filtered velocity signature in the outer part of the boundary layer, as required in high Reynolds number large-eddy simulations.