Scaling of inner and outer regions for flat plate boundary layers

Abstract

A new view of the scaling of the streamwise turbulence intensity profile is proposed for the zero pressure gradient turbulent boundary layer. The method is based on the scale decomposed streamwise velocity component, separated into a small- and a large-scale contribution using a wavelength pass-filter. This enables us to understand how large and small scale motions affect the streamwise turbulence intensity profile. It is found that the small-scale energetic content collapses remarkably well over a large range of Reynolds number (2800 ≤ Re τ≤ 19000). On the other hand, the large-scale energetic content does not simply collapse in inner, outer or mixed scaling, but a clear peak emerges, which..