Conditional large-scale structure of a high Reynolds number turbulent boundary layer

Abstract

A spanwise array of 10 surface mounted hot-film shear-stress sensors coupled with a traversing hot-wire probe are used to identify the conditional structure associated with a large-scale skin-friction event in a high Reynolds number turbulent boundary layer (Re τ ≈ 14000). Instantaneous shear-stress data indicate the presence of large-scale structures at the wall that are comparable in scale and arrangement to the superstructure events as reported previously by Refs (4; 5). Conditional averages of streamwise velocity computed based on a low skin-friction footprint at the wall offer a wider three-dimensional view of the average superstructure event. These events consist of highly elongated fo..