Statistical evidence of an asymptotic geometric structure to the momentum transporting motions in turbulent boundary layers

Abstract

The turbulence contribution to the mean flow is reflected by the motions producing the Reynolds shear stress ((- uv}) and its gradient. Recent analyses of the mean dynamical equation, along with data, evidence that these motions asymptotically exhibit self-similar geometric properties. This study discerns additional properties associated with the uv signal, with an emphasis on the magnitudes and length scales of its negative contributions. The signals analysed derive from high-resolution multi-wire hot-wire sensor data acquired in flat-plate turbulent boundary layers. Space-filling properties of the present signals are shown to reinforce previous observations, while the skewness of uv sugges..