Energy cascade and vortex structure in turbulent channel flow

Abstract

The energy transport in the scale space in turbulent channel flow was examined to show that the inverse cascade is seen in the spanwise part of turbulent energy. In order to understand the flow structure associated with the inverse cascade, the conditional average of velocity field was evaluated in relation to the negative energy production. The profiles of the conditional average showed that the two streamwise vortices are seen near the region of the negative production. The downward flow impinging toward the wall enhances the spanwise grid-scale velocity components, resulting in the inverse cascade of the spanwise energy.