Scale by scale budgets for PIV and DNS data of wall-bounded turbulence

The dynamics of the wall region at different scales recently has been analyzed for DNS of a channel at small Reynolds number through a generalized form of the K\'{a}rm\'{a}n-Howarth equation. The present work analyzes the scale-by-scale dynamics of wall-bounded flows at higher Re using both experimental and numerical data. The former data are taken from a dual-plane PIV experiment (that allows evaluation of the entire velocity gradient tensor) performed in a zero-pressure-gradient turbulent boundary layer at friction Reynolds number $Re_\tau = 1160$. The numerical data are taken from DNS of a turbulent channel flow by Zandonade and Moser, realized at a comparable $Re_\tau = 950$. Wall-normal locations in the log and wake regions were analyzed. In the log region, both data sets show the existence of a large-scale production range, followed by a nearly classical transfer range, closed by diffusion at the local dissipative scales. In the wake region the turbulent fluctuations are sustained by the spatial flux of scale-energy, while the local production plays a minor role.