Turbulence and internal waves in a stably-stratified channel flow

Abstract

Direct numerical simulations (DNS) of stably-stratified, turbulent channel flow at moderate Reynolds number are currently being performed on the XC-4000. A wide range of stratification levels is being considered and large computational boxes are being employed to study carefully the effects of stratification on the wall turbulence. First and second order statistics are discussed. The characteristics of the flow are elucidated using instantaneous snapshots of velocity and density fluctuations. It is shown that, for high stratification levels, the flow remains turbulent close to the walls while internal gravity waves dominate the core of the channel.