Large-scale structures in a stratified open channel flow

Abstract

Abstract. We present the results of direct numerical simulation of stably stratified open channel flow. The simulation was conducted in a frame of reference moving with the mean flow. The chosen setup allowed us to apply temporal filtering without affecting the long-living large-scale laminar and turbulent patches to see the dynamics of the processes on their boundaries. The main goal of the paper was to investigate the vorticity balance in different parts of the flow. It was shown that boundaries between laminar and turbulent patches contain weak large-scale vortex structures sustained by the baroclinic generation.