TURBULENCE MODIFICATION IN A STABLY-STRATIFIED CHANNEL FLOW

摘要

The influence of stable stratification in boundary-forced turbulent flows is studied in the prototypical case of channel flow using large eddy simulations. As stratification increases, active wall-bounded turbulence with reduced vertical transport coexists with internal wave activity in the core of the channel. Results obtained to characterize buoyancy effects include skin friction, Nusselt number, profiles of vertical momentum and buoyancy fluxes, turbulence intensities, gradient Richardson number. The study has evidenced that, similar to unbounded stratified turbulence, the gradient Richardson number seems the most appropriate parameter to characterize wall-bounded stably-stratified flows.