Turbulent Structure in Horizontal Channel Flow under Unstable Density Stratification

Abstract

Direct numerical simulations are performed for a fully-developed horizontal channel flow under unstable density stratification. Moreover, to investigate the effects of the penetrative thermal plumes and counter-gradient heat flux on near-wall turbulence, the ad-hoc calculations are car­ried out, in which the buoyancy force acts only conditionally, depending on the local state of the turbulent heat flux.