1308 Numerical simulation of spatially developing turbulent boundary layer for friction drag reduction by wall surface-heating

Abstract

Direct numerical simulation of a spatially developing boundary layer is performed with uniform wall-heating or wall-cooling aiming at friction drag reduction. The Boussinesq approximation is adopted for the buoyant force. The Richardson number, Ri, is set to be 0.01 for wall-heating and -0.01 for wall-cooling. It is found that the uniform wall-cooling has drag reduction effect, while wall-heating leads to drag enhancement. The former is due to reduction of Reynolds shear stress -<v'v'>^^^- by stabilizing of the turbulent flow with wall-cooling.