Numerical investigations of heat transfer mechanisms in the forced laminarwall jet

The effect of high-amplitude forcing on a laminar wall jet over a heated fl at plate is analysed. Highly accurate direct numerical simulations (DNS) ar e used to investigate the dominant transport mechanisms. When forcing is ap plied, the skin friction is reduced markedly and the wall heat transfer is increased. Detailed examination of the unsteady flow field showed that the concepts of eddy viscosity and eddy thermal diffusivity, usually applied to turbulent flows, can be applied to the analysis of unsteady laminar flows to explain the effect of highly unsteady phenomena.