Influence of inflow disturbances on stagnation-region heat transfer

Numerical simulations of laminar stagnation-region heat transfer in the pre sence of freestream disturbances are performed. The sensitivity of heat tra nsfer in stagnation-region to freestream vorticity is scrutinized by varyin g the length scale, amplitude, and Reynolds number. As an organized inflow disturbance, a spanwise sinusoidal variation is superimposed on the velocit y component normal to the wall. An accurate numerical scheme is employed to integrate the compressible Navier-Stokes equations and energy equation. Th e main emphasis is placed on the length scale of laminar inflow disturbance s, which maximizes the heat transfer enhancement. Computational results are presented to disclose the detailed behavior of streamwise vortices. Three regimes of the behavior are found depending on the length scale: these are the "damping," "attached amplifying," and "detached amplifying" regimes, re spectively. The simulation data are analyzed with an experimental correlati on. It is found that the present laminar results follow a general trend of the correlation.