Separation and Reattachment in Transonic Airfoil Flow

Abstract

Results are presented of four research programs concerned with the phenomenon of shock boundary-layer interaction and ways that such interactions affect scaling of transonic airfoil flows. The results were obtained using a diverging nozzle and several simulated airfoil contours. Main variables of these programs were the freestream Mach number, the Reynolds number, the mode of boundary-layer transition, and the geometry and location of boundarylayer tripping devices. Emphasis in presenting the results is placed on the flow development that may lead to large transonic scale effects and on the dependency of this development on the unit Reynolds number and the initial boundary-layer condition. An attempt is made to relate components of the shock boundary-layer interaction, i.e., the pressure rise to shockinduced separation, the length of the separation bubble, and the extent of rear separation to parameters associated with the boundary-layer condition upstream of the shock.