Influence of surface sublimation on supersonic flat plate boundary layer stability

Abstract

Theoretical study on the properties of a supersonic boundary layer and its stability under conditions of surface material sublimation has been performed. Linear stability theory (LST) computations were performed for an adiabatic flat-plate boundary layer with a naphthalene coating at a free-stream Mach number of M=3. Surface sublimation generates in the boundary layer a binary mixture flow of air and foreign vapors. This flow is studied using self-similar boundary layer equations. It was established that the rise of the flow stagnation temperature and the corresponding evaporation of the wall material cause significant wall cooling that leads to an increase in the near-wall density of the binary mixture. Such transformation of the boundary layer profiles leads to a decrease of disturbances amplification rates. Boundary layer stabilization occurs with an increase of flow stagnation temperature. The results of boundary layer transition experiments performed in a hot-shot wind tunnel are reported.