Boundary layer separation by a step in surface temperature

Abstract

Abstract—The free-interaction influence of thermal expansion process in the boundary layer gas flow is analysed in this paper, using the formalism of the Triple-Deck theory. The physical model considered herein is the forced convection of a gas flowing over a flat plate subject to a step change in the surface temperature, taking place at a certain distance from the leading edge. There is a fundamental parameter 7"w, defined as the ratio of the wall temperature to the free stream temperature. For values of Tw close to one, the governing equations can be linearized and solved with the aid of the Fourier transform method. However, for values of this parameter not close to one, a numerical treatment is required to solve the governing equations. Using finite-difference methods, the numerical results for the pressure, skin friction, thickness displacement and Nusselt number are presented for different values of T„. Finally, for a critical value of this temperature ratio, the boundary layer separates.