Computational study of an unsteady heat transfer problem related to high power lasers

Abstract

Unsteady heat transfer problems related to a closed cycle, pulsed, high power laser are characterized by sudden variations of fluid bulk temperature. An idealized model to represent these problems is the incompressible flow past a flat plate subjected to a step change in the fluid bulk temperature. The response of the wall heat transfer and the thermal boundary layer thickness to this step change in temperature are, therefore, calculated in this paper. The thermal boundary layer equation is cast in a finite difference form. This equation is solved by an explicit predictor-corrector method using a filtering parameter. The accuracy of the method is verified by comparison with the steady-state solutions at large times and was found to be excellent. Existence of similarity variables proposed in an earlier work using the integral method has been verified successfully.