Abstract

Convective heat transfer problems occur in many technical application. Unsteady transition in the heated boundary layer is one of them. Heat transfer investigation of a flat plate in a low subsonic wind tunnel for flow velocity U_o = I5 and 20 m/s was performed. The changes in time of the Stanton number distribution along the plate were observed after the incidence angle had been changed from - 0.8 to 0^o. While for the incidence angle i = -0.8^o the flow in bouudary layer was laminar, for the angle -0.6^o the transition was observed, and for the angle -0.23^o the flow was turbulent. After the sudden change of angle the transient behaviour of the heat transfer between these three states were observed, e.g. for the change from -0.8 to -0.6^o from laminar to transitional, so after the time of about 30 min the transition was perfect. This time is needed to achieve a new internal thermal balance of the plate and transition in thermal boundary is established.