TRANSIENT BEHAVIOUR OF THERMAL BOUNDARY LAYER DURING TRANSITION AFTER SUDDEN CHANGE OF INCIDENCE ANGLE

Heat transfer investigation was performed on a flat plate in a low subsonic wind tunnel for flow velocity U₀ = 15 and 20 m/s during the incidence angle change. The Stanton number variation in time along the plate is observed after the incidence angle is changed from i = −0.8 to 0°. While for the incidence angle i =−0.8° the flow is laminar, for the i =−0.6° the transition in boundary layer is occurred. To get the transitional flow the time about 30 minutes is needed after the angle change from i =−0.8 to −0.6°. This time is needed to achieve a new internal thermal balance in the plate. The temperature field in the flat plate is also registered according to the changes of the flow in the boundary layer.