Experimental generation of non-uniform surface temperature distributions in high-speed flow

Abstract This study presents prediction and experimental measurement of non-uniform surface temperature distributions on a flat plate test article for a flow control method. The test article features strips of materials (copper and MACOR) with dissimilar thermal properties interacting with a developing boundary layer to establish a passively controlled, non-uniform temperature profile. Experiments with a pre-heated model are conducted within the Imperial College supersonic wind tunnel at Mach 2.75. Infrared thermography is used for surface temperature measurements. Results from the experiments confirm the passive surface temperature control, demonstrating temperature variations between the strips. Furthermore, the physics-informed thermal model, with boundary conditions derived from actual wind tunnel conditions, predicts non-uniform surface temperature distributions that quantitatively align with the experimental results. Higher temperature differences between the strips of dissimilar materials can be achieved by increasing the difference between the recovery temperature and the initial temperature. These results validate the proposed actuation method’s ability to generate significant spanwise surface temperature variations. This validation of the actuation method serves as a prerequisite for future experimental campaigns, which will focus on measuring the induced velocity streaks and assessing their efficacy for boundary layer transition delay in hypersonic environments.