Measurement of heat-transfer coefficients in shock wave-turbulent boundary layer interaction regions with a multi-layered thin film heat transfer gauge

A new type of thin film heat transfer gauge is applied to the measurement of heat-transfer coefficients in the interaction regions of incident shock waves and fully developed turbulent boundary layers. It has been developed to measure heat flux with high spatial resolution and fast response for wind tunnels with long flow duration. To measure the heat-transfer coefficients in the interaction region in detail, experiments were performed under the conditions of Mach number = 4, total pressure = 1.2 MPa, TW/T0 approximately in the range from 0.59 to 0.65, Reynolds number = 1.3 to 1.5 x 10 to the 7th, and incident shock angles from 17.8 deg to 22.8 deg. The results show that the heat transfer coefficient changes complicatedly in the interaction region. At the beginning of the interaction region, the heat-transfer coefficient decreases at first, reaches its minimum value at the point where the pressure begins to increase, and then increases sharply. When the boundary layer begins to separate, even a small separation bubble causes significant changes in the heat-transfer coefficient, while the pressure does not show any change which suggests that the boundary layer begins to separate.