Experiments on the effect of laminar–turbulent transition on the SWBLI in H2K at Mach 6

This paper presents the results of the experiments performed in the hypersonic wind tunnel H2K in the framework of the ESA technology research project “laminar to turbulent transition in hypersonic flows”. The investigations include the free boundary-layer transition on a flat plate as well as the influence of a shock wave–boundary layer interaction on the transition. The shock is created by a wedge with a small angle of attack resulting in a moderate shock intensity. The experiments were performed at Mach 6.0, at three different unit Reynolds numbers and with a translational displacement of the shock generator. Besides the optical methods—Schlieren photography and infrared thermography—several intrusive sensors were used. High-speed measurements were carried out using PCB and atomic layer thermo pile sensors. Kulite sensors were used for low- and mid-speed pressure measurements. The data analysis includes the comparison of the absolute values, the frequency spectra and wavelets and their distributions in time and space