Ludwieg-Tube Experiments on the Effects of Laminar-Turbulent Transition on the SWBLI at Mach 6

Abstract

This report presents results of experimental investigations on the nominally 2-D impinging shock-wave interaction, induced by a 4 degree shock generator, with the transitional boundary layer developing on a flat plate at various unit Reynolds numbers and Mach 6 flow conditions. This investigations were conducted as the part of the ESA-project "Laminar to Turbulent Transition in Hypersonic Flows" to characterize the transition- and intermittency-detection techniques. Novel types of gages for high-frequency time-resolved heat flux (ALTP-gages) and pressure (PCBgages) measurements as well as the conventional thin-film and thermocouple heat-flux sensors were tested for this purpose and checked for plausibility by comparison with results of the quantitative infrared-thermography and high-speed shadowgraphy well-established for transition detection in quasi-steady flows. The advantages and limitations of each sensor type are discussed here.