High-Frequency Measurements of Acoustic and Entropy Disturbances in a Hypersonic Wind Tunnel

Abstract

With a combination of various pressure and heat flux sensors mounted on a range of probes the disturbance level of a Mach 6 Ludwieg tube is determined and characterized. Wide spectra of fluctuation values are obtained up to 1 Mhz. The measurements are carried out for different flow conditions and probe positions to identify the sensitivities of free stream disturbances effects on surface pressure and heat flux density fluctuation. Furthermore, modal analysis is presented where the measured flow quantities contribute to acoustic and entropy modes in the freestream. The cone surface data are being used to rebuild the freestream disturbance spectra by using high-fidelity numerical simulations. The results are compared with modal analysis using hot wire data.