Crossflow On A Sharp 7 Degree Cone At Mach 5 At A 6 Degree Angle Of Attack

Abstract

Experiments were performed on a 7 degree sharp cone at 6 degree angle of attack in the University of Arizona Mach 5 Ludwieg Tube (LT5) aimed at exploring the breakdown of crossflow vortices. A Torlon sharp tip with discrete roughness elements (DREs) was manufactured and utilized to excite stationary waves associated with the crossflow instability while attenuating traveling waves. The campaign was administered to establish a foundation for crossflow research at the University of Arizona, and to observe the crossflow secondary instabilities that lead to breakdown at a hypersonic Mach number of 5. Transducers onboard the cone and infrared (IR) thermography were the tools used to record findings. Black matte 3M Wrap Film Series 2080 was applied to the cone's main frustum to facilitate IR measurements, which were recorded with a FLIR X8501sc middle wavelength infrared (MWIR) camera. Measurements by the IR camera were calibrated using constants converting radiance captured by the camera to temperature. These temperatures are then converted to heat flux. PCB 132B38 and Kulite XCE-062-20A transducers were used to record fluctuating pressures which were then converted to the frequency domain using the fast Fourier transform, and then the power spectral density (PSD) is calculated using Welch's method. Eleven PCBs were installed along with two Kulites. Two clusters of 4 PCBs and 1 Kulite were employed to measure traveling waves. The PSD of the PCBs showed peaks of possible secondary-instabilities and the second mode.