An experimental study was performed to examine environmental disturbance effects on crossflow instability on a 2:1 elliptic cone, which is a canonical geometry with an extensive knowledge base. The present experiments were performed in the TAMU Mach 6 Quiet and ACE hypersonic wind tunnels. The wind tunnel data includes surface temperature/heat flux maps and surface pressure fluctuation spectra. The nominal freestream disturbances were less than 0.1% for Re/m = 6-10xl06 in the Mach 6 Quiet Tunnel, and 0.5% for Re/m < 2.8x10~6 and 1.5% for Re/m > 3.0xl0~6 in the ACE (conventional) Tunnel. The majority of data were acquired at zero incidence, with one case, in the M6QT, at 1-degree yaw. The transition process on the 2:1 elliptic cone was observed to vary both qualitatively and quantitatively across the freestream environmental changes. The high heat flux crossflow induced transitional fronts were altered in shape and occurred at significantly lower Reynolds numbers under noisy conditions. Modal content was observed in the crossflow region across the free stream disturbance range for frequencies less than 500 kHz, including stationary waves. However, ACE, modal growth occurred at significantly lower Reynolds numbers and appeared to be directly triggered by the freestream content change due to the wind tunnel nozzle boundary layers transitioning. Higher spectral content (500 - 1000 kHz) was observable under quiet conditions, with only modest corresponding content under noisy conditions. The near centerline axial instabilities were excited first under noisy conditions, where the opposite was observed under quiet conditions.
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