Linear stability analysis of Mach 10 nitrogen flow over 7-deg half-angle cones.

Linear stability theory (LST) analysis was performed on Mach 10 7-degree half-angle straight cones in nitrogen for comparison with experimental results obtained in the Arnold Engineering Development Complex (AEDC) Hypervelocity Wind Tunnel 9. The basic states considered were either generated by STABL at Sandia National Laboratories or with US3D at Baylor University. The LST analysis reproduced the trends of laminar-turbulent transition front moving forward with increasing unit Reynolds number for a sharp nose cone as well as the trend in transition front moving aft as nose bluntness is increased at a constant unit Reynolds number. The strengths of the instabilities were found to be consistent with those measured experimentally. It is hypothesized that the nose bluntness transition trends can be understood by analyzing the thermoacoustic impedance layer.