Transition Onset Prediction for High-Speed Flow

An approach that treats nonturbulent e uctuations in a turbulencelike manner and determines onset and extent of transition as part of a e ow calculation isused to study transition athigh Mach numbers. Threesetsof previously obtained experimental data involving straight and e ared cones at zero angle of attack are used to calibrate and validate the model. Two sets, at Mach numbers 3.5 and 6, were carried out in quiet tunnels, and the third set was carried out at a Mach number of 8 in a conventional tunnel. The results suggest that the second mode is not the only mode responsible for transition at high Mach numbers. In general, fair to good agreement with measured recovery factors, adiabatic wall temperatures, and heat-transfer rates is indicated.