INFLUENCE OF VIBRATIONAL EXCITATION OF THE GAS ON THE POSITION OF THE LAMINAR–TURBULENT TRANSITION REGION ON A FLAT PLATE

The influence of thermal nonequilibrium on the laminar–turbulent transition is studied with the use of the -method for two widespread flow regimes in a supersonic boundary layer at the Mach number . The set of the actual frequencies of spatial disturbances is determined on the basis of the neutral curves for temporal disturbances. Families of the curves of -factors are calculated for selected frequencies. Then, based on the envelopes of these curves, the transition Reynolds number for a given transition factor is determined. The calculations show that the transition region in the case with and vibrational excitation level below the dissociation limit is located 12–14% downstream as compared to the transition region in a perfect gas.