Influence of Vibrational Excitation of the Gas on the Position of the Laminar-Turbulent Transition Region on a Flat Plate
Yu. N. Grigoryev1, I. V. Ershov1,2
1Institute of Computational Technologies, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russia
2Novosibirsk State Agrarian University, Novosibirsk, 630039, Russia
Keywords: e-method, vibrational excitation, linear stability, laminar-turbulent transition, -factor integral curves
Abstract
The influence of thermal nonequilibrium on the laminar-turbulent transition is studied with the use of the eN -method for two widespread flow regimes in a supersonic boundary layer at the Mach number M = 4.5. 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 N-factors are calculated for selected frequencies. Then, based on the envelopes of these curves, the transition Reynolds number ReδT for a given transition factor NT is determined. The calculations show that the transition region in the case with NT = 8 and vibrational excitation level below the dissociation limit is located 12-14% downstream as compared to the transition region in a perfect gas.
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