Estimate of the Onset of Laminar-Turbulent Transition on a Plate in Flight in the Mars Atmosphere

Abstract

Comparative calculations of the location of the onset of the laminar-turbulent transition zone are performed using the e^N-method for two points on the Mars “Pathfinder” entry trajectory. A three-component model of thermochemically nonequilibrium CO₂–CO–O mixture is used in the calculations. The set of spatial disturbance frequencies is found using neutral curves for the first unstable modes of temporary disturbances. The transition Reynolds number Re_δT is determined from the envelopes of families of N-factor curves at N_T = 8. In the hypersonic regime at M = 12.6, taking into account the developed thermochemical nonequilibrium leads to a significant decrease in the static temperature of gas in the lower part of the boundary layer. As a result, the onset of the laminar-turbulent transition zone is displaced downstream by approximately 9% as compared to the case of a perfect gas.