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 eN-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 ReδTis determined from the envelopes of families ofN-factor curves atNT= 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 laminarturbulent transition zone is displaced downstream by approximately 9% as compared to the case of a perfect gas.