Comprehensive Uncertainty Analysis of Mars Entry Flows over Hypersonic Inflatable Atmospheric Decelerators

摘要

A comprehensive uncertainty analysis for high-fidelity flowfield simulations over a Hypersonic Inflatable Atmospheric Decelerator for Mars entry is presented for fully laminar and turbulent flows. The current study implements a sparse-collocation approach for efficient and accurate uncertainty quantification in the high-fidelity numerical modeling of hypersonic reentry flow simulations, which may contain large numbers of aleatory and epistemic uncertainties. The mixed uncertainty quantification results show that the computational cost can be reduced by at least 80% compared to the sample requirements for constructing a total order stochastic expansion. The aerodynamic heating (both convective and radiative) and wall pressure uncertainties are computed and shown to vary due to a small fraction of 65 flowfield and radiation modeling parameters considered. The main contributors to the convective heating uncertainty near the stagnation point are the CO_2-CO_2, CO_2-O, and CO-O binary collision interactions, freestream density, and freestream velocity for both boundary layer flows. In laminar flow, exothermic recombination reactions are more important at the shoulder. The radiative heating and 'wall pressure uncertainties were shown to have consistent contribution for both boundary layer flows. The main contributors to the radiative heating uncertainty were the CO_2 dissociation rate and CO_2-O exchange rate due to the strongly-emitting CO_2 ultraviolet band at peak stagnation-point heating. The freestream density variation dominates the uncertainty in the wall pressure.