Numerical predictions of the performance in flight of an air-breathing hypersonic vehicle: HyShot II

The uncertainties inherent to the operating conditions of the Hyshot II scramjet flight test are assessed. In particular, the variability of the pressure prediction in the combustor due to uncertain free stream conditions is investigated using a probabilistic methodology based on stochastic collocation. The uncertainties in Mach number, angle of attack and flight altitude are inferred from pressure measurements in the unfueled combustor using a Bayesian inversion approach. The forward computation relies on a reduced order model that represents the combustion processes in the scramjet combustor. A ground based experimental data set obtained from 1-to-1 model of the HyShot II vehicle with well defined operating conditions is used to validate the non-reacting solver and to calibrate the heat release model for the reacting combustor. The model prediction agrees well with the experimentally acquired flight data. On the other hand, our estimated flight free stream conditions differ from previously published results.