Sensitivity Analysis and Uncertainty Quantification for a Set of Hypersonic Shock Interaction Flows

Abstract

Hypersonic gas flows around double cone and double wedge geometries tend to involve complex shock-shock and shock-boundary layer interactions, and are characterized by the formation of several flow structures which are highly sensitive to physical models and input parameter values utilized in flow simulation. This work is intended to clarify the influence of several modeling parameters and approximations on output quantities of interest by means of a more global and systemic approach than has previously been employed for these types of flows. A Monte Carlo approach for sensitivity analysis (SA) and uncertainty quantification (UQ) is integrated with a new direct simulation Monte Carlo (DSMC) gas flow simulation code, and a large number of DSMC simulations are performed for a representative hypersonic flow over a double cone. Simulation results are analyzed to determine the relative sensitivity of local and global output quantities to several input uncertainties, and probability distributions are computed for these output quantities. Aleatory and epistemic uncertainties are considered independently with different sampling techniques, and both uncertainty types are included in UQ and SA calculations. In addition to DSMC-based SA/UQ calculations, double cone calculations are presented for a NavierStokes computational fluid dynamics (CFD) code. DSMC and CFD simulation results are compared with other computational and/or experimental data to ensure simulation accuracy under nominal flow conditions, and UQ results are employed to help explain discrepancies with published data.