Sensitivity Analysis of DSMC Parameters for Ionizing Hypersonic Flows

This work investigates the sensitivity of direct simulation Monte Carlo (DSMC) input parameters for a high temperature hypersonic flow scenario. The DSMC model simulates a rarefied hypersonic shock tube experiment with air. A previous model has been improved to include 11-species air with charged species collisions and reactions in order to model high temperature interactions appropriately. The DSMC code is ultimately to be linked with the HPC-Rad radiative transport code and results are to be compared with the NASA Electric Arc Shock Tube (EAST) data for a peak radiative heating lunar return scenario. A global Monte Carlo sensitivity analysis is conducted on this scenario to investigate which reaction rates have the greatest effect on the simulation results. The sensitivity of each reaction rate was measured by calculating the square of the Pearson correlation coefficient and the mutual information for a certain quantity of interest (QoI). The most sensitive parameters are identified in preparation for future Markov Chain Monte Carlo calibrations with the EAST data.