Rapid Parametric Sensitivity Analysis for Plume-Surface Interaction Simulations

NASA modeling and simulation activities are mandated to provide uncertainty characterization, quantification (UQ), and propagation for all of their simulation tools and results. In the Phase I of this project, CFD Research addressed this need by implementing two approaches for sensitivity analysis into the Gas Granular Flow Solver, Loci/GGFS, used by NASA for prediction of Lunar and Martian Plume-Surface Interaction (PSI) effects such as dust lofting, obscuration, debris transport, and surface cratering. The first method, the intrusive methodology Forward Automatic Differentiation (FAD), enables run-time sensitivity analysis and propagation of the underlying sub-model uncertainties through a simulation in a minimal number of runs. The second method was the nonintrusive Sensitivity Quantification for Uncertainty Analysis Toolkit (SQUAT). Both approaches quantified sensitivities in a PSI validation problem. In Phase II, CFD Research will mature both methodologies. The efficiency and applicability of FAD will be improved for a broad class of problems in Loci/GGFS and other Loci solvers including Loci/CHEM, which is used for a variety of applications by NASA. SQUAT will be extended to work with all Loci-based solvers. Both uncertainty analysis methods can also be adapted for implementation or integration with other CFD solvers to enable critically needed UQ and sensitivity analysis for a wide range of NASA and non-NASA applications. At the end of this project, a full suite of UQ tools will be available to the analyst for sensitivity analysis, allowing identification of dominant sub-model contributors of uncertainty, guide improvements, and provide a rapid propagation of critical uncertainties to the simulation output metrics. nbsp;The resulting tools will be delivered to NASA for ready application to analysis of Lunar and Martian landers, including the Human Lander System, to aid in quantifying and propagating uncertainties in current simulations.