Particle Flow Physics Modeling for Extreme Environments

The liberation of particles induced by rocket plume flow from spacecraft landing on unprepared regolith of the Moon, Mars, and other destinations poses high mission risks for robotic and human exploration activities. This process occurs in a combination of "extreme environments" that combine low gravity, little or no atmosphere, with rocket exhaust gas flow that is supersonic and partially rarefied, and unusual geological and mechanical properties of highly irregular soil regolith. CFDRC and the University of Florida have previously developed unique plume driven erosion simulation software for such environments by combining novel granular physics simulation modules developed by UF with the Unified Flow Solver (UFS) plume flow simulation software developed by CFDRC. Granular flow constitutive models, formulated through first-principle 3-D Discrete Element Method particle kinetics simulations, were implemented for efficient Eulerian gas-granular flow CFD modeling in the UFS simulation framework. Resultant simulations realistically capture the granular flow characteristics of particle erosion and cratering scenarios. The goal of this project is to dramatically advance the fidelity of these simulations towards simulating actual extra-terrestrial soil compositions with broad shape and size variations. This will be achieved through applying recent, novel particle kinetics modeling concepts to formulate granular flow physics models for both, realistic irregular particle shapes and realistically dispersed particle size distributions. The proposed technology development will result in unprecedented computer modeling capability for predicting liberation and flow of realistic granular material compositions in extreme extra-terrestrial environments.