(172e) Dynamics of Particle Cratering Using High Speed Gas Jets

Future space exploration necessitates improved gas-solid and solid-solid interaction models. Impinging rocket plumes from spacecraft interact with the lunar or Martian surfaces and release a high velocity particle spray that is hazardous to surrounding surface structures and affects the stability of spacecraft landings.  Understanding and predicting the dynamics of this particle cratering and erosion can aid in mitigating these hazards.  Ground-based experiments performed at the University of Florida provide detailed data on the particle cratering behavior as a function of time.  Data were obtained for the cratering of 2mm glass beads using a turbulent subsonic jet at various velocities.  It is shown that the particle cratering behavior can be successfully described using a combined CFD-DEM model developed at UNSW.  The model incorporates gas turbulence, gas-particle drag, and particle-particle contact forces.  In addition, the model enables the determination of the primary mechanism for particle cratering under the experimental conditions studied.  Particle erosion is confined to a thin shearing region along the crater boundary; hence, viscous erosion is the primary cratering mechanism.