(143b) Predicting Erosion Dynamics of Regolith During Lunar Landing Using the Discrete Element Method (DEM)

The supersonic plume of a landing rocket entrains lunar regolith, which is a layer of loose, heterogeneous, polydisperse solids covering the lunar surface. This entrainment is often problematic due to scouring and dust-impregnation of surrounding hardware, reduction in visibility for the crew, and spoofing of the landing sensors. Hence, it is extremely important to predict the erosion dynamics of regolith to both assess and reduce the problem. Previous predictions have been based largely on limited empirical data and oversimplifying assumptions. In the present work, the parameters affecting the erosion rate are investigated using the Discrete Element Method (DEM). The flow of exhaust rocket plume has been studied using CFD elsewhere and the results have been incorporated into this work. Also, a one-way coupling is incorporated such that the gas flow affects the particle flow but not vice versa. Forces on the particles due to the gas are modeled as drag and lift coefficients following the work of Loth et al. (AIAA Journal, 46(4), 2008) The results indicate that DEM simulations are capable of reproducing trends in the erosion rate that are known experimentally and in addition give valuable insight into the significance of inter-particle collisions on the erosion rate. The latter is particularly important since the role of such collisions on erosion rate was previously neglected.