Plume Impingement on a Dusty Lunar Surface Available to Purchase

A loosely coupled continuum‐DSMC solver is used to simulate the interaction between the exhaust from a rocket engine with the lunar surface. This problem is of particular interest because the high velocity dust spray can damage nearby structures. The flow field is challenging to simulate because continuum assumptions are no longer valid in the far field, while in the near field DSMC becomes impractical because of the high collision rate. In the current work the high density core of the rocket plume is modeled with NASA’s continuum flow solver, DPLR [1]. Since the two solvers are loosely coupled, i.e. one‐way coupling from the DPLR to the DSMC regimes, the interface between the two solvers is placed in the supersonic region above the surface shock. At the lunar surface, a boundary layer develops and the shear stress causes dust grains to slide and eventually enter the flow field. Robert’s theory of dust entrainment [2,3] is used to predict how much dust is lofted into the flow field by the near surface flow conditions. In Robert’s original theory the interaction between entrained dust grains and the gas was neglected and the particles were assumed to follow ballistic trajectories. In our current model, the dust grains are coupled with the DSMC gas model. Both the dust trajectories and the flow fields are computed for various hovering altitudes and dust grain sizes. Comparisons are made to Robert’s original predictions and Apollo photogrammetry [4].