An experimental investigation of crater formation physics during plume-surface interactions using non-intrusive measurement techniques

Abstract

In this dissertation, a stereo-photogrammetry technique for obtaining non-intrusive, full-domain measurements of Plume-Surface Interaction (PSI) crater evolution was developed. Using this technique, crater formation was studied at multiple static nozzle heights above the surface, multiple nozzle mass flow rates, and at both Earth atmospheric and sub-atmospheric ambient pressure conditions. From the stereo-photogrammetry data, time-resolved 3-D reconstructions of the crater geometry were generated, and crater depth, radius, and volume evolutions were extracted.

Results show that the stereo-photogrammetry technique is able to accurately measure the crater formation process. Under Earth atmospheric ambient pressures, the crater depth was observed to grow logarithmically with time at high nozzle heights but more rapidly at low nozzle heights. Craters formed under Earth atmospheric ambient pressure had an axisymmetric parabolic geometry. Crater geometry changed significantly across ambient pressure conditions. Craters formed under Earth atmospheric pressure had an axisymmetric parabolic geometry while craters formed at some nozzle heights under sub-atmospheric pressures had a lobed geometry characterized by azimuthal depth variations. The data were used to investigate crater formation scaling laws and a new physics-informed scaling law for the crater depth evolution was proposed.