Collaborative Research: Shock interaction with a complex hydrodynamic medium

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PI: Vorobieff, Peter / Jacobs, GustaafProposal Number: 1603915 / 1603326When a gas moves at high speeds, a pressure shock is often formed. A comprehensive study that involves experiments and computations is proposed for the case when small particles are also present. Practical applications of the proposed work are found in a plethora of engineering technologies that involve mixing, such as supersonic and hypersonic combustion, and dust explosions (in coal mines and in grain or sugar silos). A better understanding of the basic physics of shock-driven mixing will lead to improved designs in the energy area, reducing use of natural resources and impact on the environment.It is proposed to study shock-driven instabilities in particle-laden flows, where large-scale density gradients are present in the gas phase simultaneously with presence of the particle phase, and the latter may account for a significant fraction of the volume-averaged density. The proposed effort aims to overcome the current disconnect between the studies of the purely hydrodynamic features of shock-driven media (Richtmyer-Meshkov instabilities (RMI), secondary instabilities, and transition to turbulence) and multiphase features of the same flows. By combining computational analysis, experiment and theoretical and model developments, a benchmark set will be developed to prepare for a detailed investigation of the relevant physics, not just in terms of gross flow behavior, but with focus on subtler mixing phenomena induced by baroclinic and particle-gas interaction mechanisms. Experiments will be conducted in the University of New Mexico shock tube, one of the most advanced research facilities of this type in the world. It has a design Mach number of 4 and a highly modular architecture allowing to study shock interaction with a wide variety of objects with minimal reconfiguration. Computations will be conducted with Eulerian-Lagrangian and Eulerian-Eulerian codes based on higher-order Weighted-Essentially-Non-Oscillatory (WENO) schemes that have been developed by the PI at SDSU. The codes will be validated for the interaction of shock and cloud of particles. Effects on flow morphology caused by non-uniformities in the seeding and particle size distribution will be determined. Three-dimensional computations of the complete system and experiment will provide insight into the fully non-linear flow development. The work will engage students from underrepresented groups, encouraging them to pursue long-term careers in STEM-related fields.