Explosion-driven Rayleigh-Taylor instability in gas-particle mixtures

The structure and growth of an explosion-driven Rayleigh-Taylor instability in gas-particle mixtures is investigated using two-dimensional numerical simulations. Particle concentration and diameter are varied and the growth of the ensuing mixing layer and its dependence on these parameters is investigated. The hydrodynamic structures are subdued and lose their coherence with increase in solid particle concentrations. When the solid particle concentration is fixed but particle diameter varied, a non-monotic behavior is observed. It is found that an intermediate particle size results in the widest mixing zone and degree of mixing. This is due to the differences in the spatial accumulation of the particles as they disperse. Small particles accumulate in the bubbles and around the spikes of the Rayleigh-Taylor structures; intermediate-sized particles in the tips of the spikes and as roots into the driver fluid; large particles accumulate primarily in the spikes and as thin, elongated roots into the driver fluid. Such differences are attributed to the response time or Stokes number of the particles. Finally, future directions for extending the current research are summarized. (C) 2014 AIP Publishing LLC.