Blast dynamics in a dissipative gas

Matthieu Barbier 1 Dario Villamaina 2 Emmanuel Trizac 3

Physical Review Letters, American Physical Society, 2015, 115, pp.214301

The blast caused by an intense explosion has been extensively studied in conservative fluids, where the Taylor-von Neumann-Sedov hydrodynamic solution is a prototypical example of self-similarity driven by conservation laws. In dissipative media however, energy conservation is violated, yet a distinctive self-similar solution appears. It hinges on the decoupling of random and coherent motion permitted by a broad class of dissipative mechanisms. This enforces a peculiar layered structure in the shock, for which we derive the full hydrodynamic solution, validated by a microscopic approach based on Molecular Dynamics simulations. We predict and evidence a succession of temporal regimes, as well as a long-time corrugation instability, also self-similar, which disrupts the blast boundary. These generic results may apply from astrophysical systems to granular gases, and invite further cross-fertilization between microscopic and hydrodynamic approaches of shockwaves.

  • 1. Department of Ecology and Evolutionary Biology [Princeton]
  • 2. LPTENS - Laboratoire de Physique Théorique de l'ENS
  • 3. LPTMS - Laboratoire de Physique Théorique et Modèles Statistiques