Blast dynamics in a dissipative gas

TL;DR

This paper explores self-similar blast wave solutions in dissipative gases, revealing layered shock structures, temporal regimes, and instabilities, with validation from Molecular Dynamics simulations, extending classical blast theory to non-conservative media.

Contribution

It derives and validates a new self-similar solution for dissipative blast waves, highlighting layered structures and instabilities, bridging microscopic and hydrodynamic approaches.

Findings

Identification of layered shock structure in dissipative media

Prediction of a long-time corrugation instability

Validation through Molecular Dynamics simulations

Abstract

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.