Constant entropy sampling and release waves of shock compressions

TL;DR

This paper introduces equilibrium methods for calculating isentropic processes during shock compression and release, comparing results with nonequilibrium simulations to understand deviations caused by viscosity and other effects.

Contribution

The paper develops new equilibrium techniques to model isentropic processes and compares these with nonequilibrium simulations for shocked liquids.

Findings

Equilibrium methods effectively compute isentropic release.

Viscosity and nonequilibrium effects cause deviations from ideal isentropic behavior.

Comparison shows non-ideal effects are significant in high-pressure releases.

Abstract

We present several equilibrium methods that allow to compute isentropic processes, either during the compression or the release of the material. These methods are applied to compute the isentropic release of a shocked monoatomic liquid at high pressure and temperature. Moreover, equilibrium results of isentropic release are compared to the direct nonequilibrium simulation of the same process. We show that due to the viscosity of the liquid but also to nonequilibrium effects, the release of the system is not strictly isentropic.