Centered rarefaction wave with a liquid-gas phase transition in the approximation of "phase-flip" hydrodynamics

TL;DR

This paper compares two ideal-hydrodynamics models to study how metastable states and phase transitions affect fluid dynamics, revealing that rapid decay of metastable states can create rarefaction shocks.

Contribution

It introduces the phase-flip approximation to model metastable decay and demonstrates its effects on rarefaction wave solutions in fluid dynamics.

Findings

Rapid metastable decay causes rarefaction shock formation

Differences between equilibrium and phase-flip models are significant in flow dynamics

Implications for laser-heating experiments are discussed

Abstract

It is proposed to evaluate the effects of thermodynamic metastability on fluid dynamics by comparing two different ideal-hydrodynamics solutions --- one obtained with the fully equilibrium equation of state using the Maxwell construction, and the other in what we call the phase-flip approximation. The latter is based on the assumption of instantaneous decay of metastable states upon reaching the spinodal. The proposed method is applied to the classical problem of the centered rarefaction wave by expansion into vacuum, for which exact analytical solutions exist in both approximations. It is shown that the rapid decay of metastable states leads to the formation of a rarefaction shock in the expanding flow. Implications for the laser-heating experiments are discussed.