Surface effects on hydrodynamic evolution

TL;DR

This paper investigates how surface tension at the phase boundary influences the hydrodynamic expansion of a plasma, revealing that surface effects slow expansion and affect flow and anisotropy in heavy ion collision scenarios.

Contribution

It introduces a coupled hydrodynamics and order parameter model to analyze surface tension effects on plasma expansion in heavy ion collisions.

Findings

Surface tension slows down plasma expansion.

Surface effects influence radial flow development.

Surface tension impacts momentum anisotropy.

Abstract

We study the effect of surface tension of the phase boundary in the dynamics of an expanding fluid. A fluid at local thermal equilibrium, but has a slowly varying temperature profile, like the plasma formed in heavy ion collisions, will have rapidly varying order parameter field at the edge of the plasma where the temperature falls below the transition temperature. In the case where the free energy admits a first order transition, the gradient energy of this field will act as surface tension. We couple hydrodynamics and order parameter field evolutions to study the effect of this surface in the expansion of the plasma. We see that the surface slows down the expansion which reflects in the development of radial flow and momentum anisotropy.