On interplay of surface tension and inertial stabilization mechanisms in the interface dynamics with interfacial mass flux

TL;DR

This paper analyzes how surface tension and inertial effects influence interface stability with mass flux, revealing conditions for stability and instability, and providing benchmarks for experimental and simulation studies in high energy density plasmas.

Contribution

It introduces a comprehensive matrix method to analyze interface dynamics with mass flux, identifying new instability mechanisms influenced by acceleration, surface tension, and density ratio.

Findings

Instability occurs only under acceleration exceeding a threshold.

The instability features potential and vortical flow components in the bulk.

Strong accelerations lead to the fastest growth rates and highest surface tension stabilization.

Abstract

This work focuses on the interfacial dynamics with interfacial mass flux in the presence of acceleration and surface tension. We employ the general matrix method to find the fundamental solutions for the linearized boundary value problem conserving mass, momentum and energy. We find that the dynamics can be stable or unstable depending on the values of the acceleration, the surface tension and the density ratio. In the stable regime, the flow has the non-perturbed fields in the bulk, is shear-free at the interface, and has the constant interface velocity. The dynamics is unstable only when it is accelerated, and when the acceleration value exceeds a threshold combining contributions of the inertial stabilization mechanism and the surface tension. The properties of this instability unambiguously differentiate it from other fluid instabilities. Particularly, its velocity field has potential and vortical components in the bulk and is shear free at the interface. Its dynamics describes the standing wave with the growing amplitude, and has the growing interface velocity. For strong accelerations, this fluid instability of the conservative dynamics has the fastest growth-rate and the largest stabilizing surface tension value when compared to the classical Landau and Rayleigh-Taylor dynamics. We find the values of the initial perturbation wavelength at which the fluid instability can be stabilized and at which it has the fastest growth. We identify theory benchmarks for experiments and simulations in high energy density plasmas and its outcomes for application problems in nature and technology.