Pattern Formation in Liquid-Vapor Systems under Periodic Potential and Shear

TL;DR

This study investigates how shear flow affects pattern formation in a liquid-vapor system under a periodic potential, revealing phase stability changes and interface wave emergence at different shear rates.

Contribution

It introduces a lattice Boltzmann model for liquid-vapor systems with shear and periodic potential, analyzing phase stability and pattern transitions.

Findings

Striped phase remains stable at low shear rates.

High shear induces interface waves and phase destabilization.

Velocity patterns correlate with phase changes.

Abstract

In this paper the phase behavior and pattern formation in a sheared non-ideal fluid under a periodic potential is studied. An isothermal two-dimensional formulation of a lattice Boltzmann scheme for a liquid-vapor system with the van der Waals equation of state is presented and validated. Shear is applied by moving walls and the periodic potential will vary along the flow direction. A region of the parameter space, where in absence of flow a striped phase with oscillating density is stable, will be considered. At low shear rates the periodic patterns are preserved and slightly distorted by the flow. At high shear rates the striped phase looses its stability and a new phase with interface waves between the liquid and vapor regions will appear. Velocity field patterns will be also shown.