Higher-order Tuning of Interface Physics in Multiphase Lattice Boltzmann

TL;DR

This paper introduces a novel method to tune interface properties in multiphase lattice Boltzmann models, specifically targeting surface tension and Tolman length, to improve the accuracy of nucleation and cavitation simulations.

Contribution

It presents a new approach to leverage the forcing stencil in the Shan-Chen model for higher-order tuning of interface physics, including the Tolman length.

Findings

The method allows independent tuning of surface tension and Tolman length.

Simulations show nucleation rates depend on the Tolman length.

The approach enhances the fidelity of multiphase flow modeling.

Abstract

Tuning the interface properties of multiphase models is of paramount importance to the final goal of achieving a one-to-one matching with nucleation and cavitation experiments. The surface tension, at the leading order, and the Tolman length, at higher order, play a crucial role in the estimation of the free-energy barrier determining the experimentally observed nucleation rates. The lattice Boltzmann method allows for a computationally efficient modelling approach of multiphase flows, however, tuning results are concerned with the surface tension and neglect the Tolman length. We present a novel perspective that leverages all the degrees of freedom hidden in the forcing stencil of the Shan-Chen multiphase model. By means of the lattice pressure tensor we determine and tune the coefficients of higher-order derivative terms related to surface tension and Tolman length at constant interface width and density ratio. We test the method by means of both hydrostatic and dynamic simulations and demonstrate the dependence of homogeneous nucleation rates on the value of the Tolman length. This work provides a new tool that can be integrated with previously existing strategies thus marking a step forwards to a high-fidelity modelling of phase-changing fluid dynamics.