Contact Angle Adjustment in Equation of States Based Pseudo-Potential Model

TL;DR

This paper proposes a new geometry-based contact angle adjustment method for pseudo-potential lattice Boltzmann models, significantly improving stability at high density ratios and decoupling contact angle from surface tension effects.

Contribution

A novel contact angle adjustment technique based on geometry analysis that enhances model stability and accuracy for multiphase simulations with large density ratios.

Findings

Enhanced stability at density ratios over 1000

Decoupling of contact angle from surface tension

Improved accuracy of contact angle control

Abstract

Single component pseudo-potential lattice Boltzmann model has been widely applied in multiphase simulation due to its simplicity and stability. In many research, it has been claimed that this model can be stable for density ratios larger than 1000, however, the application of the model is still limited to small density ratios when the contact angle is considered. The reason is that the original contact angle adjustment method influences the stability of the model. Moreover, simulation results in present work show that, by applying the contact angle adjustment method, the density distribution near the wall is artificially changed, and the contact angle is dependent on the surface tension. Hence, it is very inconvenient to apply this method with a fixed contact angle, and the accuracy of the model cannot be guaranteed. To solve these problems, a contact angle adjustment method based on the geometry analysis is proposed and numerically compared with the original method. Simulation results show that, with the new contact angle adjustment method, the stability of the model is highly improved when the density ratio is relatively large, and it is independent of the surface tension.