Fandi Oktasendra, Michael Rennick, Samuel J. Avis, Jack R. Panter, Halim Kusumaatmaja
We develop a diffuse solid method that is versatile and accurate for modeling wetting and multiphase flows in highly complex geometries. In this scheme, we harness N + 1 -component phase field models to investigate interface shapes and flow dynamics of N fluid components, and we optimize how to constrain the evolution of the component employed as the solid phase to conform to any pre-defined geometry. Implementations for phase field energy minimization and lattice Boltzmann method are presented. Our approach does not need special treatment for the fluid-solid wetting boundary condition, which makes it simple to implement. To demonstrate its broad applicability, we employ the diffuse solid method to explore wide-ranging examples, including droplet contact angle on a flat surface, particle adsorption on a fluid-fluid interface, critical pressure on micropillars and on Salvinia leaf structures, capillary rise against gravity, Lucas-Washburn's law for capillary filling, and droplet motion on a sinusoidally undulated surface. Our proposed approach can be beneficial to computationally study multiphase fluid interactions with textured solid surfaces that are ubiquitous in nature and engineering applications. © 2025 Author(s).
Department of Physics, Durham University, Durham, DH1 3LE, United Kingdom; Department of Physics, Universitas Negeri Padang, Padang, 25131, Indonesia; Institute for Multiscale Thermofluids, School of Engineering, University of Edinburgh, Edinburgh, EH9 3FD, United Kingdom; School of Engineering, Mathematics and Physics, University of East Anglia, Norwich, NR4 7TJ, United Kingdom
