A unified diffuse interface method for the interaction of rigid bodies with elastoplastic solids and multi-phase mixtures

TL;DR

This paper introduces a versatile diffuse interface method for simulating interactions between rigid bodies, fluids, and elastoplastic solids in multi-physics Eulerian finite-volume simulations, enabling complex multi-material problems.

Contribution

A novel multi-physics-compatible immersed rigid body method using diffuse scalar fields and interface seeding, extendable to various applications including high-strain elastoplastic deformation.

Findings

Excellent agreement with experimental and numerical results

Method is straightforward, local, and parallelisable

Capable of handling complex 3D geometries with adaptive mesh refinement

Abstract

This work outlines a new multi-physics-compatible immersed rigid body method for Eulerian finite-volume simulations. To achieve this, rigid bodies are represented as a diffuse scalar field and an interface seeding method is employed to mediate the interface boundary conditions. The method is based on an existing multi-material diffuse interface method that is capable of handling an arbitrary mixture of fluids and elastoplastic solids. The underlying method is general and can be extended to a range of different applications including high-strain rate deformation in elastoplastic solids and reactive fluid mixtures. As such, the new method presented here is thoroughly tested through a variety of problems, including fluid-rigid body interaction, elastoplastic-rigid body interaction, and detonation-structure interaction. Comparison is drawn between both experimental work and previous numerical results, with excellent agreement in both cases. The new method is straightforward to implement, highly local, and parallelisable. This allows the method to be employed in three dimensions with multiple levels of adaptive mesh refinement using complex immersed geometries. The rigid body field can be static or dynamic, with the THINC interface reconstruction method being used to keep the interface sharp in the dynamic case.