Numerical study of bubble collapse near a deformable wall using a partitioned coupling and a penalization method

Abstract

A numerical approach is developed for the simulation of fluid-structure interaction (FSI) problems and is applied to bubble collapse near a deformable wall, the phenomenon responsible for cavitation erosion. The present method is based on a partitioned coupling: The fluid flow is resolved in an in-house finite volume solver and structure dynamics are computed in FEniCS, an open-source finite element solver. Data communication between the two solvers and the space-time coupling of their respective solutions are handled by the coupling library preCICE. The novelty of the present strategy lies in the use of a penalization method to represent the solid body within the fluid solver, allowing the use of a fixed Cartesian grid for increased accuracy and reduced computational cost, as no remeshing is required for moving boundaries. Bubble collapse generates high-intensity shock waves that impact the surrounding wall, resulting in high equivalent stress in the material. When it exceeds the material yield strength, a cavitation pit forms. One-way and two-way coupling simulations are compared in order to demonstrate the need to consider strong coupling for this type of FSI problem. The influence of the initial bubble-wall distance on the resulting material damage is investigated.