Fluid-Structure Interaction in Cavitation Erosion

International audienceThis numerical work focuses on the collapse of a single air bubble close to a deformable wall generated by the impact of an incident high-pressure wave. A CFD code was fully coupled to a FEM solid code in order to compute the bubble collapse and the subsequent plastic deformation in the material. The CFD code FSI4CAV was developed from the numerical model of Johnsen et al. [1]. A mobile mesh capability was added in order to account for the displacement of the fluid-structure interface. This has been done through the implementation of an ALE (Arbitrary Lagrangian Eulerian) method. The solid response to the bubble collapse was computed with the FEM software CAST3M [2] assuming an elastic-plastic constitutive law for the material. The communication between the two codes is achieved through the MPI library. The paper presents a detailed analysis of the two-dimensional bubble collapse dynamics and the corresponding solid behaviour. The damping of the impact pressure with respect to a perfectly rigid wall was computed as well as the plastic deformation developed in the material. The comparison of the simulation results with a non-coupled approach where the pressure applied to the solid is computed from CFD simulations definitely shows the importance of including the fluid-structure interaction into the simulation of cavitation erosion