Fluid-Structure Coupled High Mach Number Droplet Impacts with Immersed Boundary Method and Peridynamics

This paper presents a coupled computational framework that integrates an immersed boundary method (IBM)-based computational fluid dynamics (CFD) solver with a non-ordinary state-based peridynamics structural solver to investigate high-speed droplet impingement on deformable metallic targets. Both the fluid and structural dynamics solvers employ a fully axisymmetric formulation. The fluid domain is modeled using a sharp-interface, multi-phase formulation to solve the Allaire five-equation model which has been shown to capture the dominant flow phenomena relevant for single droplet impingement and damage predictions, albeit some effects such as phase change and dispersed phase behavior is not accounted for. The structural response accounts for strain-rate dependent elastic-plastic behavior within the peridynamics framework. Computed crater depths are validated against experimental data in the supersonic regime, and the study is extended to hypersonic conditions up to Mach 7. The current results highlight the importance of fluid–structure coupling, particularly in the hypersonic regime, where rapid structural deformation significantly influences the nonlinear, multi-physics nature of the impingement process.