An improvement of rigid bodies contact for particle-based non-smooth walls modeling

Problems of fluid–structure interaction with free-surface flow and multiple bodies are highly nonlinear phenomena, which is challenging for computational modeling and simulation. Particle-based methods have been proven to provide a substantial potential for simulation of free-surface fluid flows and their interactions with multiple solids that are often encountered in fluvial and coastal mechanics fields, due to their Lagrangian tracking scheme and meshless nature. When contact between solids occurs, a numerical modeling to detect it and prevent penetration between bodies is required to avoid numerical inconsistencies. The objective of this work is to propose a solid–solid contact model that relays on contact mechanics theories and, by an effective way to determine the normal direction of contact as well as the distance between bodies faces, eliminates the numerical instabilities induced by non-smooth modeling of bodies surfaces in the particle-based methods. The model adopts a penalty-based method that uses a nonlinear spring and dashpot concept, and thus reproducing the macroscopic properties of the multiple bodies interactions. To avoid very small time step for all the domain, a dynamic sub-cycling algorithm for rigid bodies contact is adopted. First, the present fluid solver, based on the moving particle semi-implicit method, is validated by hydrodynamic and fluid–structure interaction problems. Then, analytical and numerical results are compared, demonstrating the improvements achieved by the proposed model. Finally, the present model is validated via 3D dam breaking events, in which rigid bodies interact with each other or with fixed walls.