An improved Riemann SPH-Hamiltonian SPH coupled solver for hydroelastic fluid-structure interactions

The paper presents a novel Lagrangian meshfree computational solver for simulation of hydroelastic fluid-elastic structure interaction (FSI) problems. An explicit Smoothed Particle Hydrodynamics (SPH) method, referred to as Riemann SPH, is adopted as the fluid model, and a SPH method within the Hamiltonian framework, namely Hamiltonian SPH (HSPH), is considered as the structure model. A two-way coupling between fluid and structure models is performed in a consistent manner, resulting in a coupled RSPH-HSPH hydroelastic FSI solver. For enhancement of accuracy and robustness of the proposed FSI solver, four refined schemes are incorporated for the fluid and structure models. These four refined schemes include (i) a novel dissipation limiter in the fluid's continuity equation for enforcing the volume conservation, (ii) a refined reconstruction of the quantities in Riemann SPH in the presence of a potential field, (iii) a modified velocity-divergence error mitigation term in the fluid's momentum equation for enhanced satisfaction of the incompressibility condition, and (iv) a Riemann diffusion term in the structural momentum equation for enhanced stability and robustness. Validations of the proposed FSI solver are carried out through a series of fluid, structure and FSI benchmark tests.