Coupling between an SPH-based fluid solver and mooring dynamics for floating offshore devices: DualSPHysics and MoorDynPlus

This paper presents a two-way coupling methodology between the robust Smoothed Particle Hydrodynamics (SPH)-based fluid solver DualSPHysics and the lumped-mass mooring dynamics solver MoorDynPlus. Such integration enables accurate and efficient simulation of the complex hydrodynamic interactions between floating structures and their mooring systems, and is well suited to address wave–structure interaction, including extreme wave conditions. Details of the mooring solver and the coupling framework formed by DualSPHysics-MoorDynPlus are presented, highlighting the proposed methodology implementation for efficient data exchange between the two solvers. The coupled model is rigorously validated against a comprehensive experimental dataset obtained from a dedicated research campaign conducted as part of the SURVIWEC project, which tested two 1:15 scale model devices – one equipped with taut moorings and the other with catenary moorings – subjected to a variety of wave conditions, including regular and focused wave trains. The presented results demonstrate that the DualSPHysics-MoorDynPlus model can accurately predict the dynamic response of the floating structures, including their motions and the associated mooring line tensions. It effectively captures non-linear hydrodynamic effects, which are crucial for assessing the survivability of offshore structures under extreme wave conditions. This work provides a valuable tool for the design and analysis of offshore renewable energy devices, as well as other marine structures operating in challenging ocean environments.