SPH modelling of mechanics of modular raft floating photovoltaic system in waves

The growing deployment of floating photovoltaic (FPV) systems in offshore environments requires a clear understanding of their hydrodynamic behaviour under waves. This study presents a numerical investigation of a modular raft FPV system subjected to regular waves using the smoothed particle hydrodynamics (SPH) method. The floating modules are interconnected by hinges modelled as linear zero-length springs and moored by linear massless springs that only generate tensions when taut. The SPH model is validated against two laboratory experiments, showing good agreement in wave elevations, structural motions, hinge forces, and mooring forces. A parametric study is then carried out to examine the effects of wave period, wave height, and mooring angle on the hydrodynamic response of the FPV system. Results show that under shorter waves, the upwave modules experience larger motions, whereas under longer waves the motion response becomes more uniform across all modules. Heave displacement and roll angle increase approximately linearly with wave height, but hinge and mooring forces grow at a superlinear rate. Increasing the mooring angle generally reduces hinge and mooring forces, but amplifies the roll motion of the moored modules. These findings provide practical guidance for the design of modular raft FPV systems.