Wave interactions with multi-float structures: SPH model, experimental validation, and parametric study

Abstract

This paper proposes a new type of multi-float structures which comprise several serially arranged box-type modules. Adjacent modules are connected at the top corners using hinges, while rubber bumpers are placed at the bottom corners to absorb the collision energy. The whole structure is anchored to the seabed with mooring lines. A Smoothed Particle Hydrodynamics (SPH) model is established to study the wave interactions with such multi-float structures. In the SPH model, the Navier-Stokes equations are solved for the wave motion and the multi-degree-of-freedom motion of the structure is tracked by applying the Newton's second law to rigid bodies. A light spring model is used to evaluate the mooring forces, while the collision forces between adjacent modules are calculated according to the force-compression relation of the rubber bumpers. Besides, a continuity restriction on the linear acceleration is applied to the hinge connectors between adjacent modules. To validate the proposed SPH model, a laboratory experiment is conducted regarding the hydrodynamic performance of a three-float structure. Then, the SPH model is applied to a multi-float design scenario, from which useful findings have been obtained for engineering practice.