Dynamic behaviors of a hinged multi-body floating aquaculture platform under regular waves

Abstract

This paper numerically studies the dynamic behaviors of a hinged multi-body floating aquaculture platform under regular waves. A coupled scheme that integrates the boundary element method (BEM) and the lumped-mass model is used to model the frames and the moorings/netting simultaneously. The effect of the hinge-joint rotational stiffness on the motion responses, mooring and hinge-joint forces at different wave steepnesses are examined. The results show that both the wave period and the hinge-joint rotational stiffness affect the pitch response of the multi-body aquaculture platform. However, the hinge-joint rotational stiffness has a predominant influence on the maximum pitch response. Unlike the pitch response, the stiffness has little effect on the heave response. Moreover, with the increase of stiffness, these two individual cages also show distinctive dynamic behaviors. The mooring force decreases with the stiffness and a 14.5% reduction has been obtained at the maximum stiffness. Under the same wave period, the y-direction rotation moment increases alongside the stiffness. When the wavelength is less than 0.9 times the structural span, the increased wave period decreases the y-direction rotation moment. In contrast, the stiffness rarely affects the z-direction hinge-joint force.