The Impact of Heave Motion on Gap Resonance in Floating Structures: A Numerical Investigation

The phenomenon of gap resonance has increasingly captured the attention of researchers due to its significant impact on offshore and coastal structures. Despite extensive studies, the effect of the heave motion of floating structures on gap resonance has lacked thorough investigation. This paper addresses this gap by using a two-dimensional numerical wave tank in OpenFOAM (version v1812) to compare both fixed-box and floating-box systems. Our findings reveal that the inclusion of the heave motions of structures shifts the resonance frequency to higher values (larger kh) and significantly reduces wave amplification compared with fixed-box systems. Furthermore, while gap resonance can induce extreme wave forces, its impact on the rear box in floating-box systems is minimal. These results underscore the necessity of considering the motion of floating structures in gap resonance studies to enhance the stability and design of offshore and coastal structures, a factor that has been insufficiently addressed in previous research.