1 Comparison of Potential Flow and Viscous Fluid Models in Gap Resonance

This work presents numerical simulation results of wave motion in narrow gaps subjected to incident water waves using both potential theory flow model and viscous fluid model, including single narrow gap separated by twin bodies and double narrow gaps between three identical bodies. The numerical results of variation of wave height in the narrow gaps with incident wave frequencies are compared with available experimental data. The numerical results and comparisons indicated that both potential flow model and viscous fluid model are able to predict the resonant frequency. However, it was found that potential flow model significantly over-predict the wave height in narrow gaps at frequencies near the resonant frequency. It was revealed that the viscous effect/or energy dissipation plays an important role in limiting the wave height in narrow gaps at resonance. The mechanism of fluid forces on structures is also investigated based on the numerical simulations using the viscous fluid model. Key word