Numerical study on wave propagating characteristics through an offshore pile-net enclosure structure

Large-scale pile-net enclosures are increasingly utilized in marine engineering. However, simulating their interactions with waves remains a significant challenge. This study presents a numerical model that coupled porous media model and direct-forcing immersed boundary method to simulate the interaction between the pile-net enclosure structure and waves. The damping effect of the netting was simulated by porous media, while the pile was simulated using the direct-forcing immersed boundary method. The numerical model was verified based on experimental results obtained from corresponding physical model tests. Using the proposed numerical approach, this paper investigates the effects of wave period, net solidity, spacings of piles and wave incident angles on the hydrodynamic of the pile-net enclosure structure, including wave field and pile group coefficients. The results show that the pile-net enclosure structure demonstrates a damping effect on wave propagation, particularly for high-frequency waves. An increase in net solidity significantly impacts the wave forces on downstream piles. Additionally, the angle of incidence of the wave affects the orientation of the reflected wave crest line. When the piles are symmetrically positioned in pairs along the wave propagation direction, the wave height inside the structure decreases.