Modelling Focused Breaking Wave Interactions With Pile-Net Aquaculture Structures (PNAS) Using REEF3D

Abstract For the first time, the hydrodynamics of and non-linear wave structure interactions between pile-net aquaculture structures (PNAS) and focused breaking waves are investigated using the open-source computational fluid dynamics (CFD) toolbox REEF3D. The inputting focused breaking wave is modelled by the transient wave packet method. A continuous direct forcing approach, along with an improved fluid density treatment, is integrated for the rigid body dynamics in the viscous fluid model. Additionally, the wave loads on the nets and their shielding effects are also modelled. Based on the validations of the numerical solver, the characteristics of impact forces on and focused breaking waves interacting with PNAS are discussed. The impact forces on piles and nets rise tremendously upon interacting with rolling breaker tongues, with peak values ranging from 156.9 to 209.3 kN in prototype terms. The peak force values on nets are merely 27.12% lower than piles, yet the nets experience a more pronounced rate of increase in force. From a localised perspective, the overturning breaker with significant wave particle velocities initially impacts the pile and net panel over a small contact area, where the local peak value can reach up to 8166.2 N on a prototype scale. This research has provided valuable insight into the designs or optimisation of PNAS in the future.