Design and modeling of an eco-friendly anchored fish aggregating device with artificial reef subjected to wave and current

Anchored fish aggregating devices (AFADs) and artificial reefs play a vital role in enhancing marine biomass and biodiversity for marine ecosystem restoration. Improving the coastal ecosystem remains a significant challenge worldwide. However, AFADs are highly vulnerable to damage under marine conditions, which can lead to significant marine pollution. An AFAD, in which an artificial reef is applied as the anchor, is designed to enhance the efficiency of marine ecosystem restoration. This system consists of a biodegradable raft, cotton rope, and concrete artificial reef. Numerical modeling is conducted to simulate the hydrodynamic performance of the AFAD based on an unsteady Reynolds-averaged Navier–Stokes approach with a realizable k–ε turbulence model. Wave forcing based on the Euler overlay method is applied for wave dissipation, followed by theoretical verification. The effects of wave parameters, relative raft length, rope length, raft diameter, and sinker weight on the motion response amplitude operators and relative rope tension are considered. The results show that the wave parameter has a significant effect on the hydrodynamic performance of the AFAD. With a relative raft diameter of 0.6, relative rope length of 2.6–2.8, and relative sinker weight of 0.8, the motion response amplitude operators and relative rope tension are minimized. The proposed AFAD can provide a stable three-dimensional zone to efficiently enhance the aggregation of marine species.