Effects of the suspended kelp farm on wave propagation: A numerical study

As an environmentally friendly wave attenuation method, suspended kelp farms show great potential in protecting coastlines and marine engineering structures. To analyze the wave field characteristics around the suspended kelp farm, a three-dimensional numerical wave tank is established using the non-hydrostatic model. The kelp model is developed following the principles of the Euler-Bernoulli law. The effects of wave period, kelp blade density and length, and the distance from the fixed end of the blades to the water surface on the wave field around the suspended kelp farm are studied. The findings indicate that the suspended kelp farm can effectively attenuate wave height and form a trapezoidal area with lower wave heights downstream from it. The wave attenuation effect varies significantly with different wave periods, and when the period increases from 7 s to 10 s, the minimum transmission coefficient on the lee side decreases by 0.36. The increases in kelp density and the length of kelp blades both reduce the average wave height within the sheltered area and cause more noticeable wave reflection and diffraction. However, the size of the sheltered area slightly decreases, especially with higher kelp densities. This study is expected to provide effective guidance for the layout and site selection of suspended kelp farms.