Many kelp aquaculture farms consist of moored arrays of long horizontal lines that grow kelp near the water surface. Most kelp farms are deployed in the same direction of wave propagation. However, with numerous longlines of densely grown kelp, these farms may have the potential to attenuate waves if installed perpendicular to the direction of wave propagation. In this application, the kelp farm may serve as a form of nature-based coastal protection. To assess this potential, a set of 1:10 scale physical model experiments were conducted to measure the wave attenuation of a suspended kelp model. The model was scaled based on the morphological and mechanical properties of the cultivated Saccharina latissima (sugar kelp) from Saco Bay, Maine, USA. Experimental results demonstrated that suspended blades have asymmetric oscillatory motions with more bending in the opposite direction of wave propagation. Due to severe asymmetric blade motion in large waves, the suspended blade could roll over the attached line following the wave orbital motion. The results also showed that suspended kelp farms in the designed configuration with 20 longlines of 1-m-long blades and 100 blades/m have the potential attenuating wave energy by up to 33.7% under the experimental wave conditions. Based on the experimental data, empirical formulas were developed for the bulk drag coefficient ($C_{DB}$) and effective blade length ($l_e$) of suspended kelp canopies for wave attenuation. To predict wave attenuation under a wider range of conditions and to identify the key parameters affecting wave attenuation, a numerical model was developed that could resolve blade motion. The benefits of resolving blade motion were to improve the model accuracy and reduce the number of experiments needed for obtaining $C_{DB}$ or $l_e$, which is required in the conventional wave attenuation models based on the rigid blade assumption. The results indicate that (i) the wave energy dissipation ratio ($EDR$ defined as the ratio of the dissipated wave energy to the incident wave energy) of suspended kelp farms decreases with increased water depth, (ii) $EDR$ is not sensitive to wave height, (iii) $EDR$ first increases and then decreases with wavelength, and (iv) $EDR$ increases with blade size, kelp vertical position, plant density, and the number of longlines. Therefore, the technique to improve the wave attenuation capacity of suspended kelp farms for nature-based coastal defense is to install the kelp farms in shallower water, expand the farm size by adding more longlines, locate the kelp in a higher position of the water column, grow the kelp more densely, and choose the kelp species with more rigid, wider, and longer blades/biomass.

许多海带水产养殖场由长水平线系泊阵列组成，这些线在水面附近种植海带。大多数海带养殖场都部署在相同的波浪传播方向上。然而，由于有大量密集生长的海藻延绳索，如果垂直于波浪传播方向安装，这些养殖场可能有衰减波浪的潜力。在这个应用中，海带养殖场可以作为一种基于自然的海岸保护形式。为了评估这种潜力，进行了一组 1:10 比例的物理模型实验，以测量悬浮海带模型的波浪衰减。该模型是根据栽培糖精的形态和力学特性进行缩放的（糖海带）来自美国缅因州萨科湾。实验结果表明，悬浮叶片具有不对称的振荡运动，在波传播的相反方向上有更多的弯曲。由于大波浪中叶片的严重不对称运动，悬挂的叶片可能会跟随波浪轨道运动在附着线上滚动。结果还表明，在试验波浪条件下，采用 20 条 1 米长叶片延绳索和 100 叶片/米的设计配置的悬浮海带养殖场具有衰减高达 33.7% 的波浪能量的潜力。根据实验数据，推导出体积阻力系数的经验公式（$C_{D乙}$) 和有效叶片长度 (${升}_{\mathrm{电子}}$) 用于衰减波浪的悬浮海带檐篷。为了在更广泛的条件下预测波浪衰减并确定影响波浪衰减的关键参数，开发了一个可以解决叶片运动的数值模型。解析叶片运动的好处是提高模型精度并减少获得所需的实验次数$C_{D乙}$ 或者 ${升}_{\mathrm{电子}}$，这是基于刚性叶片假设的传统波浪衰减模型所必需的。结果表明 (i) 波浪能耗散比 ($乙D\mathrm{电阻}$ 定义为悬浮海带养殖场的耗散波能与入射波能之比）随着水深的增加而降低，（ii） $乙D\mathrm{电阻}$ 对波高不敏感，(iii) $乙D\mathrm{电阻}$ 随波长先增大后减小，(iv) $乙D\mathrm{电阻}$随叶片尺寸、海带垂直位置、植物密度和延绳钓数量而增加。因此，提高悬空海带自然海防防浪能力的技术是将海带养殖场设置在较浅的水域，通过增加延绳线来扩大养殖场规模，将海带置于水体的较高位置。 ，将海带种植得更密，并选择具有更刚性、更宽和更长叶片/生物质的海带种类。