A linear electrical generator can be used on wave energy converter for converting the kinetic energy of a floating structure to the electricity. A wave farm consists of multiple wave energy converters which equipped in a sea area. In the present paper, a numerical model is proposed considering not only the interference effect in the multiple floating structures, but also the controlling force of each linear electrical generator. In particular, the copper losses in the electrical generator is taken into account, when the electrical power is computed. In a case study, the heaving motions and electrical powers of the multiple wave energy converters are estimated in the straight arrangement and triangle arrangement. In addition, the average electrical power is analyzed in different distances of the floating structures. The aim of this paper is to clear the relationship between the interference effect and electric powers from wave energy converters. This will be useful for deciding the arrangement of multiple wave energy converters.

The combination of aquaculture industry with floating offshore wind turbines has the potential to generate significant economic advantages for both industries. To investigate this potential, the present study focuses on analyzing the heave, and pitch dynamic responses of a Spar-type floating offshore wind turbine that incorporates an aquaculture feeding system. A series of water tank model tests, together with numerical calculations, were conducted using a 1/56 scale model of a 2 MW, displacement 3500 tons, floating Spar-type wind turbine. The feeding system was placed inside the Spar and slightly above the waterline by adjusting the configuration of the total weight. The weight of the feeding system in the experiments is 100 tons, capable of sustaining 300 tons of fish for an entire week, and the realistic applications have been expanded using the numerical calculation. For this reason, the present study serves a good case study for general understanding, because the integration of the feeding system inevitably raises the center of gravity of the structure and potentially affects its overall stability. The experiments revealed no discernible increase in the heave motion. Moreover, the pitch motion theoretically increased, but occasionally decreased in the experiments with the overall inclination angles being less than 1.2 degrees during the experiments. As a result, the present study supports the practice of integrating a Spar-type wind turbine with feeding systems. Future research should continue to comprehensively examine, both experimentally and numerically, the motion responses of the wind turbine and aquaculture facilities with varying configurations.

An improved constant panel method for more accurate evaluation of wave drift forces and moment is proposed. The boundary element method (BEM) of solving boundary integral equations is used to calculate velocity potentials of floating bodies. The equations are discretized by either the higher-order boundary element method or the constant panel method. Though calculating the velocity potential via the constant panel method is simple, the results are unable to accurately evaluate wave drift forces and moment. An improved constant panel method is introduced to address these issues. The improved constant panel method can, without difficulty, employ the near-field method to evaluate wave drift forces and moment, especially for multiple floating bodies. Results of the new evaluation method will be compared with other evaluation method. Additionally, hydrodynamic interaction between multiple floating bodies will be assessed.

This paper describes the relationship between an arrangement of Point Absorber Wave Energy Converter (PA-WEC) and power generation. In an array of PA-WECs, complex hydrodynamic interaction occurs. The interaction affects both increase and decrease of wave power density among PA-WECs. When aiming to maximize the generated electric power, it is necessary to appropriately select the control force of the generator in consideration of the positive effect of hydrodynamic interaction. This paper presents a numerical solution of the control force parameter for maximizing the generated electric power of the multi PA-WECs, taking into account the hydrodynamic interaction among PA-WECs in both diffraction and radiation problems. Then, numerical studies are carried based on the proposed method. From these results, the effects of the distance between PA-WECs and the number of PA-WECs in a linear arrangement on the generated electric power are discussed. In addition, the sensitivity of the arrangement of PA-WECs to the generated electric power is considered.

The integrated development of offshore wind power and marine aquaculture represents a promising approach to the sustainable utilization of ocean resources. The present study investigates the hydrodynamic response of an integrated wind energy-aquaculture structure. Physical water tank experiments were conducted on pontoon raft aquaculture facilities (PRAF) deployed around a wind farm monopile using the following three configurations: single-row PRAF (1) with and (2) without a monopile, and (3) three-row PRAF without a monopile. The interaction between the aquaculture structure and the wind farm monopile was examined, with a particular focus on the mooring line tensions and bridle line tensions under different wave conditions. The findings indicate that, among all configurations, both the maximum mooring line tension and bridle line tension decrease with increasing wave period and increase with increasing wave height. Utilizing the wind farm monopile foundation as an anchor, the mooring line tension was reduced significantly with the highest reduction of 66% in the single-row PRAF. The multi-row arrangement PRAF experienced lower mooring line tension in comparison to the single-row arrangement PRAF. However, for the bridle line tension, the upstream component enhanced while the downstream one weakened with a monopile, and they both decreased in multi-row arrangement. Finally, the numerical simulation results confirmed the dampening effects of the monopile on wave propagation. These findings provide insights into the hydrodynamic performance of integrated wind-aquaculture systems, offering scientific guidance for the optimal deployment of aquaculture structures within offshore wind farms.