タワーブイを用いた浮体式洋上風車の浅海係留方式に関する研究

• Published in: 日本船舶海洋工学会論文集 Vol. 36; pp. 41 - 51
• Main Authors: 鈴木, 英之, 髙岡, 繭子
• Format: Journal Article
• Language: Japanese
• Published: 公益社団法人 日本船舶海洋工学会 2022
• ISSN: 1880-3717; 1881-1760
• DOI: 10.2534/jjasnaoe.36.41

A technical challenge in deploying a floating offshore wind turbine in shallow water is dissolution of the poor performance of a catenary mooring system due to the decreased absorbable potential energy. It is common practice to improve mooring performance by using buoys and sinkers to enhance the potential energy absorbed by the mooring system. In this research, a tower-shaped buoy (tower-buoy) is proposed which is a buoy and a sinker integrated structure. In this design, a relatively large buoy and the sinker are connected by a column, and a chain subject to large tension by connecting the buoy and the sinker is removed. A mooring configuration is also proposed to maximize the effect of the tower-buoy.Regarding the proposed tower-buoy mooring, a static mooring performance analysis method was formulated, and static tension-displacement relation of the tower-buoy mooring is calculated and compared with the performance of conventional catenary mooring. It was shown that the tension of the mooring line of the tower-buoy can be significantly reduced compared with the catenary mooring. In addition, a wave tank experiment was carried out to investigate dynamic effect with a 1/35 scale model of a actual mooring deployed at a shallow water with depth of 50 m using φ 132 mm chain. The experimental results were compared with static analysis obtained by the formulated analysis, static and dynamic analysis by Orcaflex. The expected decrease in tension of mooring line is confirmed. Noticeable dynamic effects was also observed and cause was considered.