Session: 09-01-06 Wind Energy: Aero-hydrodynamics 6

Paper Number: 129881

129881 - Model Test of a Semi-Submersible Floating Wind Turbine: Hydrodynamic Motions and Internal Loads 

A semi-submersible floating wind turbine (FWT) similar to OO-STAR in geometry was developed by the authors. This study is dedicated to experimentally fathoming its dynamic performance of motions and internal loads under wind and wave loads. Model tests were conducted in the ocean basin at Tsinghua Shenzhen International Graduate School. First, a physical model with a scale ratio of 1/28 was designed and fabricated, comprising an aluminum floating model, steel ballast, a small wind turbine, and a spread mooring system. A 6-axis force sensor is purposely placed at the root of central column for measuring the cross-sectional loads between the column and the floating foundation. Second, a series of model tests, including free-decay tests, RAO tests, wind-only tests, wave-only tests, and wind-wave tests, were carried out to investigate the intrinsic dynamic performance of the floating system. The test results not only demonstrated the effectiveness and reliability of such an experimental method of measuring the internal loads, but also revealed important dynamic characteristics of this floating wind turbine. Under wave loads, the platform exhibits low-frequency motion responses in pitch, heave, and surge, primarily concentrated at the 1^st-mode eigen-frequencies. In the tower top motions, in addition to the low-frequency response, there is a noticeable high-frequency response induced by the natural vibrations of the tower. Moreover, there are both low-frequency and high-frequency responses in the cross-sectional loads, including shear force and bending moment. However, the contribution of the high-frequency component is relatively small. In moderate sea states, the non-Gaussian effects due to frequency-sum and frequency-difference are not significant for shear force and bending moment in the tests.

Presenting Author: Yucong Jiang Tsinghua Shenzhen International Graduate School

Presenting Author Biography: Yucong Jiang is a Ph.D student in civil engineering at Tsinghua University Shenzhen International Graduate School (Tsinghua SIGS). He graduated from school of civil engineering Tsinghua University in 2021. Following his supervisor, Zheng Xiangyuan, Yucong Jiang's research firelds include offshore wind turbine and structrual dynamics.

Authors:

Yucong Jiang Tsinghua Shenzhen International Graduate School
Xiang Yuan Zheng Tsinghua Shenzhen International Graduate School
Shuaishuai Wang NTNU
Mengyang Zhao Tsinghua Shenzhen International Graduate School
Sheng Zhang Tsinghua Shenzhen International Graduate School
Torgeir Moan NTNU
Zhen Gao Shanghai Jiao Tong University
Wei Li POWERCHINA HUADONG ENGINEERING CORPORATION LIMITED