Analysis of Unstable Hydrofoil Energy-Capturing Motion Due to Energy Dissipation
Yudong Xie 1, 2  
Chen Chen 1, 2
Yong Wang 1, 2  
Penglei Ma 1, 2  
Jianwei Lu 1, 2  
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School of Mechanical Engineering, Shandong University, Shandong, China
Key Laboratory of High-Efficiency and Clean Mechanical Manufacture, Ministry of Education, Shandong, China
Yudong Xie   

School of Mechanical Engineering, Shandong University, 17923 Jingshi Road, School of Mechanical Engineering, Shandong University, 250061 Jinan, China
Online publish date: 2018-04-27
Publish date: 2018-05-30
Submission date: 2017-09-01
Final revision date: 2017-10-21
Acceptance date: 2017-10-22
Pol. J. Environ. Stud. 2018;27(5):2315–2324
As energy crises and environmental pollution become increasingly prominent, people are beginning to explore the ocean to exploit its renewable energy. Based on hydrodynamic principles, an analytical model for unstable hydrofoil motion has been developed. The software ANSYS Fluent was employed to perform a simulation of hydrofoil motion, and the effect of hydrofoil motion on the surrounding flow field was analyzed. The hydrodynamic characteristics and energy-capturing efficiency of the hydrofoil were obtained, and the influence of complex flows on hydrofoil hydrodynamics was elucidated. The energy dissipation mechanism during hydrofoil motion was characterized. The results indicate that the vortex generation and shedding inevitably dissipates part of the tidal energy captured by the hydrofoil, which leads to abrupt changes in hydrofoil hydrodynamics and reduces energy-capturing efficiency. When the frequency of the abrupt hydrodynamics change matches the hydrofoil natural frequency, it may result in hydrofoil resonance and damage. Also, it is observed that larger pitch amplitude leads to larger optimalreduced frequency corresponding to the peak power cycle-averaged coefficient. The results also provide a theoretical guide on how to improve hydrofoil energy-capturing efficiency of the power generation system with control valves and extend hydrofoil life.