Effects of pitching motion profile on energy harvesting performance of a semi-active flapping foil using immersed boundary method. (1st September 2018)

• Record Type: Journal Article
• Authors: Li, Weizhong; Wang, Wen-Quan; Yan, Yan; Tian, Fang-Bao
• Is Part Of: Ocean engineering. Volume 163(2018)
• Page Start: 94
• Page End: 106
• Publication Date: 2018-09-01
• Subjects: Projected immersed boundary method -- Semi-active flapping foil -- Energy harvesting performance -- Sine-like pitching motion -- Cosine-like pitching motion; Ocean engineering -- Periodicals; Ocean engineering; Periodicals; 620.4162
• DOI: 10.1016/j.oceaneng.2018.05.055
• Languages: English
• ISSNs: 0029-8018

Abstract

Abstract: Effects of pitching motion profile on energy harvesting performance of a semi-active flapping foil are numerically studied using immersed boundary method. Firstly, the numerical method is validated by considering a sinusoidal pitching semi-active flapping foil at Re = 1000 and a uniform flow over a stationary foil at Reynolds number Re = 500. Then, we consider a semi-active flapping foil with Reynolds number Re = 1000 and study the effect of sine-like and cosine-like pitching motion on the energy harvesting performance at reduced frequency f ∗ = 0.16. We study the pitching, with a gradual change from a sinusoid/cosinusoid to a square wave as β is increased from one. We found that increasing the value of β is ineffective to enhance energy harvesting efficiency for sine-like pitching motion, which is in agreement with the results of Deng et al. (2015) and Teng et al. (2016), however, for cosine-like pitching motion, the highest energy harvesting efficiency of 51.81% is recorded for pitching amplitude θ 0 = 60° and β = 2.0. Meanwhile, we observed that cosinusoidal pitching motion is more efficient for energy harvesting than sinusoidal pitching motion, and non-cosinusoidal pitching motion can enhance the harvesting efficiency compared to cosinusoidal pitching motion. In detail, we report the different performances of the sine-like and cosine-like pitching motion to study the mechanical mechanism of enhancing energy harvesting efficiency. Highlights: Semi-active flapping foil is simulated using immersed boundary method, easy to implement and enough accuracy. A semi-active flapping foil with sine-like and cosine-like pitching motion was studied and compared. For cosine-like pitching motion, the highest energy harvesting efficiency of 51.81% is recorded.