Effect of incoming gravity waves on the energy extraction efficiency of flapping wing hydroelectric generators

Abstract

The energy extraction performance of flapping wing hydroelectric generators is subject to the effects of the free surface and incoming gravity waves. The present work addresses this issue by conducting transient numerical simulations of a two-dimensional flapping wing system. The effects of the wave wing phase difference, encounter frequency, and wing submergence depth on the energy extraction performance are investigated. The results indicate that the phase difference is the primary factor affecting the energy extraction efficiency. The incoming gravity wave has the most positive effect on the energy extraction efficiency when it's in the range of 0°–90°. In addition, the energy extraction efficiency increases with the increase in the encounter frequency. Moreover, the periodicity is best when the oscillation frequency of the wing is equal to the encounter frequency. Finally, the influence of the submerged depth on the energy extraction efficiency is also discussed.