Resonance wave pumping with surface waves
In this paper, we present a novel extension of impedance (Liebau) wave pumping to a free-surface condition where resonance pumping could be used for hydraulic energy harvesting. Similar pumping behaviours are reported. Surface envelopes of the free surface are shown and outline two different dynamics: U-tube oscillator and wave/resonance pumping. The latter is particularly interesting, since, from an oscillatory motion, a unidirectional flow with small to moderate oscillations is generated. A linear theory is developed to evaluate pseudo-analytically the resonance frequencies of the pump using eigenfunction expansions, and a simplified model is proposed to understand the main pumping mechanism in this type of pump. It is found that the Stokes mass transport is driving the pump. The conversion of energy from paddle oscillation to mean flow is evaluated. Efficiency up to 22 % is reported.
© 2016 Cambridge University Press. Received 7 February 2016; revised 8 September 2016; accepted 27 October 2016; first published online 6 December 2016. The authors would like to acknowledge the Gordon and Betty Moore Foundation for their generous support. The authors would also like to thank C. Roh, J. Harris, M. Grivel, N. Martin and S. Boyaval for their help with the project and the editing of this manuscript.