Heaving displacement amplification characteristics of a power buoy in shoaling water with insufficient draft

다국어 초록 (Multilingual Abstract)

The resonance power buoy is a convincing tool that can increase the extraction efficiency of wave energy.
The buoy needs a corresponding draft, to move in resonance with waves within the peak frequency band where wave energy is concentrated. However, it must still be clarified if the buoy acts as an effective displacement amplifier, when there is insufficient water depth. In this study, the vertical displacement of a circular cylinder-type buoy was calculated,with the spectrum data observed in a real shallow sea as the external wave force, and with the corresponding draft, according to the mode frequency of normal waves. Such numerical investigation result, without considering Power Take-Off (PTO) damping, confirmed that the area of the heave responses spectrum can be amplified by up to about tenfold,compared with the wave energy spectrum, if the draft corresponds to the peak frequency, even with insufficient water depth. Moreover, the amplification factor of the buoy varied, according to the seasonal changes in the wave spectra.

참고문헌 (Reference)

1 권혁민, "파력발전장치 설계를 위한후포 연안의 파랑 분석 및 스펙트럼 추정" 한국해안,해양공학회 25 (25): 147-153, 2013

2 권혁민, "공진형 전력부이의 상하변위증폭 효과에 관한 실험적 연구" 대한토목학회 33 (33): 585-594, 2013

3 Falnes J., "Wave-energy conversion through relative motions between two single-mode oscillating bodies" 121 : 32-38, 1999

4 Cho, I. H., "Wave energy converter by using relative heave motion between buoy and inner dynamic system" 2 (2): 297-314, 2012

5 French, M.J., "The systematic design of economic wave energy converters" ISOPE 106-109, 1995

6 Grilli, S. T., "Small buoys for energy harvesting : Experimental and numerical model studies" ISOPE 598-605, 2011

7 Budal, K., "A resonant point absorber of ocean wave power" 256 : 478-479, 1975

8 French, M. J., "A generalized view of resonant energy transfer" 21 (21): 299-300, 1979