Extraction of Wave Energy Using the Coupled Heaving Motion of a Circular Cylinder and Linear Electric Generator

*Department of Ocean System Engineering, Jeju National Universi ty, Jeju, Korea**Department of Civil Engineering, Kyongju University, Kyongju, KoreaKEY WORDS: Heave motion 수직운동, Linear electric generator 선형발전기, Power absorbtion 에너지 흡수, Matched eigenfunction expansion method 고유함수전개법, Double resonance 이중 공진, Circular cylinder 원기둥ABSTRACT: The feasibility of wave energy extraction from a heaving trunca ted cylinder and the corresponding response of the linear elect ric generator (LEG) composed of spring, magnet, and coil has been i nvestigated in the frame of three-dimensional linear potential theory. The heaving motion of a circular cylinder is calculated by means of the matched eigenfunction expansion method. Further, the analytical results are validated by numerical results using the ANSYS AQWA commercial code. By the action of a heaving circular cylinder, the magnet suspended by a spring can slide vertically inside the heaving cylinder. The mechanical po wer is extracted from the magnet motion relative to the coil/st ator which is attached to the cylinder. The coupled ODE of a heaving cylinder and LEG sys tem in waves is derived to obtain the magnet motion relative to a cylinder. To maximize the relative motion of the magnet, both the buoy draft and the LEG system parameters (spring stiffness, damping) should be selected properly for generating the double resonance considering the pe ak frequency of the target spectrum.교신저자 조일형: 제주시 제주대학로 66, 064-754-3482, cho0904@jejunu.ac.kr