Hydrodynamics and load shedding behavior of a variable-geometry oscillating surge wave energy converter (OSWEC)

In order to improve their long-term viability, wave energy converters (WECs) need be able shed loads when a threshold condition is exceeded. As shown by Tom et al. (2016) [1], provision of adjustable flaps within the body an oscillating surge converter (OSWEC) allows pass through device. A control system may then open and close waves approaching device exceed preset thresholds. The variable-geometry OSWEC (VG-OSWEC) concept studied in this paper bottom-hinged, rectangular paddle with five elliptical cross-section embedded into face paddle. System ID tests were conducted on VG-OSWEC at 1:14 scale basin. Free decay showed that damping was distinctly nonlinear fully open, natural frequency increased 40% compared closed configuration. Tests regular conditions used develop response amplitude operator for rotational motion about hinge. These results numerical simulations run using WEC-Sim/WAMIT ANSYS AQWA, show strong agreement flap conditions. regular-wave measurements also excitation moment hinge reduced up 60% open. experiments serve demonstrate potential variable geometry design survive harsh ocean environments.