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Open Access

Article

29 May 2025

Hydrodynamic Performance and Energy Capture Characteristics of a Floating Inner Rotor Wave Energy Device

The development of efficient wave energy converters (WECs) is essential for harnessing marine renewable energy, particularly in regions with low wave energy flux. This study investigates a floating WEC with an internal eccentric rotor designed to enhance energy capture efficiency. The device consists of a floating body for wave energy absorption, an internal rotor for mechanical-to-hydraulic energy conversion, and a mooring system for stability. A numerical model was developed and validated against wave tank experiments, showing good agreement in peak values and amplitudes. Frequency-domain analysis examined the effects of structural parameters, draft, and center of gravity offset on hydrodynamic characteristics, while time-domain analysis evaluated the impact of rotor mass and power take-off (PTO) damping on energy capture. Multi-parameter optimization led to an improved structural design, increasing instantaneous power output by 150% and total power output by 108%. These findings provide a basis for further optimization of WECs in low-energy wave environments.

Keywords: Wave energy; Wave energy converter; Eccentric inner rotor; Hydrodynamic performance; Energy conversion efficiency
Mar. Energy Res.
2025,
2
(2), 10008; 
Open Access

Article

24 December 2024

Hydrodynamic Performance of a Hybrid Floating Power Dock Combining Multi-Cantilever Type Buoys

This paper proposes a novel three-dimensional oscillating pendulum wave energy converter (WEC) that integrates an oscillating float dock station. The device captures wave energy by utilizing both the pitch and roll motions of its primary float and the pendular motion of a buoy. A time-domain analysis method is used to numerically evaluate the hydrodynamic behavior and energy conversion efficiency of the WEC. In ANSYS AQWA, a multi-cantilever WEC model is employed to address the fluid-solid coupling, calculating the device’s motion response and capturing the width ratio under various environmental conditions. Additionally, by modifying key geometric parameters including float radius, length, and cantilever angle, the study examines the rotation at the articulation point and the capture width ratio variation for different device configurations. Results indicate that the device achieves a maximum capture width ratio at a float radius of approximately 120 mm under T = 1.4 s, and a 130 mm for wave periods of 1.5 s and 1.6 s. The highest average capture width ratio is reached at a power take-off (PTO) damping coefficient of 400 N·s/m. The study further investigates the effect of cantilever angle and float length, aiding in the optimization of these geometric parameters.

Keywords: Wave energy; Hybrid system; Floating dock; Cantilevering type buoy; Potential flow theory; Capture width ratio
Mar. Energy Res.
2024,
1
(1), 10005; 
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