Irregular wave interaction with an offshore OWC wave energy converter

2021 ◽  
Vol 222 ◽  
pp. 108619
Author(s):  
Milad Zabihi ◽  
Said Mazaheri ◽  
Masoud Montazeri Namin ◽  
Ahmad Rezaee Mazyak
Keyword(s):  
Wave Energy ◽  
Wave Interaction ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
Irregular Wave

scholarly journals Analysis of a Two-Body Floating Wave Energy Converter With Particular Focus on the Effects of Power Take-Off and Mooring Systems on Energy Capture

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Made Jaya Muliawan ◽  
Zhen Gao ◽  
Torgeir Moan ◽  
Aurelien Babarit
Keyword(s):  
Wave Energy ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
Mooring Lines ◽  
Energy Capture ◽  
Irregular Wave ◽  
Power Capture ◽  
Actual Operation ◽  
Linear Damping ◽  
Two Bodies

The present paper summarizes analyses of a two-body floating wave energy converter (WEC) to determine the mooring tension and the effect of the mooring system on energy capture. Also, the effect of the power take-off (PTO) is assessed. An axisymmetric Wavebob-type WEC is chosen as the object of investigation. However, the PTO system is modeled in a simplified manner as ideal linear damping and spring terms that couple the motions of the two bodies. The analysis is performed using SIMO, which is a time domain simulation tool that accommodates the simulation of multibody systems with hydrodynamic interactions. In SIMO, docking cone features between the two bodies allow movement as per actual operation, and fenders are applied to represent end stops. Six alternative mooring configurations are applied to investigate the effect of mooring on power capture. Mooring analysis is performed to determine the necessary capacity of mooring lines for each configuration to carry the tension due to the WEC motion in extreme conditions. Hydrodynamic loads are determined using WAMIT. We assumed that the WEC will be operated to capture wave power at the Yeu site in France. The analysis is performed for several regular and irregular wave conditions according to wave data available for that site. Simulations are performed to study the effect of the PTO system, end stops settings and several mooring configurations on power capture.

Experimental Investigation of Irregular Wave Cancellation Using a Cycloidal Wave Energy Converter

2012 ◽  
Author(s):  
Stefan G. Siegel ◽  
Casey Fagley ◽  
Marcus Römer ◽  
Thomas McLaughlin
Keyword(s):  
Wave Energy ◽  
Deep Ocean ◽  
Ocean Waves ◽  
Wave Energy Converter ◽  
Irregular Waves ◽  
Energy Converter ◽  
Irregular Wave ◽  
Wave Measurements ◽  
Wave Heights ◽  
Significant Wave Heights

The ability of a Cycloidal Wave Energy Converter (CycWEC) to cancel irregular deep ocean waves is investigated in a 1:300 scale wave tunnel experiment. A CycWEC consists of one or more hydrofoils attached equidistant to a shaft that is aligned parallel to the incoming waves. The entire device is fully submerged in operation. Wave cancellation requires synchronization of the rotation of the CycWEC with the incoming waves, as well as adjustment of the pitch angle of the blades in proportion to the wave height. The performance of a state estimator and controller that achieve this objective were investigated, using the signal from a resistive wave gage located up-wave of the CycWEC as input. The CycWEC model used for the present investigations features two blades that are adjustable in pitch in real time. The performance of the CycWEC for both a superposition of two harmonic waves, as well as irregular waves following a Bretschneider spectrum is shown. Wave cancellation efficiencies as determined by wave measurements of about 80% for the majority of the cases are achieved, with wave periods varying from 0.4s to 0.75s and significant wave heights of Hs ≈ 20mm. This demonstrates that the CycWEC can efficiently interact with irregular waves, which is in good agreement with earlier results obtained from numerical simulations.

Performance Analysis of a Sea Javelin Wave Energy Converter in Irregular Wave

2019 ◽  
Vol 83 (sp1) ◽  
pp. 932 ◽  
Author(s):  
Hengxu Liu ◽  
Jingtao Ao ◽  
Hailong Chen ◽  
Ming Liu ◽  
Maurizio Collu ◽  
...  
Keyword(s):  
Performance Analysis ◽  
Wave Energy ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
Irregular Wave

Computational Investigation of Irregular Wave Cancelation Using a Cycloidal Wave Energy Converter

2012 ◽  
Author(s):  
Casey P. Fagley ◽  
Jürgen J. Seidel ◽  
Stefan G. Siegel
Keyword(s):  
Wave Energy ◽  
Flow Simulation ◽  
Deep Ocean ◽  
Ocean Waves ◽  
Operating Conditions ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
Incoming Wave ◽  
Wave State ◽  
Irregular Wave

The ability of a Cycloidal Wave Energy Converter (CycWEC) to cancel irregular deep ocean waves is investigated in a time integrated, inviscid potential flow simulation. A CycWEC consists of one or more hydrofoils attached eccentrically to a shaft that is aligned parallel to the incoming waves. The entire device is fully submerged in operation. A Bretschneider spectrum with 40 discrete components is used to model an irregular wave environment in the simulations. A sensor placed up-wave of the CycWEC measures the incoming wave height and provides a signal for the wave state estimator, a non-causal Hilbert transformation, to estimate the instantaneous frequency, phase and amplitude of the irregular wave pattern. A linear control scheme which proportionally controls hydrofoil pitch and compensates for phase delays is adopted. Efficiency for the design Bretschneider spectrum shows more than 99% efficiency, while non-optimum, off design operating conditions still maintain more than 85% efficiency. These results are in agreement with concurrent experimental results obtained at a 1:300 scale.

scholarly journals Modelling of focused wave interaction with wave energy converter models using qaleFOAM 

2020 ◽  
Vol 173 (3) ◽  
pp. 100-118
Author(s):  
Junxian Wang ◽  
Shiqiang Yan ◽  
Qingwei Ma ◽  
Jinghua Wang ◽  
Zhihua Xie ◽  
...  
Keyword(s):  
Wave Energy ◽  
Wave Interaction ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
Focused Wave

scholarly journals Analysis of a Two-Body Floating Wave Energy Converter With Particular Focus on the Effects of Power Take Off and Mooring Systems on Energy Capture

2011 ◽  
Author(s):  
Made Jaya Muliawan ◽  
Zhen Gao ◽  
Torgeir Moan ◽  
Aurelien Babarit
Keyword(s):  
Wave Energy ◽  
The Body ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
Operational Conditions ◽  
Energy Capture ◽  
Irregular Wave ◽  
Actual Operation ◽  
Linear Damping ◽  
Multi Body

The present paper summarizes analyses of a two-body floating wave energy converter (WEC) including the mooring system. An axi-symmetric Wavebob type WEC is chosen as the object of investigation here. However, the PTO system is modeled in a simplified manner as ideal linear damping and spring terms that couples the body 1 and the body 2 motions. The analysis is done using SIMO, a time domain simulation tool which accommodates simulation of multi-body systems with hydrodynamic interactions. In SIMO, docking cone features have been introduced between the two bodies to let them move as per actual operation and fenders are applied to represent end stops. Six alternative mooring configurations are applied to investigate the effect of mooring on power capture. In this paper, the software HydroD using WAMIT for hydrodynamic is used to determine hydrodynamic loads. The analysis is carried out for several regular and irregular wave conditions as representative of operational conditions. Simulations are performed with the purpose to study the effects of power take off (PTO) system, end stops setting and several mooring configurations on power captured by the WEC.

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