Constructal Design Applied to Geometric Shapes Analysis of Wave Energy Converters

2021 ◽  
Vol 407 ◽  
pp. 147-160
Author(s):  
Mateus das Neves Gomes ◽  
Heloiza Salvador ◽  
Felipe Magno ◽  
Amanda A. Rodrigues ◽  
Elizaldo Domingues Santos ◽  
...  
Keyword(s):  
Wave Energy ◽  
Wave Spectrum ◽  
Geometrical Shape ◽  
Peak Period ◽  
Geometric Shapes ◽  
Constructal Design ◽  
Wave Energy Converters ◽  
Ocean Wave Energy ◽  
Vof Model ◽  
Shape Influence

This paper deals with numerical simulation and the geometrical analysis of an ocean Wave Energy Converter (WEC), which has as the operating principle the Oscillating Water Column (OWC). The goal was to evaluate the geometric shape influence of the OWC chamber in the hydropneumatic power available. Therefore, four geometric shapes were analyzed: i) Rectangle (RT), ii) Trapezium (TP), iii) Inverted Trapezium (TI) and iv) Double Trapezium (DT). For this, the OWC device was subject to a JONSWAP wave spectrum with peak period (TS) equal to 7.5 s and peak wave height (HS) equal to 1.5 m. To do so, Constructal Design was employed varying the Degree Of Freedom (DOF) H1/L (ratio between the height and length of the OWC chamber entrance). The problem constraints were the entrance area and the total area of the OWC chamber that were kept constant. For the numerical solution a Computational Fluid Dynamics (CFD) code, based on the Finite Volume Method (FVM),de0 was used. The multiphase Volume of Fluid (VOF) model was applied to tackle with the water-air interaction. The results indicated that when the Rectangle (RT) geometrical shape was employed an improvement of nearly 99% was achieved.

scholarly journals HF Radars for Wave Energy Resource Assessment Offshore NW Spain

2021 ◽  
Vol 13 (11) ◽  
pp. 2070
Author(s):  
Ana Basañez ◽  
Vicente Pérez-Muñuzuri
Keyword(s):  
Wave Energy ◽  
Numerical Models ◽  
Wave Spectrum ◽  
Energy Resource ◽  
Electrical Energy ◽  
Resource Assessment ◽  
Electricity Production ◽  
Statistical Validation ◽  
Wave Energy Converters ◽  
Energy Converters

Wave energy resource assessment is crucial for the development of the marine renewable industry. High-frequency radars (HF radars) have been demonstrated to be a useful wave measuring tool. Therefore, in this work, we evaluated the accuracy of two CODAR Seasonde HF radars for describing the wave energy resource of two offshore areas in the west Galician coast, Spain (Vilán and Silleiro capes). The resulting wave characterization was used to estimate the electricity production of two wave energy converters. Results were validated against wave data from two buoys and two numerical models (SIMAR, (Marine Simulation) and WaveWatch III). The statistical validation revealed that the radar of Silleiro cape significantly overestimates the wave power, mainly due to a large overestimation of the wave energy period. The effect of the radars’ data loss during low wave energy periods on the mean wave energy is partially compensated with the overestimation of wave height and energy period. The theoretical electrical energy production of the wave energy converters was also affected by these differences. Energy period estimation was found to be highly conditioned to the unimodal interpretation of the wave spectrum, and it is expected that new releases of the radar software will be able to characterize different sea states independently.

Constructal Design of Wave Energy Converters

2012 ◽  
pp. 275-294 ◽  
Author(s):  
E. D. dos Santos ◽  
B. N. Machado ◽  
N. Lopes ◽  
J. A. Souza ◽  
P. R. F. Teixeira ◽  
...  
Keyword(s):  
Wave Energy ◽  
Constructal Design ◽  
Wave Energy Converters ◽  
Energy Converters

Ocean Wave Energy Converters - A Perspective

2012 ◽  
Vol 36 (5) ◽  
pp. 707-715 ◽  
Author(s):  
Nanjundan Parthasarathy ◽  
Kui Ming Li ◽  
Yoon-Hwan Choi ◽  
Yeon-Won Lee
Keyword(s):  
Wave Energy ◽  
Ocean Wave ◽  
Wave Energy Converters ◽  
Ocean Wave Energy ◽  
Energy Converters

A review on front end conversion in ocean wave energy converters

2015 ◽  
Vol 9 (3) ◽  
pp. 297-310 ◽  
Author(s):  
Nagulan Santhosh ◽  
Venkatesan Baskaran ◽  
Arunachalam Amarkarthik
Keyword(s):  
Wave Energy ◽  
Ocean Wave ◽  
Wave Energy Converters ◽  
Ocean Wave Energy ◽  
Front End ◽  
Energy Converters

Computational Modeling of Rolling Wave-Energy Converters in a Viscous Fluid1

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Yichen Jiang ◽  
Ronald W. Yeung
Keyword(s):  
Wave Energy ◽  
Performance Metrics ◽  
Vortex Method ◽  
Inviscid Fluid ◽  
Mathematical Form ◽  
Wave Energy Converters ◽  
Ocean Wave Energy ◽  
Real Fluid ◽  
Fluid Theory ◽  
Energy Absorbing

The performance of an asymmetrical rolling cam as an ocean-wave energy extractor was studied experimentally and theoretically in the 70s. Previous inviscid-fluid theory indicated that energy-absorbing efficiency could approach 100% in the absence of real-fluid effects. The way viscosity alters the performance is examined in this paper for two distinctive rolling-cam shapes: a smooth “Eyeball Cam (EC)” with a simple mathematical form and a “Keeled Cam (KC)” with a single sharp-edged keel. Frequency-domain solutions in an inviscid fluid were first sought for as baseline performance metrics. As expected, without viscosity, both shapes, despite their differences, perform exceedingly well in terms of extraction efficiency. The hydrodynamic properties of the two shapes were then examined in a real fluid, using the solution methodology called the free-surface random-vortex method (FSRVM). The added inertia and radiation damping were changed, especially for the KC. With the power-take-off (PTO) damping present, nonlinear time-domain solutions were developed to predict the rolling motion, the effects of PTO damping, and the effects of the cam shapes. For the EC, the coupled motion of sway, heave and roll in waves was investigated to understand how energy extraction was affected.

scholarly journals A Survey of Power Take-off Systems of Ocean Wave Energy Converters

2019 ◽  
Author(s):  
Zhenwei Liu ◽  
Ran Zhang ◽  
Han Xiao ◽  
Xu Wang
Keyword(s):  
Energy Conversion ◽  
Wave Energy ◽  
Clean Energy ◽  
Ocean Wave ◽  
Direct Drive ◽  
Wave Energy Conversion ◽  
Drive Power ◽  
Wave Energy Converters ◽  
Ocean Wave Energy ◽  
Energy Converters

Ocean wave energy conversion as one of the renewable clean energy sources is attracting the research interests of many people. This review introduces different types of power take-off technology of wave energy converters. The main focus is the linear direct drive power take-off devices as they have the advantages for ocean wave energy conversion. The designs and optimizations of power take-off systems of ocean wave energy converters have been studied from reviewing the recently published literature. Also, the simple hydrodynamics of wave energy converters have been reviewed for design optimization of the wave energy converters at specific wave sites. The novel mechanical designs of the power take-off systems have been compared and investigated in order to increase the energy harvesting efficiency.

Analysis and Design of Twin Gyroscopes for Ocean-Wave Energy Converters and Ship Roll-Stabilizers

2019 ◽  
Author(s):  
Hidenori Murakami ◽  
Takeyuki Ono
Keyword(s):  
Wave Energy ◽  
Equations Of Motion ◽  
Ocean Wave ◽  
Configuration Spaces ◽  
Wave Energy Converters ◽  
Ocean Wave Energy ◽  
Ship Roll ◽  
Gyroscopic Systems ◽  
Lagrange’S Method ◽  
Energy Converters

Abstract Twin-gyroscopic systems are designed for ocean-wave energy converters and ship roll-stabilizers to double desirable gyroscopic effects and eliminate undesirable reaction torques. In deriving analytical equations of motion, the configuration spaces of gyroscopic systems are defined by using body-attached moving frames. The moving frame of each constituent body is defined by its inertial coordinates of the center of mass and a rotation matrix which expresses the attitude of its coordinate axes from the inertial coordinate axes. Therefore, to utilize powerful Lagrange’s method, it is extended to accommodate rotation matrices in configuration spaces and allow angular velocities as generalized velocities. First, in the paper, to identify undesirable reaction torques of gyroscopic systems and find a scheme to eliminate them, we present the basics of a reaction wheel. Second, to identify the desirable gyroscopic effect, we consider a control moment gyroscope and derive the equations of motion using the extended Lagrange’s method. In addition, the equations of motion are also derived by using the Newton-Euler method, where action and reaction torques are explicitly expressed. The comparison of the resulting equations derived by the two methods reveals the simplicity of Lagrange’s method in treating actuating motor torques and how the effects of reaction torques are implicitly included in the variationally derived equations. Finally, the equations of motion for a twin-gyroscopic system are obtained by incorporating the scheme to eliminate the undesirable reaction torques.

Analysis of rotating ocean wave energy converters.

2010 ◽  
Vol 128 (4) ◽  
pp. 2347-2347
Author(s):  
J. Gregory McDaniel ◽  
Alexandra M. Shivers
Keyword(s):  
Wave Energy ◽  
Ocean Wave ◽  
Wave Energy Converters ◽  
Ocean Wave Energy ◽  
Energy Converters

Numerical Analysis and Parameter Optimization of a Portable Two-Body Attenuator Wave Energy Converter

2021 ◽  
Author(s):  
Joseph Capper ◽  
Jia Mi ◽  
Qiaofeng Li ◽  
Lei Zuo
Keyword(s):  
Drag Coefficient ◽  
Wave Energy ◽  
Degree Of Freedom ◽  
Wave Energy Converters ◽  
Ocean Wave Energy ◽  
Significant Difference ◽  
Power Maximization ◽  
Study Power ◽  
Body Cross Section ◽  
Three Degree Of Freedom

Abstract Easily portable, small-sized ocean wave energy converters (WECs) may be used in many situations where large-sized WEC devices are not necessary or practical. Power maximization for small-sized WECs amplifies challenges that are not as difficult with large-sized devices, especially tuning the device’s natural frequency to match the wave frequency and achieve resonance. In this study, power maximization is performed for a small-sized, two-body attenuator WEC with a footprint constraint of about 1m. A thin, submerged tuning plate is added to each body to increase added mass without significantly increasing hydrostatic stiffness in order to reach resonance. Three different body cross-section geometries are analyzed. Device power absorption is determined through time domain simulations using WEC-Sim with a simplified two-degree-of-freedom (2DOF) model and a more realistic three-degree-of-freedom (3DOF) model. Different drag coefficients are used for each geometry to explore the effect of drag. A mooring stiffness study is performed with the 3DOF model to investigate the mooring impact. Based on the 2DOF and 3DOF power results, there is not a significant difference in power between the shapes if the same drag coefficient is used, but the elliptical shape has the highest power after assigning a different approximate drag coefficient to each shape. The mooring stiffness study shows that mooring stiffness can be increased in order to increase relative motion between the two bodies and consequently increase the power.

On the Importance of High–Fidelity Numerical Modelling of Ocean Wave Energy Converters under Controlled Conditions

2022 ◽  
Author(s):  
C. Windt
Keyword(s):  
Numerical Modelling ◽  
Wave Energy ◽  
Numerical Models ◽  
Ocean Wave ◽  
High Fidelity ◽  
Wave Energy Converters ◽  
Ocean Wave Energy ◽  
Controlled Conditions ◽  
Hydrodynamic Wave ◽  
Energy Converters

Abstract. Numerical modelling tools are commonly applied during the development and optimisation of ocean wave energy converters (WECs). Models are available for the hydrodynamic wave structure interaction, as well as the WEC sub–systems, such as the power take–off (PTO) model. Based on the implemented equations, different levels of fidelity are available for the numerical models. Specifically under controlled conditions, with enhance WEC motion, it is assumed that non-linearities are more prominent, re- quiring the use of high–fidelity modelling tools. Based on two different test cases for two different WECs, this paper highlights the importance of high–fidelity numerical modelling of WECs under controlled conditions.

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