Comparison Between Numerical Modeling and Experimental Testing of a Point Absorber WEC Using Linear Power Take-Off System

2012 ◽  
Author(s):  
Andrew S. Zurkinden ◽  
Morten Kramer ◽  
Mahdi Teimouri Teimouri ◽  
Marco Alves
Keyword(s):  
Numerical Model ◽  
Wave Energy ◽  
Numerical Models ◽  
Experimental Testing ◽  
Irregular Waves ◽  
Laboratory Model ◽  
Point Absorber ◽  
Wave Energy Converters ◽  
Wave Conditions ◽  
Energy Converters

Currently, a number of wave energy converters are being analyzed by means of numerical models in order to predict the electrical power generation under given wave conditions. A common characteristic of this procedure is to integrate the loadings from the hydrodynamics, power take-off and mooring systems into a central wave to wire model. The power production then depends on the control strategy which is applied to the device. The objective of this paper is to develop numerical methods for motion analysis of marine structures with a special emphasis on wave energy converters. Two different time domain models are applied to a point absorber system working in pitch mode only. The device is similar to the well-known Wavestar prototype located in the Danish North Sea. A laboratory model has been set up in order to validate the numerical simulations of the dynamics. Wave Excitation force and the response of the device for regular and irregular waves were measured. Good correspondence is found between the numerical and the physical model for relatively mild wave conditions. For higher waves the numerical model seems to underestimate the response of the device due to its linear fluid-structure interaction assumption and linearized equation of motion. The region over which the numerical model is valid will be presented in terms of non-dimensional parameters describing the different wave states.

scholarly journals Ηydrodynamic Response and Produced Power of a Combined Structure Consisting of a Spar and Heaving Type Wave Energy Converters

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 225
Author(s):  
Constantine Michailides
Keyword(s):  
Numerical Model ◽  
Wave Energy ◽  
Hydrodynamic Interaction ◽  
Numerical Models ◽  
Interaction Effects ◽  
Irregular Waves ◽  
Wave Power ◽  
Wave Energy Converters ◽  
Combined Structure ◽  
Energy Converters

During the past years, researchers have studied both numerically and experimentally multibody wave-wind combined energy structures supporting wind turbines and different types of Wave Energy Converters (WECs); rigid body hydrodynamic assumptions have been adopted so far for the development of their numerical models and the assessment of their produced power. In the present paper a numerical model that is based on the use of generalized modes addressing wave-structure interaction effects for the case of a multibody wave-wind combined structure is developed and presented. Afterwards, the developed numerical model is used for the assessment of the hydrodynamic response and the prediction of the produced power of different possible configurations of the updated WindWEC concept which consists of a spar supporting a wind turbine and one, two, three or four heaving type WEC buoys. The combined effects of the center-to-center distance of the WEC and spar platform, the number of the WECs and the grid configuration of spar and WECs on the hydrodynamic interaction between the different floating bodies, spar and WEC buoys, and consequently on their response and wave power production are examined for regular and irregular waves. Strong hydrodynamic interaction effects exist for small distance between spar and WECs that result to the decrease of the produced power. Power matrices of the updated WindWEC concept are presented for all examined configurations with different number of WECs. Moreover, the annual produced power of the updated WindWEC in two sites is estimated and presented. The generalized modes analysis presented in this paper is generic and can be used for the early stage assessment of wave-wind combined energy structures with low computational cost. The updated WindWEC can be used in sea sites with different environmental characteristics while extracting valuable amount of wave power.

scholarly journals Array modeling and testing of fixed OWC type Wave Energy Converters

2020 ◽  
Vol 3 (3) ◽  
pp. 137-143
Author(s):  
Bret Bosma ◽  
Ted Brekken ◽  
Pedro Lomonaco ◽  
Bryony DuPont ◽  
Chris Sharp ◽  
...  
Keyword(s):  
Numerical Model ◽  
Wave Energy ◽  
Average Power ◽  
Irregular Waves ◽  
Regular Waves ◽  
Wave Energy Converters ◽  
Phase Errors ◽  
Array Optimization ◽  
Tank Test ◽  
Energy Converters

If wave energy technology is to mature to commercial success, array optimization could play a key role in that process. This paper outlines physical and numerical modeling of an array of five oscillating water column wave energy converters. Numerical model simulations are compared with experimental tank test data for a non-optimal and optimal array layout. Results show a max increase of 12% in average power for regular waves, and 7% for irregular waves between the non-optimized and optimized layouts. The numerical model matches well under many conditions; however, improvement is needed to adjust for phase errors. This paper outlines the process of numerical and physical array testing, providing methodology and results helpful for researchers and developers working with wave energy converter arrays.

Experimental and numerical comparisons of self-reacting point absorber wave energy converters in irregular waves

2019 ◽  
Vol 173 ◽  
pp. 716-731 ◽  
Author(s):  
Scott J. Beatty ◽  
Bryce Bocking ◽  
Kush Bubbar ◽  
Bradley J. Buckham ◽  
Peter Wild
Keyword(s):  
Wave Energy ◽  
Irregular Waves ◽  
Numerical Comparisons ◽  
Point Absorber ◽  
Wave Energy Converters ◽  
Energy Converters

Coupled dynamic analysis of hybrid offshore wind turbine and wave energy converter

2021 ◽  
pp. 1-40
Author(s):  
Rony JS ◽  
Debabrata Karmakar
Keyword(s):  
Dynamic Analysis ◽  
Wind Turbine ◽  
Wave Energy ◽  
Wave Energy Converter ◽  
Offshore Wind ◽  
Irregular Waves ◽  
Energy Converter ◽  
Point Absorber ◽  
Wave Energy Converters ◽  
Energy Converters

Abstract The combined offshore wind and wave energy on an integrated platform is an economical solution for the offshore energy industry as they share the infrastructure and ocean space. The study presents the dynamic analysis of the Submerged Tension-Leg Platform (STLP) combined with a heaving-type point absorber wave energy converter (WEC). The feasibility study of the hybrid concept is performed using the aero-servo-hydro-elastic simulation tool FAST. The study analyses the responses of the combined system to understand the influence of the WECs on the STLP platform for various operating conditions of the wind turbine under regular and irregular waves. A positive synergy is observed between the platform and the WECs, and the study also focuses on the forces and moments developed at the interface of the tower and platform to understand the effect of wind energy on the turbine tower and importance of motion amplitudes on the performance of the combined platform system. The mean and standard deviation for the translation and rotational motions of combined wind and wave energy converters are determined for different sea states under both regular and irregular waves to analyse the change in responses of the structure. The study observed a reduction in motion amplitudes of the hybrid floating system with the addition of the wave energy converters around the STLP floater to improve the energy efficiency of the hybrid system. The study helps in understanding the best possible arrangement of point absorber type wave energy converters at the conceptual stage of the design process.

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.

Numerical Modeling to Aid in the Structural Health Monitoring of Wave Energy Converters

2013 ◽  
Vol 569-570 ◽  
pp. 595-602 ◽  
Author(s):  
William Finnegan ◽  
Jamie Goggins
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Wave Energy ◽  
Numerical Models ◽  
Wave Structure ◽  
Ocean Waves ◽  
Test Site ◽  
Structural Health ◽  
Wave Energy Converters ◽  
Energy Converters

A vital aspect of ensuring the cost effectiveness of wave energy converters (WECs) is being able to monitor their performance remotely through structural health monitoring, as these devices are deployed in very harsh environments in terms of both accessibility and potential damage to the devices. The WECs are monitored through the use of measuring equipment, which is strategically placed on the device. This measured data is then compared to the output from a numerical model of the WEC under the same ocean wave conditions. Any deviations would suggest that there are problems or issues with the WEC. The development of accurate and effective numerical models is necessary to minimise the number of times the visual, or physical, inspection of a deployed WEC is required. In this paper, a numerical wave tank model is, first, validated by comparing the waves generated to those generated experimentally using the wave flume located at the National University of Ireland, Galway. This model is then extended so it is suitable for generating real ocean waves. A wave record observed at the Atlantic marine energy test site has been replicated in the model to a high level of accuracy. A rectangular floating prism is then introduced into the model in order to explore wave-structure interaction. The dynamic response of the structure is compared to a simple analytical solution and found to be in good agreement.

Experimental and numerical comparisons of self-reacting point absorber wave energy converters in regular waves

2015 ◽  
Vol 104 ◽  
pp. 370-386 ◽  
Author(s):  
Scott J. Beatty ◽  
Matthew Hall ◽  
Bradley J. Buckham ◽  
Peter Wild ◽  
Bryce Bocking
Keyword(s):  
Wave Energy ◽  
Regular Waves ◽  
Numerical Comparisons ◽  
Point Absorber ◽  
Wave Energy Converters ◽  
Energy Converters

Performance assessments of the fully submerged sphere and cylinder point absorber wave energy converters

2019 ◽  
Vol 33 (13) ◽  
pp. 1950168 ◽  
Author(s):  
Qianlong Xu ◽  
Ye Li ◽  
Yingkai Xia ◽  
Weixing Chen ◽  
Feng Gao
Keyword(s):  
Wave Height ◽  
Wave Energy ◽  
Interaction Analysis ◽  
Wave Power ◽  
Viscous Damping ◽  
Power Performance ◽  
Point Absorber ◽  
Wave Energy Converters ◽  
Submerged Sphere ◽  
Energy Converters

Fully submerged sphere and cylinder point absorber (PA), wave energy converters (WECs) are analyzed numerically based on linearized potential flow theory. A boundary element method (BEM) (a radiation–diffraction panel program for wave-body interactions) is used for the basic wave-structure interaction analysis. In the present numerical model, the viscous damping is modeled by an equivalent linearized damping which extracts the same amount of wave energy over one cycle as the conventional quadratic damping term. The wave power capture width in each case is predicted. Comparisons are also made between the sphere and cylinder PAs which have identical geometrical scales and submerged depths. The results show that: (i) viscous damping has a greater influence on wave power performance of the cylinder PA than that of the sphere PA; (ii) the increasing wave height reduces wave power performance of PAs; (iii) the cylinder PA has a better wave power performance compared to the sphere PA in larger wave height scenarios, which indicates that fully submerged cylinder PA is a preferable prototype of WEC.

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