Numerical Analysis and Scaled High Resolution Tank Testing of a Novel Wave Energy Converter

Author(s):  
Ken Rhinefrank ◽  
Al Schacher ◽  
Joe Prudell ◽  
Joao Cruz ◽  
Chad Stillinger ◽  
...  

This paper presents a novel point absorber wave energy converter (WEC), developed by Columbia Power Technologies (COLUMBIA POWER), in addition to the related numerical analysis and scaled wave tank testing. Three hydrodynamic modeling tools are employed to evaluate the performance of the WEC, including WAMIT, GL Garrad Hassan's GH WaveDyn, and OrcaFlex. GH WaveDyn is a specialized numerical code being developed specifically for the wave energy industry. Performance and mooring estimates at full scale are evaluated and optimized, followed by the development of a 1:33 scale physical model. The physical tests of the 1:33 scale model WEC were conducted at the multidirectional wave basin of Oregon State University's O.H. Hinsdale Wave Research Laboratory, in conjunction with the Northwest National Marine Renewable Energy Center (NNMREC). This paper concludes with an overview of the next steps for the modeling program and future experimental test plans.

Author(s):  
Ken Rhinefrank ◽  
Al Schacher ◽  
Joe Prudell ◽  
Joao Cruz ◽  
Nuno Jorge ◽  
...  

A novel point absorber wave energy converter (WEC) is being developed by Columbia Power Technologies, LLC (CPT). Numerical and physical experiments have been performed by Columbia Power, Garrad Hassan and Partners (GH) and Oregon State University (OSU). Three hydrodynamic modeling tools including WAMIT, GH WaveFarmer, and OrcaFlex are used to evaluate the performance of the WEC. GH WaveFarmer is a specialized numerical code being developed specifically for the wave energy industry. Performance and mooring estimates at full scale were initially evaluated and optimized, which were then followed by the development of a 1/33rd scale physical model to obtain comparable datasets, aiming to validate the predictions and reduce the uncertainty associated with other numerical model results. The tests of the 1/33rd scale model of the CPT WEC were recently carried out at the multi-directional wave basin of the O.H. Hinsdale Wave Research Laboratory (HWRL), in conjunction with the Northwest National Marine Renewable Energy Center (NNMREC) at OSU. This paper presents details of the modeling program and progress to date. Emphasis is given to the coupling of WAMIT with GH WaveFarmer for performance estimates and the coupling of WAMIT with the OrcaFlex model for mooring load estimates. An overview of the novel 3-body WEC, including operation and mooring system, is also presented. The 1/33rd scale model functionality is described including an overview of the experimental setup at the basin. Comparisons between the numerical and experimental results are shown for both regular and irregular waves and for several wave headings and dominant directions using a number of spreading functions. The paper concludes with an overview of the next steps for the modeling program and future experimental test plans.


Author(s):  
Ken Rhinefrank ◽  
Al Schacher ◽  
Joe Prudell ◽  
Erik Hammagren ◽  
Zhe Zhang ◽  
...  

This paper presents a novel 1:7 scale point absorber wave energy converter (WEC), developed by Columbia Power Technologies (COLUMBIA POWER). Four hydrodynamic modeling tools were employed in the scaled development and the optimization process of the WEC, including WAMIT, Garrad Hassan’s GH WaveFarmer, OrcaFlex and ANSYS AQWA. The numerical analysis development is discussed, and the performance and mooring estimates at 1:7 scale and full scale are evaluated and optimized. The paper includes the development of the 1:7 scale physical model and the associated WEC field testing in Puget Sound, WA.


2021 ◽  
Vol 9 (2) ◽  
pp. 228
Author(s):  
Alana Pols ◽  
Eric Gubesch ◽  
Nagi Abdussamie ◽  
Irene Penesis ◽  
Christopher Chin

This investigation focuses on the modelling of a floating oscillating water column (FOWC) wave energy converter with a numerical code (ANSYS AQWA) based on potential flow theory. Free-floating motions predicted by the numerical model were validated against experimental data extrapolated from a 1:36 scale model device in regular and irregular sea states. Upon validation, an assessment of the device’s motions when dynamically coupled with a four-line catenary mooring arrangement was conducted at different incident wave angles and sea states ranging from operational to survivable conditions, including the simulation of the failure of a single mooring line. The lack of viscosity in the numerical modelling led to overpredicted motions in the vicinity of the resonant frequencies; however, the addition of an external linear damping coefficient was shown to be an acceptable method of mitigating these discrepancies. The incident wave angle was found to have a limited influence on the magnitudes of heave, pitch, and surge motions. Furthermore, the obtained results indicated that the mooring restoring force is controlled by the forward mooring lines under the tested conditions.


Author(s):  
Yuzhu Li ◽  
Heather Peng ◽  
Wei Qiu ◽  
Brian Lundrigan ◽  
Tim Gardiner

SeaWEED (Sea Wave Energy Extraction Device) is a multi-body floating wave energy converter (WEC) with hinged joints developed by Grey Island Energy Inc. (GIE) in Canada. Initial conceptual studies have been carried out to evaluate the performance of the first generation device by testing a 1:16 scale model in a wave basin. The experimental results were compared with the numerical solutions. Based on the experimental studies, improvements were made and a second generation model with a new geometry of the hull and a new connection structure was developed. This paper is mainly focused on the numerical analysis and optimization of the second generation SeaWEED model. In the numerical studies, the hydraulic power take-off (PTO) system was simulated by a linear spring damper system coupled with the motion of the hinged bodies. The vertical hinge motion was computed at a series of wave periods using WAMIT. Optimization was focused on the PTO damping and the geometrical parameters in terms of the draft and the length of the truss structure between hinged bodies by using the response surface method. An optimal combination of length, draft and PTO damping was recommended for an intended operation location.


2015 ◽  
pp. 437-443
Author(s):  
Harry Bingham ◽  
Robert Read ◽  
Frederik Jakobsen ◽  
Morten Simonsen ◽  
Pablo Guillen ◽  
...  

Author(s):  
Andrei Santos ◽  
Filipe Branco Teixeira ◽  
Liércio Isoldi ◽  
jeferson Avila Souza ◽  
Mateus das Neves Gomes ◽  
...  

Author(s):  
Frances M. Judge ◽  
Eoin Lyden ◽  
Michael O'Shea ◽  
Brian Flannery ◽  
Jimmy Murphy

Abstract This research presents a methodology for carrying out uncertainty analysis on measurements made during wave basin testing of an oscillating water column wave energy converter. Values are determined for Type A and Type B uncertainty for each parameter of interest, and uncertainty is propagated using the Monte Carlo method to obtain an overall Expanded Uncertainty with a 95% confidence level associated with the Capture Width Ratio of the device. An analysis into the impact of reflections on the experimental results reveals the importance of identifying the incident and combined wave field at each measurement location used to determine device performance, in order to avoid misleading results.


Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2364 ◽  
Author(s):  
Hengxu Liu ◽  
Feng Yan ◽  
Fengmei Jing ◽  
Jingtao Ao ◽  
Zhaoliang Han ◽  
...  

This paper introduces a new point-absorber wave energy converter (WEC) with a moonpool buoy—the moonpool platform wave energy converter (MPWEC). The MPWEC structure includes a cylinder buoy and a moonpool buoy and a Power Take-off (PTO) system, where the relative movement between the cylindrical buoy and the moonpool buoy is exploited by the PTO system to generate energy. A 1:10 scale model was physically tested to validate the numerical model and further prove the feasibility of the proposed system. The motion responses of and the power absorbed by the MPWEC studied in the wave tank experiments were also numerically analyzed, with a potential approach in the frequency domain, and a computational fluid dynamics (CFD) code in the time domain. The good agreement between the experimental and the numerical results showed that the present numerical model is accurate enough, and therefore considering only the heave degree of freedom is acceptable to estimate the motion responses and power absorption. The study shows that the MPWEC optimum power extractions is realized over a range of wave frequencies between 1.7 and 2.5 rad/s.


Author(s):  
Aurélien Babarit ◽  
Benjamin Gendron ◽  
Jitendra Singh ◽  
Cécile Mélis ◽  
Philippe Jean

Since 2009, SBM Offshore has been developing the S3 Wave Energy Converter (S3 WEC). It consists in a long flexible tube made of an Electro-Active Polymer (EAP). Thus, the structural material is also the Power Take Off (PTO). In order to optimize the S3 WEC, a hydro-elastic numerical model able to predict the device dynamic response has been developed. The inner flow, elastic wall deformations and outer flow are taken into account in the model under the following assumptions: Euler equation is used for the inner flow. The flow is also assumed to be uniform. Elastic deformation of the wall tube is linearized. The outer flow is modeled using linear potential theory. These equations have been combined in order to build the numerical model. First, they are solved in the absence of the outer fluid in order to obtain the modes of response of the device. Secondly, the outer fluid is taken into account and the equation of motion is solved by making use of modal expansion. Meanwhile, experimental validation tests were conducted in the ocean basin at Ecole Centrale De Nantes. The scale model is 10m long tube made of EAP. The tube deformations were measured using the electro-active polymer. The model was also equipped with sensors in order to measure the inner pressure. Comparisons of the deformation rate between the numerical model and experimental results show good agreement, provided that the wall damping is calibrated. Eventually, results of a technico-economical parametric study of the dimensions of the device are presented.


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