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Numerical Modelling of Double Slit Caisson Breakwater Integrated Oscillating Water Column Wave Energy Converter with Modal Superposition Method
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作者 Mitsumasa Iino Hisashi Endo 《Open Journal of Fluid Dynamics》 CAS 2023年第2期92-103,共12页
Oscillating water column wave energy converter is a power generation device in which ocean waves excite the oscillation of the water surface in an air chamber, which generates fluctuations in air pressure and rotate a... Oscillating water column wave energy converter is a power generation device in which ocean waves excite the oscillation of the water surface in an air chamber, which generates fluctuations in air pressure and rotate air turbine generator(s). The oscillation of the fluid in the air chamber is a fluid oscillation phenomenon with a natural period, similar to fluid oscillation in a container such as sloshing. Previous research has shown that for an oscillating water column with a single air chamber submerged in water, the oscillation characteristics can be modeled as a one-degree-of-freedom oscillation system that takes only a single oscillation mode into account. However, a double-slit breakwater integrated oscillating water column wave energy converter using two water columns of the breakwater separated by slit walls, has been verified to have two resonance periods. In this study, the free oscillating motion of the oscillating water column wave energy converter using the double-slit breakwater is modeled by modal superposition method including the first-order and second-order modes of vertical motion of the two water surfaces. The result from the simulation is similar to the result of the free vibration experiment. 展开更多
关键词 Fluid Oscillation Wave Energy oscillating water column Modal Analysis
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Numerical Study of Air Chamber for Oscillating Water Column Wave Energy Convertor 被引量:7
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作者 刘臻 HYUN Beom-Soo HONG Keyyong 《China Ocean Engineering》 SCIE EI 2011年第1期169-178,共10页
Oscillating Water Column (OWC) wave energy converting system is one of the most widely used facilities all over the world. The air chamber is utilized to convert the wave energy into the pneumatic energy. The numeri... Oscillating Water Column (OWC) wave energy converting system is one of the most widely used facilities all over the world. The air chamber is utilized to convert the wave energy into the pneumatic energy. The numerical wave tank based on the two-phase VOF model is established in the present study toinvestigate the operating performance of OWC air chamber. The RANS equations, standard k-ε turbulence model and dynamic mesh technology are employed in the numerical model. The effects of incident wave conditions and shape parameters on the wave energy converting efficiency are studied and the capability of the present numerical wave tank on the corresponding engineering application is validated. 展开更多
关键词 oscillating water column numerical wave tank operating performance air chamber shape parameter
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Experimental Investigation on a Fixed Oscillating Water Column with an Impulse Turbine for Wave Energy Conversion
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作者 Tengen Murakami Yasutaka Imai +1 位作者 Shuichi Nagata Manabu Takao 《Journal of Energy and Power Engineering》 2020年第1期16-25,共10页
A fixed oscillating water column(OWC)-type wave energy converter consists of an air chamber,an air turbine and a generator.The energy conversion processes are the primary conversion in an air chamber and the secondary... A fixed oscillating water column(OWC)-type wave energy converter consists of an air chamber,an air turbine and a generator.The energy conversion processes are the primary conversion in an air chamber and the secondary conversion of the turbine.For the practical use,it is necessary to develop a design method which can consider the incident wave motion,the motion of the internal free surface affected in the structure such as a partly submerged wall,the fluctuation of air pressure in an air chamber,and the rotation of the air turbine.At here,the authors carried out the wave tank tests using the model OWC equipped with the impulse turbine and a generator to obtain the experimental data needed to make this design method.As the result,the efficiencies of the three cases with different speed ratio between generator and turbine,and the effects of the curtain wall depth and the wave length on the energy conversion performance were clarified. 展开更多
关键词 Impulse turbine oscillating water column primary conversion secondary conversion wave energy
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Experimental and numerical analysis of multi-chamber oscillating water column devices
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作者 Jorge Gadelho Kourosh Rezanejad C.Guedes Soares 《Journal of Hydrodynamics》 SCIE EI CSCD 2024年第3期492-503,共12页
A review of multi-chamber oscillating water column(OWC)device designs is presented.Two significant variations of these devices are discussed,onshore OWC(OOWC)and a floating OWC(FOWC).The efficiency results of several ... A review of multi-chamber oscillating water column(OWC)device designs is presented.Two significant variations of these devices are discussed,onshore OWC(OOWC)and a floating OWC(FOWC).The efficiency results of several theoretical studies based on low-and high-fidelity numerical models are presented and compared with the model scale results.Generally,low-fidelity numerical models are very fast to run,but their accuracy is limited compared with high-fidelity numerical models.Scaled model experiments usually give results much more accurate than numerical models,but they need adequate facilities and are very expensive.In the case of the OOWC,all models show a similar trend of total efficiency,but while the analytical model shows a maximum value of around 90%efficiency,the CFD model shows 60%,and the experiments only go up to 40%.The main reason is connected with the mathematical simplifications and assumptions that do not represent all the hydrodynamic and aerodynamic processes between the water,air,and structure.For the case of the FOWC,interestingly,the experimental results show a maximum efficiency of almost 100%,while the analytical model only predicts a maximum of 80%.The efficiency seems highly dependent on the heave motion resonance of the entire device,where the analytical model fails to predict this natural frequency. 展开更多
关键词 Wave energy converters oscillating water column(OWC) multi-chambers experimental modelling numerical modelling
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Numerical analysis of a projecting wall type oscillating water column(PW-OWC)wave energy converter in regular waves
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作者 Lei Tan Ruiyuan Chang Tomoki Ikoma 《Journal of Hydrodynamics》 SCIE EI CSCD 2024年第3期479-491,共13页
Oscillating water column(OWC)based wave energy absorption devices are classic which have been widely used for harnessing ocean wave energy.This paper presents a numerical study on a projecting wall(PW)type OWC wave en... Oscillating water column(OWC)based wave energy absorption devices are classic which have been widely used for harnessing ocean wave energy.This paper presents a numerical study on a projecting wall(PW)type OWC wave energy converter in regular waves.The computational fluid dynamics(CFD)modelling of a stationary floating PW-OWC model in a three-dimensional wave flume is achieved by the software Flow-3D.Numerical analyses are carried out based on CFD simulations and the linear potential flow solutions with modifications to account for turbine-induced damping.The present numerical solutions are validated against our previous experimental data.It is found that both the CFD and modified linear potential flow predictions are in reasonably good agreements with the experimental data in the first order results of OWC and air pressure responses.When the nonlinear responses are included in the result,the modified linear potential flow solution is found to slightly under-estimate the wave energy conversion performance at long wavelengths.Regarding the airflows above and below the chamber orifice,the CFD results suggest that they are almost unidirectional,oscillating in not only the base frequency but also subharmonic and ultraharmonic frequencies.The evolution of the OWC responses during an entire period and the phase analysis based on CFD simulations are presented.The phase results provide the crucial evidence to the reasonability of the physics-based modification of the potential flow model in modelling of OWCs.The present results and analysis are expected to be beneficial to the understanding on the physical mechanism of OWCs and the design of phase control strategies. 展开更多
关键词 Computational fluid dynamics(CFD)simulation hydrodynamic analysis oscillating water column(OWC)damping orifice airflow phase difference
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Experimental validation of double-fed induction generator in oscillating water column using circulatory system-based optimization
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作者 Basem E.Elnaghi Ahmed M.Ismaiel +2 位作者 Fathy El Sayed Abdel-Kader Reham H.Mohammed M.N.Abelwhab 《Clean Energy》 EI CSCD 2024年第2期127-143,共17页
This paper validates the optimal operation for a grid-connected double-fed induction generator(DFIG)in an oscillating water column power plant(OWCPP).This study presents a novel optimization technique called the circu... This paper validates the optimal operation for a grid-connected double-fed induction generator(DFIG)in an oscillating water column power plant(OWCPP).This study presents a novel optimization technique called the circulatory system-based optimization(CSBO)approach to develop six adaptive fuzzy logic controllers(AFLCs)with 30 parameters and compare them to chaotic-billiards optimization(C-BO)and genetic algorithm(GA).The proposed controller is also compared with a proportional-integral differential(PID)controller based on a self-adaptive global-best harmony search(SGHS).CSBO-based AFLCs are fully investigated under different scenarios and experimented with using a real-time interface DSP1104.The results of using CSBO-AFLCs revealed a fast time response,fast convergence,less overshoot and minimal error compared with those achieved with C-BO-AFLC,SGHS-PID and GA-AFLC during different case studies.The CSBO-based AFLCs ensure maximum power from the DFIG in an OWCPP and enhance dynamic response with very low errors.The results show that the CSBO shows better power tracking by 25%as compared with C-BO,by 45%when compared with the GA and by 56%when compared with PID.Moreover,the integral absolute errors of six controllers are investigated to demonstrate the feasibility of CSBO-AFLC.The root mean square of the errors of six controllers using CSBO is improved by 68.27%when compared with GA,by 22.57%when compared with C-BO and by 38.42%when compared with PID.These indicators demonstrate the feasibility of CSBO when compared with other algorithms with the same OWCPP. 展开更多
关键词 circulatory system-based optimization approach adaptive fuzzy logic controller grid-tied oscillating water column power plant maximum power point tracking
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Prediction of regular wave loads on a fixed offshore oscillating water column-wave energy converter using CFD 被引量:6
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作者 Ahmed Elhanafi 《Journal of Ocean Engineering and Science》 SCIE 2016年第4期268-283,共16页
In this paper,hydrodynamic wave loads on an offshore stationary-floating oscillating water column(OWC)are investigated via a 2D and 3D computational fluid dynamics(CFD)modeling based on the RANS equations and the VOF ... In this paper,hydrodynamic wave loads on an offshore stationary-floating oscillating water column(OWC)are investigated via a 2D and 3D computational fluid dynamics(CFD)modeling based on the RANS equations and the VOF surface capturing scheme.The CFD model is validated against previous experiments for nonlinear regular wave interactions with a surface-piercing stationary barge.Following the validation stage,the numerical model is modified to consider the pneumatic damping effect,and an extensive campaign of numerical tests is carried out to study the wave-OWC interactions for different wave periods,wave heights and pneumatic damping factors.It is found that the horizontal wave force is usually larger than the vertical one.Also,there a direct relationship between the pneumatic and hydrodynamic vertical forces with a maximum vertical force almost at the device natural frequency,whereas the pneumatic damping has a little effect on the horizontal force.Additionally,simulating the turbine damping with an orifice plate induces higher vertical loads than utilizing a slot opening.Furthermore,3D modeling significantly escalates and declines the predicted hydrodynamic vertical and horizontal wave loads,respectively. 展开更多
关键词 Offshore oscillating water column OWC Hydrodynamic wave loads Numerical wave tank CFD 3D effects
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Performance studies on an oscillating water column employing a Savonius rotor 被引量:2
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作者 Sandeep K PATEL Krishnil RAM +1 位作者 M.Rafiuddin AHMED Young-Ho LEE 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第7期1674-1679,共6页
A new oscillating water column (OWC) design is proposed in this study to incorporate a simpler Savonius type turbine. Conventional OWC devices employ a bi-directional turbine such as a Wells or an Impulse turbine to e... A new oscillating water column (OWC) design is proposed in this study to incorporate a simpler Savonius type turbine. Conventional OWC devices employ a bi-directional turbine such as a Wells or an Impulse turbine to extract energy from the air. The disadvantages of the Wells turbine include its inability to self start and stalling. The Savonius turbine is much cheaper and is an effective option at low Reynolds numbers. In the current rectangular OWC device, unlike the circular OWC, the width of entry of the capture chamber can be increased without being influenced by the diameter at the turbine section. To improve its primary capture efficiency, the front and rear walls of the OWC are inclined to minimize reflection. The Savonius rotor characteristics are studied with respect to the change in frequency of the incoming waves. The rotor rpm is sensitive to wave period and primary conversion efficiency while changes in depth only affect the rotor rpm at lower frequencies. The Savonius rotor shows promising results and can be incorporated into large scale OWC devices to reduce costs of the turbine component of the system. 展开更多
关键词 wave energy Savonius rotor oscillating water column inclined chamber
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Hydrodynamic Performance of An Integrated System of Breakwater and A Multi-Chamber OWC Wave Energy Converter
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作者 NING De-zhi ZHANG Xiang-yu +1 位作者 WANG Rong-quan ZHAO Ming 《China Ocean Engineering》 SCIE EI CSCD 2024年第4期543-556,共14页
A multi-chamber oscillating water column wave energy converter(OWC-WEC)integrated to a breakwater is investigated.The hydrodynamic characteristics of the device are analyzed using an analytical model based on the line... A multi-chamber oscillating water column wave energy converter(OWC-WEC)integrated to a breakwater is investigated.The hydrodynamic characteristics of the device are analyzed using an analytical model based on the linear potential flow theory.A pneumatic model is employed to investigate the relationship between the air mass flux in the chamber and the turbine characteristics.The effects of chamber width,wall draft and wall thickness on the hydrodynamic performance of a dual-chamber OWC-WEC are investigated.The results demonstrate that the device,with a smaller front wall draft and a wider rear chamber exhibits a broader effective frequency bandwidth.The device with a chamber-width-ratio of 1:3 performs better in terms of power absorption.Additionally,results from the analysis of a triplechamber OWC-WEC demonstrate that reducing the front chamber width and increasing the rearward chamber width can improve the total performance of the device.Increasing the number of chambers from 1 to 2 or 3 can widen the effective frequency bandwidth. 展开更多
关键词 oscillating water column power extraction efficiency potential flow theory wave energy converter multi-chamber
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Design and Experimental Study of A Pile-Based Breakwater Integrated with OWC Chamber 被引量:1
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作者 QU Ming YU Ding-yong +1 位作者 DOU Zhi-hao WANG Shi-lin 《China Ocean Engineering》 SCIE EI CSCD 2021年第3期443-453,共11页
A structure scheme of a pile-based breakwater with integrated oscillating water column(OWC)energy conversion chamber was proposed,and four structure forms had been designed.Based on the physical test,the variations of... A structure scheme of a pile-based breakwater with integrated oscillating water column(OWC)energy conversion chamber was proposed,and four structure forms had been designed.Based on the physical test,the variations of the reflected wave height,the transmitted wave height,the air velocity at the outlet of the chamber,the air pressure and the wave height in the air chamber were studied under the conditions of different wave heights,periods,with or without elliptical front wall and the baffles on both sides of the chamber.Moreover,based on the results,the changes and relationship between the wave-eliminating effect and energy conversion effect of the scheme were analyzed.In general,it turns out,the transmission coefficients of the four structure forms are kept below 0.5.Furthermore,the transmission coefficients of the structural forms G2,G3,and G4 were all smaller than 0.4,and it is only 0.1 at its smallest.Thereinto,in general,the structure form G4 has the best wave-eliminating and energy conversion performance.At the same time,when the wave steepness is 0.066,the energy conversion and wave dissipation effect of the four structure forms is the best.The research results could be provided as the reference for the design structure selection of pile-based breakwater with integrated OWC energy conversion chamber. 展开更多
关键词 wave energy conversion BREAKwaterS energy efficiency power transmission pile-based breakwaters oscillating water column
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Hydrodynamic Performance of A Dual-Floater Integrated System Com-bining Hybrid WECs and Floating Breakwaters
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作者 FU Lei CHENG Yong 《China Ocean Engineering》 SCIE EI CSCD 2022年第6期969-979,共11页
The high investment and low return of wave energy converters(WECs)seriously hamper their large-scale commercial application.The integration of WECs and floating breakwaters is conducive to enhance the competitiveness ... The high investment and low return of wave energy converters(WECs)seriously hamper their large-scale commercial application.The integration of WECs and floating breakwaters is conducive to enhance the competitiveness of wave energy conversion.The objective of this paper is to investigate the hydrodynamic performance of a WEC-breakwater integrated system combining an upstream oscillating water column(OWC)and a downstream oscillating buoy(OB)via numerical simulations and physical experiments.A nonlinear numerical wave flume using Star-CCM+software is employed to obtain calculated results,where a tiny transverse gap is set between the flume wall and the block surface to simulate a similar two-dimensional(2D)model.The corresponding physical experiments are also carried out in a practical wave flume to verified the numerical results.The comparison of the isolated and hybrid system shows that the hybrid design leads to the decreased conversion efficiency of each WEC,but improves the transmission performance of the hybrid system.The wave resonance between two devices causes the abrupt reduction of OWC efficiency and a positive correlation exists with the OB efficiency.The total efficiency of the hybrid system is raised by an optimal opening ratio,a shallow OWC draft and a short spacing distance.Except for the OWC draft,other design parameters have weak effect on the wave attenuation of the hybrid system.This paper can help understand hydrodynamics of the hybrid WECs integrated with breakwaters and improve their performances. 展开更多
关键词 wave energy converters floating breakwater oscillating buoy oscillating water column numerical wave flume physical experiment
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Design and Construction of GreenWAVE Energy Converter for Shallow Waters off South Australia
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作者 Leigh D. Appleyard 《Journal of Civil Engineering and Architecture》 2015年第10期1179-1184,共6页
Compared with more well-known renewable energy sources, such as wind and solar, the wave energy industry is relatively new. This paper describes the structural design and construction of the oscillating water column ... Compared with more well-known renewable energy sources, such as wind and solar, the wave energy industry is relatively new. This paper describes the structural design and construction of the oscillating water column "greenWAVE Energy Converter" which was constructed during 2013 and was planned to be deployed in shallow water off the South Australian coast in 2014. Rated initially at 1 MW, the greenWAVE unit will be dedicated to electricity production, although an option is available to produce desalinated seawater. The unit base is constructed from reinforced concrete designed to international maritime codes, and the unit will be founded in approximately 10-15 m of water. The upper portion of the device extends above sea level, housing the airwave turbine and electrical control systems. 展开更多
关键词 Wave energy oscillating water column design wave.
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超大浮体与OWC集成系统的水动力性能:半解析研究
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作者 周加春 赵玄烈 +2 位作者 臧军 耿敬 邝庆文 《哈尔滨工程大学学报(英文版)》 CSCD 2023年第2期232-246,共15页
Responses of the very large floating Structures(VLFS)can be mitigated by implementing oscillating water columns(OWCs).This paper explores the fundamental mechanism of present wave interactions with both structures and... Responses of the very large floating Structures(VLFS)can be mitigated by implementing oscillating water columns(OWCs).This paper explores the fundamental mechanism of present wave interactions with both structures and examines the hydrodynamic performance of VLFS equipped with OWCs(VLFS-OWCs).Under the linear potential flow theory framework,the semi-analytical model of wave interaction with VLFS-OWCs is developed using the eigenfunction matching method.The semi-analytical model is verified using the Haskind relationship and wave energy conservation law.Results show that the system with dual-chamber OWCs has a wider frequency bandwidth in wave power extraction and hydroelastic response mitigation of VLFS.It is worth noting that the presence of Bragg resonance can be trigged due to wave interaction with the chamber walls and the VLFS,which is not beneficial for the wave power extraction performance and the protection of VLFS. 展开更多
关键词 Semi-analytical investigation Very large floating structures oscillating water column Bragg resonance Hydroelastic response
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Experimental Study on Conversion Characteristics of Dual-Mode OWC Models Appropriate for Voyaging
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作者 WU Bi-jun ZHANG Fu-ming +2 位作者 QIN Zi-zhen WU Heng-yu RAO Xiang 《China Ocean Engineering》 SCIE EI CSCD 2023年第2期247-257,共11页
Freely movable wave energy converters(WECs) will greatly improve their adaptability to the marine environment.In this paper, a dual-mode oscillating water column(OWC) WEC with potential sailing capability is proposed.... Freely movable wave energy converters(WECs) will greatly improve their adaptability to the marine environment.In this paper, a dual-mode oscillating water column(OWC) WEC with potential sailing capability is proposed. By opening and closing a gate on the side facing the waves, the WEC converts wave energy in the vertical duct(called VD mode) with low sailing resistance or in the backward bend duct(called BBD mode) with high sailing resistance.A small model and a medium model were designed and manufactured. The capture width ratio(CWR) of the small model in the two modes was experimentally studied. The CWR under bidirectional airflow and conversion characteristics under unidirectional airflow of the medium model in the BBD mode were obtained. Tests of the small model show that the peak CWR is 145.2% under regular waves and 90.1% under random waves in BBD mode, and in VD mode the peak CWR is about 60% of that in the BBD mode. Tests of the medium model show that the peak CWR is 228.96% under regular waves, the maximum wave-to-battery efficiency is 63.36% under regular waves and 30.17%under random waves, respectively. 展开更多
关键词 wave energy oscillating water column(OWC) capture width ratio(CWR) wave-to-battery conversion efficiency
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Radiation and Exciting Forces of Axisymmetric Structures with a Moonpool in Waves 被引量:1
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作者 Ronald W.Yeung Lu Wang 《Journal of Marine Science and Application》 CSCD 2018年第3期297-311,共15页
A highly efficient "hybrid integral-equation method" for computing hydrodynamic added-mass, wave-damping, and wave-exciting force of general body geometries with a vertical axis of symmetry is presented. The... A highly efficient "hybrid integral-equation method" for computing hydrodynamic added-mass, wave-damping, and wave-exciting force of general body geometries with a vertical axis of symmetry is presented. The hybrid method utilizes a numerical inner domain and a semi-infinite analytical outer domain separated by a vertical cylindrical matching boundary.Eigenfunction representation of velocity potential is used in the outer domain;the three-dimensional potential in the inner domain is solved using a "two-dimensional" boundary element method with ring sources and ring dipoles to exploit the body symmetry for efficiency. With proper solution matching at the common boundary, both radiation and diffraction potentials can be solved efficiently while satisfying the far-field radiation condition exactly. This method is applied to compute the hydrodynamic properties of two different body geometries: a vertical-walled moonpool with a bottom plate that restricts the opening and a spar-like structure with a diverging bottom opening inspired by designs of floating Oscillating Water Columns. The effects of the size of the bottom opening on the hydrodynamic properties of the body are investigated for both geometries. The heave motion of the floater as well as the motion of the internal free surface under incident wave excitation are computed and studied for the spar-like structure. 展开更多
关键词 Moonpool Spar oscillating water column Potential flow Hybrid method Axisymmetric body
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Effects of Rotor Solidity on the Performance of Impulse Turbine for OWC Wave Energy Converter 被引量:4
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作者 刘臻 赵环宇 崔莹 《China Ocean Engineering》 SCIE EI CSCD 2015年第5期663-672,共10页
Impulse turbine, working as a typical self-rectifying turbine, is recently utilized for the oscillating water column(OWC) wave energy converters, which can rotate in the same direction under the bi-directional air f... Impulse turbine, working as a typical self-rectifying turbine, is recently utilized for the oscillating water column(OWC) wave energy converters, which can rotate in the same direction under the bi-directional air flows. A numerical model established in Fluent is validated by the corresponding experimental results. The flow fields, pressure distribution and dimensionless evaluating coefficients can be calculated and analyzed. Effects of the rotor solidity varying with the change of blade number are investigated and the suitable solidity value is recommended for different flow coefficients. 展开更多
关键词 wave energy oscillating water column impulse turbine rotor solidity operating performance numerical simulation
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Model Test and Design of the Wave Energy System on "Central Fairway No. 1" Light Ship 被引量:1
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作者 Gao Xiangfan , Liang Xianguang Jiang Niandong Feng Manzhi Wang Wei Senior Engineer, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, 510070 GuangzhouAssociate Professor, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, 510070 Guangzhou Engineer, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, 510070 Guangzhou 《China Ocean Engineering》 SCIE EI 1992年第3期351-360,共10页
This paper presents the test of a ship model for the design of a backward-bent duct oscillating water column type wave energy conversion system, to supply electric power for a light ship. This system suggests a new wa... This paper presents the test of a ship model for the design of a backward-bent duct oscillating water column type wave energy conversion system, to supply electric power for a light ship. This system suggests a new way to produce electric power automatically for large light ships. 展开更多
关键词 model test wave energy oscillating water column (OWC) light ship wave-activated generator
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A RANS-VoF Numerical Model to Analyze the Output Power of An OWC-WEC Equipped with Wells and Impulse Turbines in A Hypothetical Sea-State
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作者 Paulo R.F.Teixeira Rafael A.A.C.Gonçalves Eric Didier 《China Ocean Engineering》 SCIE EI CSCD 2020年第6期760-771,共12页
Wave energy is a renewable source with significant amount in relation to the global demand. A good concept of a device applied to extract this type of energy is the onshore oscillating water column wave energy convert... Wave energy is a renewable source with significant amount in relation to the global demand. A good concept of a device applied to extract this type of energy is the onshore oscillating water column wave energy converter(OWC-WEC). This study shows a numerical analysis of the diameter determination of two types of turbines, Wells and Impulse, installed in an onshore OWC device subjected to a hypothetical sea state. Commercial software FLUENT?,which is based on RANS-VoF(Reynolds-Averaged Navier-Stokes equations and Volume of Fluid technique), is employed. A methodology that imposes air pressure on the chamber, considering the air compressibility effect, is used. The mathematical domain consists of a 10 m deep flume with a 10 m long and 10 m wide OWC chamber at its end(geometry is similar to that of the Pico's plant installed in Azores islands, Portugal). On the top of the chamber, a turbine works with air exhalation and inhalation induced by the water free surface which oscillates due to the incident wave. The hypothetical sea state, represented by a group of regular waves with periods from 6 to 12 s and heights from 1.00 to 2.00 m(each wave with an occurrence frequency), is considered to show the potential of the presented methodology. Maximum efficiency(relation between the average output and incident wave powers) of46% was obtained by using a Wells turbine with the diameter of 2.25 m, whereas the efficiency was 44% by an Impulse turbine with the diameter of 1.70 m. 展开更多
关键词 wave energy oscillating water column Wells turbine Impulse turbine RANS-VoF compressible air
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Effect of partial blockage of air duct outlet on performance of OWC device
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作者 S.Patel K.Ram M.Rafiuddin Ahmed 《Journal of Central South University》 SCIE EI CAS 2012年第3期748-754,共7页
The use of a Savonius rotor as turbine for an oscillating water column(OWC) is demonstrated.The effect of tuning the OWC using turbine duct blockage is also studied for different wave conditions.A horizontal turbine s... The use of a Savonius rotor as turbine for an oscillating water column(OWC) is demonstrated.The effect of tuning the OWC using turbine duct blockage is also studied for different wave conditions.A horizontal turbine section OWC employing a Savonius rotor was tested by varying the opening of OWC exit(0%,25%,50%,75% and 100%) to study the behavior and performance of the device.The OWC model was tested at water depth of 0.29 m at frequencies of 0.8,0.9 and 1.0 Hz while the exit openings are varied.The static pressure,dynamic pressure,rotational speed of the Savonius rotor and the coefficient of power are presented as results.The OWC with exit opening of 25% showed greater performance in terms of rotational speed and CP compared to OWC with other exit opening percentages.This proves the ability of the OWC to be tuned by regulating flow in the turbine duct. 展开更多
关键词 oscillating water column wave energy converter wells turbine impulse turbine Savonius rotor
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Experimental Investigation of the Small-scale Fixed Multi-chamber OWC Device
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作者 Mohammad Shalby Ahmed Elhanafi +4 位作者 Paul Walker David G.Dorrell Ahmad Salah Mohamed R.Gomaa Mohamed Behiri 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2021年第5期408-421,共14页
Sea wave energy generators or converters(WECs)have the potential to become a viable technology for clean,renewable energy production.Among the WEC technologies,the oscillating water columns(OWCs)are the most common WE... Sea wave energy generators or converters(WECs)have the potential to become a viable technology for clean,renewable energy production.Among the WEC technologies,the oscillating water columns(OWCs)are the most common WEC devices studied.These have been studied and developed over many years.Multi-chamber oscillating water columns(MC-OWC)have the potential to have a higher energy conversion when extracting energy in mixed sea states than single-chamber devices.In the work reported in this paper,physical experiments are carried under regular wave conditions to test the wave power extraction of a fixed MC-OWC small-scale model.The Power Take-Off(PTO)of the device is simulated using orifice plates.The flow characteristics through these orifices are pre-calibrated such that the extracted power can be obtained only using the pressure measurement.Wave condition effects on the damping of the PTO of the device power extraction are addressed.The test results illustrate that the PTO system damping is critical and affects device performance. 展开更多
关键词 cean wave energy Energy conversion oscillating water column Multi-chamber OWC
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