Journal articles: 'Multi-mode wave energy converter'

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Neshat, Mehdi, Nataliia Sergiienko, Seyedali Mirjalili, Meysam Majidi Nezhad, Giuseppe Piras, and Davide Astiaso Garcia. "Multi-Mode Wave Energy Converter Design Optimisation Using an Improved Moth Flame Optimisation Algorithm." Energies 14, no. 13 (June 22, 2021): 3737. http://dx.doi.org/10.3390/en14133737.

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Ocean renewable wave power is one of the more encouraging inexhaustible energy sources, with the potential to be exploited for nearly 337 GW worldwide. However, compared with other sources of renewables, wave energy technologies have not been fully developed, and the produced energy price is not as competitive as that of wind or solar renewable technologies. In order to commercialise ocean wave technologies, a wide range of optimisation methodologies have been proposed in the last decade. However, evaluations and comparisons of the performance of state-of-the-art bio-inspired optimisation algorithms have not been contemplated for wave energy converters’ optimisation. In this work, we conduct a comprehensive investigation, evaluation and comparison of the optimisation of the geometry, tether angles and power take-off (PTO) settings of a wave energy converter (WEC) using bio-inspired swarm-evolutionary optimisation algorithms based on a sample wave regime at a site in the Mediterranean Sea, in the west of Sicily, Italy. An improved version of a recent optimisation algorithm, called the Moth–Flame Optimiser (MFO), is also proposed for this application area. The results demonstrated that the proposed MFO can outperform other optimisation methods in maximising the total power harnessed from a WEC.

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Demonte Gonzalez, Tania, Gordon G. Parker, Enrico Anderlini, and Wayne W. Weaver. "Sliding Mode Control of a Nonlinear Wave Energy Converter Model." Journal of Marine Science and Engineering 9, no. 9 (September 1, 2021): 951. http://dx.doi.org/10.3390/jmse9090951.

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The most accurate wave energy converter models for heaving point absorbers include nonlinearities, which increase as resonance is achieved to maximize the energy capture. Over the power production spectrum and within the physical limits of the devices, the efficiency of wave energy converters can be enhanced by employing a control scheme that accounts for these nonlinearities. This paper proposes a sliding mode control for a heaving point absorber that includes the nonlinear effects of the dynamic and static Froude-Krylov forces. The sliding mode controller tracks a reference velocity that matches the phase of the excitation force to ensure higher energy absorption. This control algorithm is tested in regular linear waves and is compared to a complex-conjugate control and a nonlinear variation of the complex-conjugate control. The results show that the sliding mode control successfully tracks the reference and keeps the device displacement bounded while absorbing more energy than the other control strategies. Furthermore, due to the robustness of the control law, it can also accommodate disturbances and uncertainties in the dynamic model of the wave energy converter.

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Elgammal, Adel, and Curtis Boodoo. "Optimal Sliding Mode Control of Permanent Magnet Direct Drive Linear Generator for Grid-Connected Wave Energy Conversion." European Journal of Engineering and Technology Research 6, no. 2 (February 8, 2021): 50–57. http://dx.doi.org/10.24018/ejers.2021.6.2.2362.

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the key goal of this article is on the design and optimum sliding mode control for Grid-Connected direct drive extraction method of ocean wave energy by Multi-Objective Particle Swarm Optimization (MOPSO). A Linear Permanent Magnet Generator simulates the ocean wave energy extraction system, driven by an Archimedes Wave Swing. Uncontrolled three-phase rectifiers, a three-level buck-boost converter and 3 level neutral point clamped inverter are planned grid integration of Wave Energy Conversion device. The technique monitors the three-level buck-boost converter service cycle linked to the PMLG output terminals and decides the optimum switching sequence of 3 level neutral point clamped inverter to enable the grid relation. Simulations using Matlab/Simulink were carried out to test working of the wave energy converter after the suggested optimal control method was applied under various operating settings. Various simulation test results indicate that the proposed optimum control system is tested in both normal and irregular ocean waves. And it has been shown that the control method of the MOPSO sliding mode is ideal for maximizing energy transfer efficiency. Better voltage management at the DC-link and for achieving greater controllability spectrum was accomplished by the proposed Duty-ratio optimal control system.

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Elgammal, Adel, and Curtis Boodoo. "Optimal Sliding Mode Control of Permanent Magnet Direct Drive Linear Generator for Grid-Connected Wave Energy Conversion." European Journal of Engineering and Technology Research 6, no. 2 (February 8, 2021): 50–57. http://dx.doi.org/10.24018/ejeng.2021.6.2.2362.

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the key goal of this article is on the design and optimum sliding mode control for Grid-Connected direct drive extraction method of ocean wave energy by Multi-Objective Particle Swarm Optimization (MOPSO). A Linear Permanent Magnet Generator simulates the ocean wave energy extraction system, driven by an Archimedes Wave Swing. Uncontrolled three-phase rectifiers, a three-level buck-boost converter and 3 level neutral point clamped inverter are planned grid integration of Wave Energy Conversion device. The technique monitors the three-level buck-boost converter service cycle linked to the PMLG output terminals and decides the optimum switching sequence of 3 level neutral point clamped inverter to enable the grid relation. Simulations using Matlab/Simulink were carried out to test working of the wave energy converter after the suggested optimal control method was applied under various operating settings. Various simulation test results indicate that the proposed optimum control system is tested in both normal and irregular ocean waves. And it has been shown that the control method of the MOPSO sliding mode is ideal for maximizing energy transfer efficiency. Better voltage management at the DC-link and for achieving greater controllability spectrum was accomplished by the proposed Duty-ratio optimal control system.

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Sarkar, Soumyendu, Vineet Gundecha, Alexander Shmakov, Sahand Ghorbanpour, Ashwin Ramesh Babu, Paolo Faraboschi, Mathieu Cocho, Alexandre Pichard, and Jonathan Fievez. "Multi-Agent Reinforcement Learning Controller to Maximize Energy Efficiency for Multi-Generator Industrial Wave Energy Converter." Proceedings of the AAAI Conference on Artificial Intelligence 36, no. 11 (June 28, 2022): 12135–44. http://dx.doi.org/10.1609/aaai.v36i11.21473.

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Waves in the oceans are one of the most significant renewable energy sources and are an excellent resource to tackle climate challenges through decarbonizing energy generation. Lowering the Levelized Cost of Energy (LCOE) for energy generation from ocean waves is critical for competitiveness with other forms of clean energy like wind and solar. It requires complex controllers to maximize efficiency for state-of-the-art multi-generator industrial Wave Energy Converters (WEC), which optimizes the reactive forces of the generators on multiple legs of WEC. This paper introduces Multi-Agent Reinforcement Learning controller (MARL) architectures that can handle these various objectives for LCOE. MARL can help increase energy capture efficiency to boost revenue, reduce structural stress to limit maintenance cost, and adaptively and proactively protect the wave energy converter from catastrophic weather events preserving investments and lowering effective capital cost. These architectures include 2-agent and 3-agent MARL implementing proximal policy optimization (PPO) with various optimizations to help sustain the training convergence in the complex hyperplane without falling off the cliff. Also, the design for trust assures the operation of WEC within a safe zone of mechanical compliance. As a part of this design, reward shaping for multiple objectives of energy capture and penalty for harmful motions minimizes stress and lowers the cost of maintenance. We achieved double-digit gains in energy capture efficiency across the waves of different principal frequencies over the baseline Spring Damper controller with the proposed MARL controllers.

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Xue, Gang, Jian Qin, Zhenquan Zhang, Shuting Huang, and Yanjun Liu. "Experimental Investigation of Mooring Performance and Energy-Harvesting Performance of Eccentric Rotor Wave Energy Converter." Journal of Marine Science and Engineering 10, no. 11 (November 18, 2022): 1774. http://dx.doi.org/10.3390/jmse10111774.

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To obtain the optimal mooring mode and the best-matching wave condition of an eccentric rotor wave energy converter (ERWEC), a physical model of the ERWEC was developed. Ten mooring modes and eight wave conditions were set up. Several experiments were carried out to analyze the influence of mooring modes and wave conditions on the mooring and energy-harvesting performances of the ERWEC. The results showed that the mooring and energy-harvesting performances changed significantly for the same mooring mode under various regular wave conditions, but the opposite situation was found under irregular wave conditions. The wave-facing direction of the buoy was a critical factor affecting the mooring and energy-harvesting performances, while the number of anchor lines had little effect on them. In addition, a method to evaluate the motion response of the buoy based on the number of effective excitations and a method to evaluate the comprehensive performance based on the cloud chart are proposed. The mooring mode and wave condition combination that obtained the optimal mooring and energy-harvesting performances for the ERWEC was determined. This paper provides a novel perspective on how to balance the efficiency and reliability of wave energy converters.

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Neshat, Mehdi, Nataliia Y. Sergiienko, Erfan Amini, Meysam Majidi Nezhad, Davide Astiaso Garcia, Bradley Alexander, and Markus Wagner. "A New Bi-Level Optimisation Framework for Optimising a Multi-Mode Wave Energy Converter Design: A Case Study for the Marettimo Island, Mediterranean Sea." Energies 13, no. 20 (October 20, 2020): 5498. http://dx.doi.org/10.3390/en13205498.

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To advance commercialisation of ocean wave energy and for the technology to become competitive with other sources of renewable energy, the cost of wave energy harvesting should be significantly reduced. The Mediterranean Sea is a region with a relatively low wave energy potential, but due to the absence of extreme waves, can be considered at the initial stage of the prototype development as a proof of concept. In this study, we focus on the optimisation of a multi-mode wave energy converter inspired by the CETO system to be tested in the west of Sicily, Italy. We develop a computationally efficient spectral-domain model that fully captures the nonlinear dynamics of a wave energy converter (WEC). We consider two different objective functions for the purpose of optimising a WEC: (1) maximise the annual average power output (with no concern for WEC cost), and (2) minimise the levelised cost of energy (LCoE). We develop a new bi-level optimisation framework to simultaneously optimise the WEC geometry, tether angles and power take-off (PTO) parameters. In the upper-level of this bi-level process, all WEC parameters are optimised using a state-of-the-art self-adaptive differential evolution method as a global optimisation technique. At the lower-level, we apply a local downhill search method to optimise the geometry and tether angles settings in two independent steps. We evaluate and compare the performance of the new bi-level optimisation framework with seven well-known evolutionary and swarm optimisation methods using the same computational budget. The simulation results demonstrate that the bi-level method converges faster than other methods to a better configuration in terms of both absorbed power and the levelised cost of energy. The optimisation results confirm that if we focus on minimising the produced energy cost at the given location, the best-found WEC dimension is that of a small WEC with a radius of 5 m and height of 2 m.

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Zhang, Jun, Chenglong Li, Hongzhou He, and Xiaogang Zang. "Optimization of a Multi-pendulum Wave Energy Converter." Open Electrical & Electronic Engineering Journal 9, no. 1 (March 16, 2015): 67–73. http://dx.doi.org/10.2174/1874129001509010067.

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In order to improve the energy capture efficiency of a multi-pendulum wave energy converter, a mathematical model of the pendulum structure has been built. The final structure parameters of the pendulum have been obtained by using genetic algorithm based on the numerical simulation results of the pendulum structure optimization. The results show that under obtained structure parameters the proposed multi-pendulum device can obtain maximum energy conversion efficiency.

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Stansby, Peter, Efrain Carpintero Moreno, Sam Draycott, and Tim Stallard. "Total wave power absorption by a multi-float wave energy converter and a semi-submersible wind platform with a fast far field model for arrays." Journal of Ocean Engineering and Marine Energy 8, no. 1 (October 19, 2021): 43–63. http://dx.doi.org/10.1007/s40722-021-00216-9.

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AbstractWave energy converters absorb wave power by mechanical damping for conversion into electricity and multi-float systems may have high capture widths. The kinetic energy of the floats causes waves to be radiated, generating radiation damping. The total wave power absorbed is thus due to mechanical and radiation damping. A floating offshore wind turbine platform also responds dynamically and damping plates are generally employed on semi-submersible configurations to reduce motion, generating substantial drag which absorbs additional wave power. Total wave power absorption is analysed here by linear wave diffraction–radiation–drag models for a multi-float wave energy converter and an idealised wind turbine platform, with response and mechanical power in the wave energy case compared with wave basin experiments, including some directional spread wave cases, and accelerations compared in the wind platform case. The total power absorption defined by capture width is input into a far field array model with directional wave spreading. Wave power transmission due a typical wind turbine array is only reduced slightly (less than 5% for a 10 × 10 platform array) but may be reduced significantly by rows of wave energy converters (by up to about 50%).

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Chandrasekaran, Srinivasan, and Harender. "Power Generation Using Mechanical Wave Energy Converter." International Journal of Ocean and Climate Systems 3, no. 1 (March 2012): 57–70. http://dx.doi.org/10.1260/1759-3131.3.1.57.

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Ocean wave energy plays a significant role in meeting the growing demand of electric power. Economic, environmental, and technical advantages of wave energy set it apart from other renewable energy resources. Present study describes a newly proposed Mechanical Wave Energy Converter (MEWC) that is employed to harness heave motion of floating buoy to generate power. Focus is on the conceptual development of the device, illustrating details of component level analysis. Employed methodology has many advantages such as i) simple and easy fabrication; ii) easy to control the operations during rough weather; and iii) low failure rate during normal sea conditions. Experimental investigations carried out on the scaled model of MWEC show better performance and its capability to generate power at higher efficiency in regular wave fields. Design Failure Mode and Effect Analysis (FMEA) shows rare failure rates for all components except the floating buoy.

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Díaz, Hugo, José Miguel Rodrigues, and C. Guedes Soares. "New Wave Energy Converter Design Inspired by the Nenuphar Plant." Journal of Marine Science and Engineering 10, no. 11 (November 1, 2022): 1612. http://dx.doi.org/10.3390/jmse10111612.

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This paper presents the Nenuphar concept, an innovative wave energy converter designed to use the kinetic and the potential energy of sea waves, based on the motions of seven modules. First, the main characteristics of the Nenuphar and its work principle are presented. Afterwards, the mathematical formulation of its dynamics is introduced and its validation with a simplified device. A specific MATLAB code was developed to determine the dynamics of hinged, multi-directional bodies. Then, the system’s behaviour was analysed under different wave conditions. The system performance was not strongly dependent on the wave characteristics or the device inclination angle. This initial study confirms the Nenuphar as a potential technology to extract energy from waves.

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Vorob’eva, Elena V., Valery V. Ivakhnik, Darkhan R. Kapizov, and Vladimir I. Nikonov. "Point spread function of a four-wave radiation converter in a multimode waveguide with Kerr nonlinearity." Physics of Wave Processes and Radio Systems 24, no. 1 (May 6, 2021): 15–21. http://dx.doi.org/10.18469/1810-3189.2021.24.1.15-21.

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An expression is obtained for the point spread function of a four-wave radiation converter in a multimode waveguide with Kerr nonlinearity, taking into account the transfer of energy from the object wave to the signal wave and vice versa. For single-mode pump waves, the presence of generation points is shown and conditions are found on the waveguide parameters, characteristics of the interacting waves, under which the generation condition is realized. In the vicinity of the generation points, the shape of the point spread function is determined by one of the waveguide modes, the number of which coincides with the number of the pump wave mode. For a four-wave radiation converter in a waveguide with infinitely conducting surfaces, the quality of the wavefront conjugation near the second generation point coincides with the quality of the wavefront conjugation at a low reflection coefficient. For a four-wave radiation converter in a parabolic waveguide near the second and next generation points, the shape of the point spread function is determined by one of the waveguide modes.

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Garriga-Castillo, Juan A., Hugo Valderrama-Blavi, José A. Barrado-Rodrigo, and Àngel Cid-Pastor. "Analysis of Sliding-Mode Controlled Impedance Matching Circuits for Inductive Harvesting Devices." Energies 12, no. 20 (October 12, 2019): 3858. http://dx.doi.org/10.3390/en12203858.

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A sea-wave energy harvesting, articulated device is presented in this work. This hand-made, wooden device is made combining the coil windings of an array of three single transducers. Taking advantage of the sea waves sway, a linear oscillating motion is produced in each transducer generating an electric pulse. Magnetic fundamentals are used to deduce the electrical model of a single transducer, a solenoid-magnet device, and after the model of the whole harvesting array. The energy obtained is stored in a battery and is used to supply a stand-alone system pay-load, for instance a telecom relay or weather station. To maximize the harvested energy, an impedance matching circuit between the generator array and the system battery is required. Two dc-to-dc converters, a buck-boost hybrid cell and a Sepic converter are proposed as impedance adaptors. To achieve this purpose, sliding mode control laws are introduced to impose a loss free resistor behavior to the converters. Although some converters operating at discontinuous conduction mode, like the buck-boost converter, can exhibit also this loss free resistor behavior, they usually require a small input voltage variation range. By means of sliding mode control the loss free resistor behavior can be assured for any range of input voltage variation. After the theoretical analysis, several simulation and experimental results to compare both converters performance are given.

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Song, Lin Feng, Li Ping Sun, Shang Mao Ai, and Jia Yu Qian. "Constraint Matrix Method Used in Wave Energy Converter." Advanced Materials Research 1030-1032 (September 2014): 497–500. http://dx.doi.org/10.4028/www.scientific.net/amr.1030-1032.497.

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In order to research the motion mechanism of floating multi-bodies, constraint matrix method (CMM) and potential flow theory are used. Compared to the other method, CMM is easier to model and faster in calculating. The Pelamis wave energy converter is modeled by deriving the system to separate rigid bodies. CMM is used to simulate the Pelamis wave energy converter in time domain with code in house by FORTRAN, some important conclusions are got.

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Li, Liang, Xiantao Zhang, Zhiming Yuan, and Yan Gao. "Multi-Stable Mechanism of an Oscillating-Body Wave Energy Converter." IEEE Transactions on Sustainable Energy 11, no. 1 (January 2020): 500–508. http://dx.doi.org/10.1109/tste.2019.2896991.

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Riedl, J. M., T. Van Doorsselaere, and I. C. Santamaria. "Wave modes excited by photospheric p-modes and mode conversion in a multi-loop system." Astronomy & Astrophysics 625 (May 2019): A144. http://dx.doi.org/10.1051/0004-6361/201935393.

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Context. Waves are ubiquitous in the solar corona and there are indications that they are excited by photospheric p-modes. However, it is unclear how p-modes in coronal loops are converted to sausage modes and transverse (kink) modes, which are observed in the corona. Aims. We aim to investigate how those wave modes are excited in the lower corona by photospheric acoustic waves. Methods. We built 3D magnetohydrostatic loop systems with multiple inclinations spanning from the photosphere to the lower corona. We then simulated these atmospheres with the MANCHA code, in which we perturb the equilibrium with a p-mode driver at the bottom of the domain. By splitting the velocity perturbation into components longitudinal, normal, and azimuthal to the magnetic flux surfaces we can study wave behavior. Results. In vertical flux tubes, we find that deformed fast sausage surface waves and slow sausage body waves are excited. In inclined flux tubes fast kink surface waves, slow sausage body waves, and either a fast sausage surface wave or a plane wave are excited. In addition, we calculate a wave conversion factor (0 ≤ C ≤ 1) from acoustic to magnetic wave behavior by taking the ratio of the mean magnetic energy flux to the sum of the mean magnetic and acoustic energy flux and compare it to a commonly used theoretical conversion factor. We find that between magnetic field inclinations of 10° to 30° those two methods lie within 40%. For smaller inclinations the absolute deviation is smaller than 0.1.

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Zhang, Wanchao, Hengxu Liu, Xuewei Zhang, Liang Zhang, and Muhammad Aqeel Ashraf. "Optimal Configurations of Wave Energy Converter Arrays with a Floating Body." Polish Maritime Research 23, s1 (October 1, 2016): 71–77. http://dx.doi.org/10.1515/pomr-2016-0048.

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Abstract An array of floating point-absorbing wave energy converters (WECs) is usually employed for extracting efficiently ocean wave energy. For deep water environment, it is more feasible and convenient to connect the absorbers array with a floating body, such as a semi-submersible bottom-moored disk, whose function is to act as the virtual seabed. In the present work, an array of identical floating symmetrically distributed cylinders in a coaxial moored disk as a wave energy device is proposed The power take-off (PTO) system in the wave energy device is assumed to be composed of a linear/nonlinear damper activated by the buoys heaving motion. Hydrodynamic analysis of the examined floating system is implemented in frequency domain. Hydrodynamic interferences between the oscillating bodies are accounted for in the corresponding coupled equations. The array layouts under the constraint of the disk, incidence wave directions, separating distance between the absorbers and the PTO damping are considered to optimize this kind of WECs. Numerical results with regular waves are presented and discussed for the axisymmetric system utilizing heave mode with these interaction factors, in terms of a specific numbers of cylinders and expected power production.

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Zhang, Dahai, George Aggidis, Yifei Wang, Andy Mccabe, and Wei Li. "Experimental results from wave tank trials of a multi-axis wave energy converter." Applied Physics Letters 103, no. 10 (September 2, 2013): 103901. http://dx.doi.org/10.1063/1.4820435.

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Alamian, Rezvan, Rouzbeh Shafaghat, and Mohammad Reza Safaei. "Multi-Objective Optimization of a Pitch Point Absorber Wave Energy Converter." Water 11, no. 5 (May 9, 2019): 969. http://dx.doi.org/10.3390/w11050969.

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In this paper, a pitch point absorber wave energy converter (WEC) is selected in order to be optimized for the wave characteristics of the Caspian Sea. The optimization process is a multi-objective optimization. For achieving the optimal WEC, mean absorbed power should be maximized while the construction cost should be minimized. The submerged surface area of the WEC is selected as a cost parameter. The amount of mean absorbed power depends on the installation site and also the shape of the WEC. For optimizing the shape of the WEC, various shapes are considered which are categorized into three different sections. A multi-objective genetic algorithm is used for optimization of the model, and the NEMOH software is used to simulate the wave-body interaction. The results show that the bottom flat and upside chamfered geometry with X:Y ratio of 10:1 is the best geometry for the desired application. Comparing the results from the final optimized shape with the optimized basic parallelepipedic hull shape reveals that much more extractable power can be achieved with less cost.

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Stansby, Peter, and Efrain Carpintero Moreno. "Study of Snap Loads for Idealized Mooring Configurations with a Buoy, Inextensible and Elastic Cable Combinations for the Multi-Float M4 Wave Energy Converter." Water 12, no. 10 (October 11, 2020): 2818. http://dx.doi.org/10.3390/w12102818.

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There has been considerable modelling and wave basin validation of the multi-mode, multi-float, moored wave energy converter M4. The 6 float (2 power take off) (PTO) configuration is considered here with mooring from a buoy with light inextensible cables. Large mean mooring forces and very large peak or snap forces were measured in large waves while the rotational response about the hinges (for power take off in operational conditions) was predominantly linear. Modelling has been extended with elastic mooring cables connected directly to the base of the bow float and to the buoy. The experimental mean force is input to the linear diffraction/radiation model. The device response is effectively unchanged. The peak mooring force and tensions remain large with direct connection to the base of the bow float but are only slightly greater than the mean forces with elastic cables to the buoy, and an elastic hawser provides a further slight reduction. For the largest waves measured, the force was about 10% of the dry weight of the platform. The idealized efficient modelling may inform more detailed design while efficient methods for determining highly nonlinear mean forces remain to be established.

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Santo, H., P. H. Taylor, E. Carpintero Moreno, P. Stansby, R. Eatock Taylor, L. Sun, and J. Zang. "Extreme motion and response statistics for survival of the three-float wave energy converter M4 in intermediate water depth." Journal of Fluid Mechanics 813 (January 17, 2017): 175–204. http://dx.doi.org/10.1017/jfm.2016.872.

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This paper presents both linear and nonlinear analyses of extreme responses for a multi-body wave energy converter (WEC) in severe sea states. The WEC known as M4 consists of three cylindrical floats with diameters and draft which increase from bow to stern with the larger mid and stern floats having rounded bases so that the overall system has negligible drag effects. The bow and mid float are rigidly connected by a beam and the stern float is connected by a beam to a hinge above the mid float where the rotational relative motion would be damped to absorb power in operational conditions. A range of focussed wave groups representing extreme waves were tested on a scale model without hinge damping, also representing a more general system of interconnected cylindrical floats with multi-mode forcing. Importantly, the analysis reveals a predominantly linear response structure in hinge angle and weakly nonlinear response for the beam bending moment, while effects due to drift forces, expected to be predominantly second order, are not accounted for. There are also complex and violent free-surface effects on the model during the excitation period driven by the main wave group, which generally reduce the overall motion response. Once the main group has moved away, the decaying response in the free-vibration phase decays at a rate very close to that predicted by simple linear radiation damping. Two types of nonlinear harmonic motion are demonstrated. During the free-vibration phase, there are only double and triple frequency Stokes harmonics of the linear motion, captured using a frequency doubling and tripling model. In contrast, during the excitation phase, these harmonics show much more complex behaviour associated with nonlinear fluid loading. Although bound harmonics are visible in the system response, the overall response is remarkably linear until temporary submergence of the central float (‘dunking’) occurs. This provides a strong stabilising effect for angular amplitudes greater than ${\sim}30^{\circ }$ and can be treated as a temporary loss of part of the driving wave as long as submergence continues. With an experimentally and numerically derived response amplitude operator (RAO), we perform a statistical analysis of extreme response for the hinge angle based on wave data at Orkney, well known for its severe wave climate, using the NORA10 wave hindcast. For storms with spectral peak wave periods longer than the RAO peak period, the response is controlled by the steepness of the sea state rather than the wave height. Thus, the system responds very similarly under the most extreme sea states, providing an upper bound for the most probable maximum response, which is reduced significantly in directionally spread waves. The methodology presented here is relevant to other single and multi-body systems including WECs. We also demonstrate a general and potentially important reciprocity result for linear body motion in random seas: the averaged wave history given an extreme system response and the average response history given an extreme wave match in time, with time reversed for one of the signals. This relationship will provide an efficient and robust way of defining a ‘designer wave’, for both experimental testing and computationally intensive computational fluid dynamics (CFD), for a wide range of wave–structure interaction problems.

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Kim, Jeong-Rok, Jong-Wu Hyeon, Hyeok-Jun Koh, Hyuck-Min Kweon, and Il-Hyoung Cho. "Model Test of Dual-Buoy Wave Energy Converter using Multi-resonance." Journal of Ocean Engineering and Technology 29, no. 2 (April 30, 2015): 191–98. http://dx.doi.org/10.5574/ksoe.2015.29.2.191.

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Kamranzad, Bahareh, and Sanaz Hadadpour. "A multi-criteria approach for selection of wave energy converter/location." Energy 204 (August 2020): 117924. http://dx.doi.org/10.1016/j.energy.2020.117924.

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Hu, Dong Dong, Yan Jun Liu, Li Kang Hong, and Xiao Chen Guo. "Finite Element Analysis for Water Turbine of Horizontal Axis Rotor Wave Energy Converter." Applied Mechanics and Materials 530-531 (February 2014): 906–10. http://dx.doi.org/10.4028/www.scientific.net/amm.530-531.906.

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Horizontal axis rotor wave energy converter is a new form for utilization of ocean wave energy, and the axis of its water turbine is parallel with the sea level and perpendicular to the direction of wave. This paper employed the linear wave theory and Froude-Krylov presumptive method to calculate the wave force, which was exerted on the wave energy converter in extremely arduous wave conditions. The finite element research on the deformation and the stress response of the water turbine was carried out to assess its security. The results show that the deformation and the stress responses both reach their maximum values at the 3rd mode shape about 90Hz, and the deformation response is 0.4208mm and the stress response is 0.8052MPa at this frequency, which are both within the required security range.

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Sun, L., P. Stansby, J. Zang, E. Carpintero Moreno, and P. H. Taylor. "Linear diffraction analysis for optimisation of the three-float multi-mode wave energy converter M4 in regular waves including small arrays." Journal of Ocean Engineering and Marine Energy 2, no. 4 (June 17, 2016): 429–38. http://dx.doi.org/10.1007/s40722-016-0059-1.

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Hadano, Kesayoshi, Ki Yeol Lee, and Byung Young Moon. "A study on dynamic motion and wave power in multi-connected wave energy converter." Ships and Offshore Structures 11, no. 7 (March 21, 2016): 679–87. http://dx.doi.org/10.1080/17445302.2015.1045269.

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Zhang, Dahai, Aggidis George, Yifei Wang, Xinxing Gu, Wei Li, and Ying Chen. "Wave tank experiments on the power capture of a multi-axis wave energy converter." Journal of Marine Science and Technology 20, no. 3 (February 11, 2015): 520–29. http://dx.doi.org/10.1007/s00773-015-0306-5.

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Jabrali, A., R. Khatyr, and J. Khalid Naciri. "Parameters variation effects on energy recovery for a freely floating wave energy converter." MATEC Web of Conferences 286 (2019): 09002. http://dx.doi.org/10.1051/matecconf/201928609002.

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This study presents the effects of parameters variations on the recovered energy for a floating wave energy converter (WEC) device. The articulated multi body floating WEC under consideration consists of two cylinders connected by a flat plate. The connections between the parts of the WEC allow the rotational movements of cylinders and the plate. The aim of this paper is to investigate the coupled effect of the length of the plate with the amplitude and period of the wave on the recovered energy by the floating WEC. The results show that the value of the optimum length for the plate is related to the sea wave condition, and more particularly to the amplitude and wavelength of the oscillations of the free surface.

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Tay, Zhi Yung, and Vengatesan Venugopal. "The impact of energy extraction of wave energy converter arrays on wave climate under multi-directional seas." Journal of Ocean Engineering and Marine Energy 5, no. 1 (January 24, 2019): 51–72. http://dx.doi.org/10.1007/s40722-019-00127-w.

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Orszaghova, J., H. Wolgamot, S. Draper, R. Eatock Taylor, P. H. Taylor, and and A. Rafiee. "Transverse motion instability of a submerged moored buoy." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 475, no. 2221 (January 2019): 20180459. http://dx.doi.org/10.1098/rspa.2018.0459.

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Wave energy converters and other offshore structures may exhibit instability, in which one mode of motion is excited parametrically by motion in another. Here, theoretical results for the transverse motion instability (large sway oscillations perpendicular to the incident wave direction) of a submerged wave energy converter buoy are compared to an extensive experimental dataset. The device is axi-symmetric (resembling a truncated vertical cylinder) and is taut-moored via a single tether. The system is approximately a damped elastic pendulum. Assuming linear hydrodynamics, but retaining nonlinear tether geometry, governing equations are derived in six degrees of freedom. The natural frequencies in surge/sway (the pendulum frequency), heave (the springing motion frequency) and pitch/roll are derived from the linearized equations. When terms of second order in the buoy motions are retained, the sway equation can be written as a Mathieu equation. Careful analysis of 80 regular wave tests reveals a good agreement with the predictions of sub-harmonic (period-doubling) sway instability using the Mathieu equation stability diagram. As wave energy converters operate in real seas, a large number of irregular wave runs is also analysed. The measurements broadly agree with a criterion (derived elsewhere) for determining the presence of the instability in irregular waves, which depends on the level of damping and the amount of parametric excitation at twice the natural frequency.

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Yang, Shao-hui, Yong-qing Wang, Hong-zhou He, Jun Zhang, and Hu Chen. "Dynamic Properties and Energy Conversion Efficiency of A Floating Multi-Body Wave Energy Converter." China Ocean Engineering 32, no. 3 (June 2018): 347–57. http://dx.doi.org/10.1007/s13344-018-0036-7.

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Xiao, Lei, Ya-ge You, Zhen-peng Wang, Ya-qun Zhang, Shuo Huang, and Wen-sheng Wang. "Single Mode Simulation Calculation of Oscillating Buoy Wave Energy Converter with A Slider." China Ocean Engineering 34, no. 4 (August 2020): 547–57. http://dx.doi.org/10.1007/s13344-020-0049-x.

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Boccalero, Gregorio, Simon Chesne, Emmanuel Mignot, Nicolas Riviere, and Claire Jean-Mistral. "Experimental investigations of a new concept of wave energy converter hybridizing piezoelectric and dielectric elastomer generators." Smart Materials and Structures 31, no. 1 (November 19, 2021): 015006. http://dx.doi.org/10.1088/1361-665x/ac36af.

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Abstract A novel concept of a surge wave energy converter for nearshore applications is investigated experimentally. The centimetre-sized prototype developed in this work represents a proof of concept of a submerged system, which entails a hybrid transduction solution for the electrical conversion of wave energy, that uses piezoelectric elements (PZEs) and dielectric elastomer generators (DEG). The idea is to exploit the horizontal pressure gradient and horizontal water velocity underneath the waves to compress the PZE and inflate each half wave period a soft variable capacitance, which composes the DEG. The electrical charges created by the PZE are used to polarize the DEG, which is able to multiply the input energy. This hybridization is conceived to allow the system to generate electrical energy from waves without conventional high voltage supplies, thus reducing production costs and allowing standalone clean electrical generation. The article provides the preliminary fluid-mechanical measurements performed in a wave flume with a first version of the prototype and supported by a model comprising the fluid/structure interaction, the materials response, and the electrical operations. An estimation of the output energy of a small-sized prototype in constant charge mode is computed, and perspectives for optimizing the system are presented.

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Do, H. T., M. T. Nguyen, C. B. Phan, S. Y. Lee, H. G. Park, and K. K. Ahn. "Development of a Multi-Absorbing Wave Energy Converter using Pressure Coupling Principle." Journal of The Korean Society for Fluid Power & Construction Equipments 11, no. 3 (September 1, 2014): 31–40. http://dx.doi.org/10.7839/ksfc.2014.11.3.031.

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Mia, Mohammad Rashed, Ming Zhao, Helen Wu, and Heath Palmer. "Numerical simulation of a stationary offshore multi-chamber OWC wave energy converter." Ocean Engineering 265 (December 2022): 112546. http://dx.doi.org/10.1016/j.oceaneng.2022.112546.

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Neary, Vincent S., Seongho Ahn, Bibiana E. Seng, Mohammad Nabi Allahdadi, Taiping Wang, Zhaoqing Yang, and Ruoying He. "Characterization of Extreme Wave Conditions for Wave Energy Converter Design and Project Risk Assessment." Journal of Marine Science and Engineering 8, no. 4 (April 18, 2020): 289. http://dx.doi.org/10.3390/jmse8040289.

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Best practices and international standards for determining n-year return period extreme wave (sea states) conditions allow wave energy converter designers and project developers the option to apply simple univariate or more complex bivariate extreme value analysis methods. The present study compares extreme sea state estimates derived from univariate and bivariate methods and investigates the performance of spectral wave models for predicting extreme sea states at buoy locations within several regional wave climates along the US East and West Coasts. Two common third-generation spectral wave models are evaluated, a WAVEWATCH III® model with a grid resolution of 4 arc-minutes (6–7 km), and a Simulating WAves Nearshore model, with a coastal resolution of 200–300 m. Both models are used to generate multi-year hindcasts, from which extreme sea state statistics used for wave conditions characterization can be derived and compared to those based on in-situ observations at National Data Buoy Center stations. Comparison of results using different univariate and bivariate methods from the same data source indicates reasonable agreement on average. Discrepancies are predominantly random. Large discrepancies are common and increase with return period. There is a systematic underbias for extreme significant wave heights derived from model hindcasts compared to those derived from buoy measurements. This underbias is dependent on model spatial resolution. However, simple linear corrections can effectively compensate for this bias. A similar approach is not possible for correcting model-derived environmental contours, but other methods, e.g., machine learning, should be explored.

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Wang, Zhen Peng, Ya Ge You, Ya Qun Zhang, Song Wei Sheng, and Hong Jun Lin. "Design and Hydrodynamic Performance Testing of One-Base Multi-Buoy Floating Sharp Eagle Wave Energy Converter." Advanced Materials Research 1092-1093 (March 2015): 152–57. http://dx.doi.org/10.4028/www.scientific.net/amr.1092-1093.152.

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Research on wave energy extraction has been conducted in many countries to meet the growing demand for clean energy. To find an efficient and economic way to convert wave energy, an one-base multi-buoy offshore floating Sharp Eagle wave energy converter is designed, consisting of four Eagle head absorbing buoys, one semi-submersible barge, one energy conversion system, buoyancy tanks, underwater appendages and other components. The working principle of the device is described in this paper. To test the hydrodynamic performance of device and make an initial evaluation for the design, a model experiment of 1/13.78th scale was carried out. The influence of wave period, wave height, pressure in hydrocylinders and wave direction is tested. All the efficiencies in different conditions are compared with each other, while the high efficiency and stability of device are verified.

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Liu, Bingqi, Carlos Levi, Segen F. Estefen, Zhijia Wu, and Menglan Duan. "Evaluation of the Double Snap-Through Mechanism on the Wave Energy Converter’s Performance." Journal of Marine Science and Application 20, no. 2 (May 11, 2021): 268–83. http://dx.doi.org/10.1007/s11804-021-00202-5.

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AbstractLower efficiencies induce higher energy costs and pose a barrier to wave energy devices’ commercial applications. Therefore, the efficiency enhancement of wave energy converters has received much attention in recent decades. The reported research presents the double snap-through mechanism applied to a hemispheric point absorber type wave energy converter (WEC) to improve the energy absorption performance. The double snap-through mechanism comprises four oblique springs mounted in an X-configuration. This provides the WEC with different dynamic stability behaviors depending on the particular geometric and physical parameters employed. The efficiency of these different WEC behaviors (linear, bistable, and tristable) was initially evaluated under the action of regular waves. The results for bistable or tristable responses indicated significant improvements in the WEC’s energy capture efficiency. Furthermore, the WEC frequency bandwidth was shown to be significantly enlarged when the tristable mode was in operation. However, the corresponding tristable trajectory showed intra-well behavior in the middle potential well, which induced a more severe low-energy absorption when a small wave amplitude acted on the WEC compared to when the bistable WEC was employed. Nevertheless, positive effects were observed when appropriate initial conditions were imposed. The results also showed that for bistable or tristable responses, a suitable spring stiffness may cause the buoy to oscillate in high energy modes.

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Hu, Yuan, Shaohui Yang, Hongzhou He, and Hu Chen. "Influence of Central Platform on Hydrodynamic Performance of Semi-Submerged Multi-Buoy Wave Energy Converter." Journal of Marine Science and Engineering 8, no. 1 (December 23, 2019): 12. http://dx.doi.org/10.3390/jmse8010012.

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The influence of the central platform on hydrodynamic performance of a wave energy converter (WEC) has remained elusive. To approach this dearth of relevant theoretical research, this paper presents a semi-submerged multi-buoy WEC and the results of the numerical analysis at different dimension parameters of the central platform of the WEC. The WEC consists of three oscillating buoys hinged with a central platform through multiple actuating arms. Numerical analysis revealed that there exists a relationship between the hydrodynamic performance of device and the geometry of the central platform. At the given wave condition, different central platform size would obviously affect the hydrodynamic performance and wave energy capture width ratio of the semi-submerged multi-buoy WEC. Additionally, appropriately increasing central platform draft would help to improve the wave energy capture capability of the oscillating buoys.

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40

Williams, R. G., G. Roberts, and K. Hawkins. "EXTRACTING SUB-SURFACE INFORMATION FROM LONG OFFSET P-WAVE DATA—A CHEAPER ALTERNATIVE TO MULTICOMPONENT OBC FOR EXPLORATION?" APPEA Journal 42, no. 1 (2002): 627. http://dx.doi.org/10.1071/aj01038.

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Seismic energy that has been mode converted from pwave to s-wave in the sub-surface may be recorded by multi-component surveys to obtain information about the elastic properties of the earth. Since the energy converted to s-wave is missing from the p-wave an alternative to recording OBC multi-component data is to examine p-wave data for the missing energy. Since pwave velocities are generally faster than s-wave velocities, then for a given reflection point the converted s-wave signal reaches the surface at a shorter offset than the equivalent p-wave information. Thus, it is necessary to record longer offsets for p-wave data than for multicomponent data in order to measure the same information.A non-linear, wide-angle (including post critical) AVO inversion has been developed that allows relative changes in p-wave velocities, s-wave velocities and density to be extracted from long offset p-wave data. To extract amplitudes at long offsets for this inversion it is necessary to image the data correctly, including correcting for higher order moveout and possibly anisotropy if it is present.The higher order moveout may itself be inverted to yield additional information about the anisotropy of the sub-surface.

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41

Falnes, Johannes, and Jørgen Hals. "Heaving buoys, point absorbers and arrays." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 370, no. 1959 (January 28, 2012): 246–77. http://dx.doi.org/10.1098/rsta.2011.0249.

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Absorption of wave energy may be considered as a phenomenon of interference between incident and radiated waves generated by an oscillating object; a wave-energy converter (WEC) that displaces water. If a WEC is very small in comparison with one wavelength, it is classified as a point absorber (PA); otherwise, as a ‘quasi-point absorber’. The latter may be a dipole-mode radiator, for instance an immersed body oscillating in the surge mode or pitch mode, while a PA is so small that it should preferably be a source-mode radiator, for instance a heaving semi-submerged buoy. The power take-off capacity, the WEC's maximum swept volume and preferably also its full physical volume should be reasonably matched to the wave climate. To discuss this matter, two different upper bounds for absorbed power are applied in a ‘Budal diagram’. It appears that, for a single WEC unit, a power capacity of only about 0.3 MW matches well to a typical offshore wave climate, and the full physical volume has, unfortunately, to be significantly larger than the swept volume, unless phase control is used. An example of a phase-controlled PA is presented. For a sizeable wave-power plant, an array consisting of hundreds, or even thousands, of mass-produced WEC units is required.

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Eskilsson, Claes, Johannes Palm, Pär Johannesson, and Guilherme Moura Paredes. "Sensitivity analysis of extreme loads acting on a point-absorbing wave energy converter." International Marine Energy Journal 5, no. 1 (June 18, 2022): 91–101. http://dx.doi.org/10.36688/imej.5.91-101.

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There are many uncertainties associated with the estimation of extreme loads acting on a wave energy converter (WEC). In this study we perform a sensitivity analysis of extreme loads acting on the Uppsala University (UU) WEC concept. The UU WEC consists of a bottom-mounted linear generator that is connected to a surface buoy with a taut mooring line. The maximum stroke length of the linear generator is enforced by end-stop springs. Initially, a Variation Mode and Effect Analysis (VMEA) was carried out in order to identify the largest input uncertainties. The system was then modelled in the time-domain solver WEC-SIM coupled to the dynamic mooring solver Moody. A sensitivity analysis was made by generating a surrogate model based on polynomial chaos expansions, which rapidly evaluates the maximum loads on the mooring line and the end-stops. The sensitivities are ranked using the Sobol index method. We investigated two sea states using equivalent regular waves (ERW) and irregular wave (IRW) trains. We found that the ERW approach significantly underestimate the maximum loads. Interestingly, the ERW predicted wave height and period as the most important parameters for the maximum mooring tension, whereas the tension in IRW was most sensitive to the drag coefficient of the surface buoy. The end-stop loads were most sensitive to the PTO damping coefficient.

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Sirigu, Sergej Antonello, Ludovico Foglietta, Giuseppe Giorgi, Mauro Bonfanti, Giulia Cervelli, Giovanni Bracco, and Giuliana Mattiazzo. "Techno-Economic Optimisation for a Wave Energy Converter via Genetic Algorithm." Journal of Marine Science and Engineering 8, no. 7 (June 30, 2020): 482. http://dx.doi.org/10.3390/jmse8070482.

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Although sea and ocean waves have been widely acknowledged to have the potential of providing sustainable and renewable energy, the emergence of a self-sufficient and mature industry is still lacking. An essential condition for reaching economic viability is to minimise the cost of electricity, as opposed to simply maximising the converted energy at the early design stages. One of the tools empowering developers to follow such a virtuous design pathway is the techno-economic optimisation. The purpose of this paper is to perform a holistic optimisation of the PeWEC (pendulum wave energy converter), which is a pitching platform converting energy from the oscillation of a pendulum contained in a sealed hull. Optimised parameters comprise shape; dimensions; mass properties and ballast; power take-off control torque and constraints; number and characteristics of the pendulum; and other subcomponents. Cost functions are included and the objective function is the ratio between the delivered power and the capital expenditure. Due to its ability to effectively deal with a large multi-dimensional design space, a genetic algorithm is implemented, with a specific modification to handle unfeasible design candidate and improve convergence. Results show that the device minimising the cost of energy and the one maximising the capture width ratio are substantially different, so the economically-oriented metric should be preferred.

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Belibassakis, Kostas, Markos Bonovas, and Eugen Rusu. "A Novel Method for Estimating Wave Energy Converter Performance in Variable Bathymetry Regions and Applications." Energies 11, no. 8 (August 11, 2018): 2092. http://dx.doi.org/10.3390/en11082092.

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A numerical model is presented for the estimation of Wave Energy Converter (WEC) performance in variable bathymetry regions, taking into account the interaction of the floating units with the bottom topography. The proposed method is based on a coupled-mode model for the propagation of the water waves over the general bottom topography, in combination with a Boundary Element Method for the treatment of the diffraction/radiation problems and the evaluation of the flow details on the local scale of the energy absorbers. An important feature of the present method is that it is free of mild bottom slope assumptions and restrictions and it is able to resolve the 3D wave field all over the water column, in variable bathymetry regions including the interactions of floating bodies of general shape. Numerical results are presented concerning the wave field and the power output of a single device in inhomogeneous environment, focusing on the effect of the shape of the floater. Extensions of the method to treat the WEC arrays in variable bathymetry regions are also presented and discussed.

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45

Hadano, Kesayoshi, Pallav Koirala, and Byung Young Moon. "A Study on Dynamic Motion and Wave Power in Multi-Connected Float-Counterweight Type of Wave Energy Converter." Advanced Materials Research 1125 (October 2015): 566–70. http://dx.doi.org/10.4028/www.scientific.net/amr.1125.566.

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Recently, with respect to structural strength and relevant analysis of a float-counterweight wave energy converter, it has been more improved than existing oscillating body type. this study is mainly focusing on dynamic motion and wave power generation of ‘multi-connected’ float-counterweight device by calculating the acquired generation amount. This advanced research based on the original float-counterweight device was conducted through the wave’s up and down motion by setting up bulkhead which is called wave camber. Most of all, it was obtained that the ‘multi-connected’ float-counterweight device would be more efficient and practical than the original one in terms of float displacement, wire tension and amount of wave power. Through this study, a basic data for design of wave chamber was utilized on advantageous condition under actual circumstances of the sea and then estimation of generation amount for the ‘multi-connected’ float-counterweight device was realized, compared to the original one.

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Christidis, Georgios, Anastasios Nanakos, and Emmanuel Tatakis. "Optimal Design of a Flyback Microinverter Operating under Discontinuous-Boundary Conduction Mode (DBCM)." Energies 14, no. 22 (November 9, 2021): 7480. http://dx.doi.org/10.3390/en14227480.

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The flyback converter has been widely used in Photovoltaic microinverters, operating either in Discontinuous, Boundary, or Continuous Conduction Mode (DCM, BCM, CCM). The recently proposed hybrid DBCM operation inherits the merits of both DCM and BCM. In this work, the necessary analytical equations describing the converter operation for any given condition under DBCM are derived, and are needed due to the hybrid nature of the modulation strategy during each sinusoidal wave. Based on this analysis, a design optimization sequence used to maximize the weighted efficiency of the inverter under DBCM is then applied. The design procedure is based on a power loss analysis for each converter component and focuses on the appropriate selection of the converter parameters. To achieve this, accurate, fully parameterized loss models of the converter components are implemented. The power loss analysis is then validated by applying the optimization methodology to build an experimental prototype operating in DBCM.

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Wang, Zhenchun, Feng Luan, and Nianguo Wang. "An improved model predictive control method for wave energy converter with sliding mode control." Ocean Engineering 240 (November 2021): 109881. http://dx.doi.org/10.1016/j.oceaneng.2021.109881.

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Brando, Gianluca, Luigi Pio Di Noia, Andrea Del Pizzo, Adolfo Dannier, and Cosimo Pisani. "Grid connection of wave energy converter in heaving mode operation by supercapacitor storage technology." IET Renewable Power Generation 10, no. 1 (January 1, 2016): 88–97. http://dx.doi.org/10.1049/iet-rpg.2015.0093.

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Wan, Chang, Can Yang, Qinghe Fang, Zaijin You, Jing Geng, and Yongxue Wang. "Hydrodynamic Investigation of a Dual-Cylindrical OWC Wave Energy Converter Integrated into a Fixed Caisson Breakwater." Energies 13, no. 4 (February 18, 2020): 896. http://dx.doi.org/10.3390/en13040896.

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A fixed dual cylindrical oscillating water column (OWC) acting as a breakwater-type wave energy converter (WEC) is proposed to harvest the wave energy effectively for shallow offshore sites. An analytical model is developed to investigate the hydrodynamic characteristics and the energy capture capacity of the cylindrical OWC device in severe waves. Based on the linear potential flow theory, the analytical solutions of the velocity potential in diffraction mode are solved by matching the Eigen-function expansion technique, and the continuous conditions of the velocity potential and fluid velocity between the computational sub-domains are involved in solving the problem for determining a solution. The proposed model is verified against the published data. The effects of the wave height, the angle of chamber clapboard and the radius of the inner and outer cylindrical column on the energy conversion efficiency are investigated in this paper. To improve the energy conversion performance and obtain a faster prediction for structural optimization of the cylindrical OWC, the geometrical parameters are further discussed in the analytical model. The results indicate that the geometrical parameters of the chamber have significant effects on the wave energy absorption efficiency. It is found that the effective frequency bandwidth of the dual cylindrical column can be broadened by improving the angle of the chamber clapboard and the inner–outer cylinder diameter ratio.

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Jungrungruengtaworn, S., N. Thaweewat, and B. S. Hyun. "Three-dimensional effects on the performance of multi-level overtopping wave energy converter." IOP Conference Series: Materials Science and Engineering 1137, no. 1 (May 1, 2021): 012016. http://dx.doi.org/10.1088/1757-899x/1137/1/012016.

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Journal articles on the topic 'Multi-mode wave energy converter'

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