Experimental Wave Generation and Cancellation With a Cycloidal Wave Energy Converter

2011 ◽  
Author(s):  
Stefan G. Siegel ◽  
Marcus Ro¨mer ◽  
John Imamura ◽  
Casey Fagley ◽  
Thomas McLaughlin
Keyword(s):  
Wave Energy ◽  
Water Waves ◽  
Wave Generation ◽  
Wave Energy Converter ◽  
Design Parameters ◽  
Main Shaft ◽  
Energy Converter ◽  
Incoming Wave ◽  
Wave Flume ◽  
Wave Maker

We investigate a lift based wave energy converter (WEC), namely, a cycloidal turbine, as a wave termination device. A cycloidal turbine employs the same geometry as the well established Cycloidal or Voith-Schneider Propeller. The main shaft is aligned parallel to the wave crests and fully submerged at a fixed depth. We show that the geometry of the Cycloidal WEC is suitable for single sided wave generation as well as wave termination of straight crested waves using feedback control.The cycloidal WEC consists of a shaft and one or more hydrofoils that are attached eccentrically to the main shaft. An experimental investigation into the wave generation capabilities of the WEC are presented in this paper, along with initial wave cancellation results for deep water waves. The experiments are conducted in a small 2D wave flume equipped with a flap type wave maker as well as a 1:4 sloped beach. The operation of the Cycloidal WEC both as a wave generator as well as a wave energy converter interacting with a linear Airy wave is demonstrated. The influence that design parameters radius and submergence depth on the performance of the WEC have is shown. For wave cancellation, the incoming wave is reduced in amplitude by ≈ 80% in these experiments. In this case wave termination efficiencies of up to 95% of the incoming wave energy with neglegible harmonic waves generated are achieved by synchronizing the rotational rate and phase of the Cycloidal WEC to the incoming wave.

Intermediate Ocean Wave Termination Using a Cycloidal Wave Energy Converter

2010 ◽  
Author(s):  
Stefan G. Siegel ◽  
Tiger Jeans ◽  
Thomas McLaughlin
Keyword(s):  
Wave Energy ◽  
Water Waves ◽  
Optimal Parameter ◽  
Wave Energy Converter ◽  
Design Parameters ◽  
Intermediate Water ◽  
Main Shaft ◽  
Energy Converter ◽  
Incoming Wave ◽  
Conversion Efficiencies

We investigate a lift based wave energy converter (WEC), namely, a cycloidal turbine, as a wave termination device. A cycloidal turbine employs the same geometry as the well established Cycloidal or Voith-Schneider Propeller. The interaction of intermediate water waves with the Cycloidal WEC is presented in this paper. The cycloidal WEC consists of a shaft and one or more hydrofoils that are attached eccentrically to the main shaft and can be adjusted in pitch angle as the Cycloidal WEC rotates. The main shaft is aligned parallel to the wave crests and fully submerged at a fixed depth. We show that the geometry of the Cycloidal WEC is suitable for wave termination of straight crested waves. Two-dimensional potential flow simulations are presented where the hydrofoils are modeled as point vortices. The operation of the Cycloidal WEC both as a wave generator as well as a wave energy converter interacting with a linear Airy wave is demonstrated. The influence that the design parameters radius and submergence depth on the performance of the WEC have is shown. For optimal parameter choices, we demonstrate inviscid energy conversion efficiencies of up to 95% of the incoming wave energy to shaft energy. This is achieved by using feedback control to synchronize the rotational rate and phase of the Cycloidal WEC to the incoming wave. While we show complete termination of the incoming wave, the remainder of the energy is lost to harmonic waves travelling in the upwave and downwave direction.

Stochastic Analysis of a Nonlinear Energy Harvester Model

2014 ◽  
Author(s):  
P. D. Spanos ◽  
A. Richichi ◽  
F. Arena
Keyword(s):  
Dynamic Analysis ◽  
Wave Energy ◽  
Water Waves ◽  
Nonlinear Dynamic Analysis ◽  
Nonlinear Effects ◽  
Wave Energy Converter ◽  
Statistical Linearization ◽  
Energy Converter ◽  
Domain Integration ◽  
Stiffness And Damping

Floating oscillating-bodies are a kind of wave energy converter developed for harvesting the great amount of energy related to water waves (see Falcão [1] for a review). Although the assumptions of small-wave and linear behavior of oscillating system are reasonable for most of the time during which a floating point harvester is in operation, nonlinear effects may be significant in extreme sea states situations. In this paper a nonlinear dynamic analysis of a point harvester wave energy converter is conducted. The model involves a tightly moored single-body floating device; it captures motion in the horizontal and vertical directions. The stiffness and damping forces, being functions of the displacement and velocity components, make the system nonlinear and coupled. For the input forces, the erratic nature of the waves is modeled by a stochastic process. Specifically, wind-generated waves are modeled by means of the JONSWAP spectrum. The method of statistical linearization [2] is used to determine iteratively the effective linear stiffness and damping matrices and response statistics of the system and to proceed to conducting a dynamic analysis of the harvester model. The reliability of the linearization based approach is demonstrated by comparison with time domain integration, Monte Carlo simulation, data. This approach offers the appealing feature of conducting efficiently a variety of parameter studies which can expedite preliminary evaluations, inter alia, of competing design scenarios for the energy converter in a stochastic environmental setting.

Modeling and Experiment of a Novel Micro Wave Energy Converter

2017 ◽  
Vol 863 ◽  
pp. 175-182
Author(s):  
Yi Ming Zhu ◽  
Zi Rong Luo ◽  
Zhong Yue Lu ◽  
Jian Zhong Shang
Keyword(s):  
Output Power ◽  
Wave Energy ◽  
Mechanical Energy ◽  
Vertical Motion ◽  
Electrical Energy ◽  
Wave Energy Converter ◽  
Design Parameters ◽  
Energy Converter ◽  
Drive Power ◽  
Continuous Rotation

This paper proposed a novel micro wave energy converter which can convert irregular wave energy into rotating mechanical energy, then into electrical energy. The device consists of an energy absorption part and an energy conversion part. In details, the blades are installed on the absorber circumferentially and averagely, which are capable of converting the vertical motion of the surface body to continuous rotation of the absorber and leading to a great increase in efficiency. A physical prototype was built to test the performance of the novel generator and optimize the design parameters. In the experiment part, a linear motion electric cylinder was used as the drive power to provide the heaving motion for the device. And the experiment platform was built for modeling a marine environment. Also, a data acquisition program was edited in Labview. Thus, the experiment analyzed the influence of amplitude, frequency, blade angle and resistance value to the output power, and then obtained the optimum parameters combination which can maximize the value of the output power. The result will provide reference for the device’s further application.

scholarly journals Kinerja Model Fisik Konverter Energi Ombak Rangkaian Gear Searah pada Periode Ombak yang Bervariasi

2016 ◽  
Vol 22 (2) ◽  
pp. 71 ◽  
Author(s):  
Masjono Muchtar ◽  
Salama Manjang ◽  
Dadang A Suriamiharja ◽  
M Arsyad Thaha
Keyword(s):  
Physical Model ◽  
Wave Energy ◽  
Ocean Waves ◽  
Wave Energy Converter ◽  
Wave Period ◽  
Physical Model Test ◽  
Energy Converter ◽  
Wave Flume ◽  
Period Variations ◽  
Hydraulics Laboratory

To date there were few research on the effect of non-linearity properties of the ocean waves on the performance of wave energy converter (WEC), which uses a series of unidirectional gear. One such parameter is the variation of wave period. The influence of wave period variations on the performance of physical model of the wave energy converters have been investigated at the Hydraulics Laboratory, Department of Civil Engineering, Hasanuddin University Indonesia. This WEC physical model was fabricated and assembled at Politeknik ATI Makassar Indonesia. The investigation steps consists of physical model development, physical model investigation at wave flume prior to the wave period  variation, measuring input output parameters of the physical model under test and empirical model formulation based on observed data analysis. Physical model test carried out on the wave flume at the Hydraulics Laboratory of the Department of Civil Hasanuddin University, at a water depth of 25 cm, wave height between 5-9 cm and wave period between 1.2 - 2.2 seconds. Investigation result based on flywheel radial speed (RPM) and torque (Nm) indicated that calculated harvested power was inversely proportional with the wave period. The longer the period of the waves, the energy produced is getting smaller. The derived empirical formula was y = -85.598x + 208.53 and R² = 0.8881. Y is energy produced (Watt) and X is the wave period (Second). Formulations generated from this study could be used as a reference for future research in dealing with wave period variations on a design one way gear wave energy converter as a source of renewable energy.

scholarly journals Hydroelectromechanical modelling of a piezoelectric wave energy converter

2016 ◽  
Vol 472 (2195) ◽  
pp. 20160715 ◽  
Author(s):  
E. Renzi
Keyword(s):  
Wave Energy ◽  
Water Waves ◽  
Numerical Approach ◽  
Wave Energy Converter ◽  
Flexural Wave ◽  
Energy Converter ◽  
Flow Equations ◽  
Ocean Surface Waves ◽  
In Series ◽  
Surface Water Waves

We investigate the hydroelectromechanical-coupled dynamics of a piezoelectric wave energy converter. The converter is made of a flexible bimorph plate, clamped at its ends and forced to motion by incident ocean surface waves. The piezoceramic layers are connected in series and transform the elastic motion of the plate into useful electricity by means of the piezoelectric effect. By using a distributed-parameter analytical approach, we couple the linear piezoelectric constitutive equations for the plate with the potential-flow equations for the surface water waves. The resulting system of governing partial differential equations yields a new hydroelectromechanical dispersion relation, whose complex roots are determined with a numerical approach. The effect of the piezoelectric coupling in the hydroelastic domain generates a system of short- and long-crested weakly damped progressive waves travelling along the plate. We show that the short-crested flexural wave component gives a dominant contribution to the generated power. We determine the hydroelectromechanical resonant periods of the device, at which the power output is significant.

scholarly journals Wave flume testing of an oscillating-body wave energy converter with a tuned inerter

2020 ◽  
Vol 98 ◽  
pp. 102127 ◽  
Author(s):  
Keita Sugiura ◽  
Ryoko Sawada ◽  
Yudai Nemoto ◽  
Ruriko Haraguchi ◽  
Takehiko Asai
Keyword(s):  
Wave Energy ◽  
Body Wave ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
Wave Flume

scholarly journals The Wave Energy Converter Design Process: Methods Applied in Industry and Shortcomings of Current Practices

2020 ◽  
Vol 8 (11) ◽  
pp. 932
Author(s):  
Ali Trueworthy ◽  
Bryony DuPont
Keyword(s):  
Design Process ◽  
Wave Energy ◽  
Academic Research ◽  
Optimization Methods ◽  
Wave Energy Converter ◽  
Design Parameters ◽  
Energy Converter ◽  
Design Decisions ◽  
Energy Technologies ◽  
Converter Design

Wave energy is among the many renewable energy technologies being researched and developed to address the increasing demand for low-emissions energy. The unique design challenges for wave energy converter design—integrating complex and uncertain technological, economic, and ecological systems, overcoming the structural challenges of ocean deployment, and dealing with complex system dynamics—have lead to a disjointed progression of research and development. There is no common design practice across the wave energy industry and there is no published synthesis of the practices that are used by developers. In this paper, we summarize the methods being employed in WEC design as well as promising methods that have yet to be applied. We contextualize these methods within an overarching design process. We present results from a survey of WEC developers to identify methods that are common in industry. From the review and survey results, we conclude that the most common methods of WEC design are iterative methods in which design parameters are defined, evaluated, and then changed based on evaluation results. This leaves a significant space for improvement of methods that help designers make better-informed decisions prior to sophisticated evaluation, and methods of using the evaluation results to make better design decisions during iteration. Despite the popularity of optimization methods in academic research, they are less common in industry development. We end this paper with a summary of the areas of WEC design in which the testing and development of new methods is necessary, and where more research is required to fully understand the influence of design decisions on WEC performance.

Power Absorption Modeling and Optimization of a Point Absorbing Wave Energy Converter Using Numerical Method

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Jeremiah Pastor ◽  
Yucheng Liu
Keyword(s):  
Wave Energy ◽  
Wave Energy Converter ◽  
Domain Model ◽  
Boundary Element Methods ◽  
Damping Coefficient ◽  
Energy Converter ◽  
Incoming Wave ◽  
Power Absorption ◽  
Point Absorber ◽  
Spring Force

This paper presents, assesses, and optimizes a point absorber wave energy converter (WEC) through numerical modeling, simulation, and analysis. Wave energy conversion is a technology uniquely suited for assisting in power generation in the offshore oil and gas platforms. A linear frequency domain model is created to predict the behavior of the heaving point absorber WEC system. The hydrodynamic parameters are obtained with AQWA, a software package based on boundary element methods. A linear external damping coefficient is applied to enable power absorption and an external spring force is introduced to tune the point absorber to the incoming wave conditions. The external damping coefficient and external spring forces are the control parameters, which need to be optimized to maximize the power absorption. Two buoy shapes are tested and a variety of diameters and drafts are compared. Optimal shape, draft, and diameter of the model are then determined to maximize its power absorption capacity.

scholarly journals A Novel Method for Estimating Wave Energy Converter Performance in Variable Bathymetry Regions and Applications

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2092 ◽  
Author(s):  
Kostas Belibassakis ◽  
Markos Bonovas ◽  
Eugen Rusu
Keyword(s):  
Wave Field ◽  
Wave Energy ◽  
Water Waves ◽  
Bottom Topography ◽  
Wave Energy Converter ◽  
Diffraction Radiation ◽  
Floating Bodies ◽  
Energy Converter ◽  
Coupled Mode ◽  
Energy Absorbers

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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