Numerical Verification of the Tuned Inertial Mass Effect of a Wave Energy Converter

2017 ◽  
Author(s):  
Ruriko Haraguchi ◽  
Takehiko Asai
Keyword(s):  
Wave Energy ◽  
Inertial Mass ◽  
Mass Effect ◽  
Dominant Frequency ◽  
Wave Energy Converter ◽  
Numerical Verification ◽  
Energy Converter ◽  
Numerical Studies ◽  
In Series ◽  
Band Limited

This paper introduces the mechanism of a buoy-type wave energy converter (WEC) with a tuned inertial mass (TIM) mechanism. The TIM mechanism consists of a rotational mass and motor connected in series with a tuning spring. While it is common to control the current of the power take-off system, the stiffness of the spring is tuned in addition so that the inertial mass part resonates with the dominant frequency of the wave motion. The method to design the parameters to maximize the power generation capability is introduced and numerical studies for both narrowband and broadband sea states are carried out. It is shown that the proposed device demonstrates better energy harvesting performance compared to the WEC without the TIM mechanism to band-limited stationary random vibration.

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.

Design and Development of a Small Scale Ocean Current and Wave Energy Converter

2016 ◽  
Author(s):  
Tyler Johnson ◽  
Benjamin Phillips ◽  
Scott Ringuette ◽  
Mansour Zenouzi ◽  
James McCusker
Keyword(s):  
Wave Energy ◽  
Alternative Energy ◽  
Current Flow ◽  
Inertial Mass ◽  
Wave Energy Converter ◽  
Ocean Current ◽  
Energy Sources ◽  
Small Scale ◽  
Energy Converter ◽  
Mass System

The inability to tie into the electrical power grid drives mariners to search for alternative energy sources. One such alternative energy source is to harness the vast supply of kinetic and potential energies associated with ocean currents and waves. In the Ocean Current and Wave Energy Converter, a tandem system of an underwater turbine and a wave energy buoy is designed to provide power to a standard 12 volt marine battery. Subsurface energy in the form of current flow is harvested by a helical cross-flow Gorlov turbine. Kinetic surface wave energy is harnessed through an inertial mass system. This system utilizes a 360°, bidirectional, rotating mass enclosed in a spherical buoy that converts the pitching motion into rotational motion. Both subsystems are integrated together through the charging circuit. The charging system is designed to integrate multiple energy sources to maximize the total energy harnessed. Through testing and analysis, design improvements are identified and it is determined that the design of a small scale current flow and wave energy conversion system is a feasible solution to providing power from the ocean.

Study on the Hydrodynamics of a Single-Acting Pendulum Wave Energy Converter

2014 ◽  
Vol 518 ◽  
pp. 209-214 ◽  
Author(s):  
Dong Jiao Wang ◽  
Shou Qiang Qiu ◽  
Jia Wei Ye
Keyword(s):  
Wave Energy ◽  
Three Dimensional ◽  
Time Domain Analysis ◽  
Wave Energy Converter ◽  
Regular Waves ◽  
Energy Converter ◽  
Numerical Studies ◽  
Motion Responses ◽  
Pendulum Wave Energy Converter ◽  
Pendulum Wave

Based on the three dimensional potential theory, numerical studies were carried out to investigate the hydrodynamics of a single-acting trapezoidal pendulum wave energy converter in regular waves by using time domain analysis. The nonlinear viscous damping was also taken into account, and the influence of power take-off damping on the motion responses and output performances were analyzed. Comparisons of experimental and numerical results were performed as part of the validation process.

scholarly journals Enhanced power absorption of a point absorber wave energy converter using a tuned inertial mass

2020 ◽  
Author(s):  
Ruriko Haraguchi ◽  
Takehiko Asai
Keyword(s):  
Power Generation ◽  
Energy Absorption ◽  
Wave Energy ◽  
Inertial Mass ◽  
Wave Energy Converter ◽  
Primary System ◽  
Energy Converter ◽  
Power Absorption ◽  
Point Absorber ◽  
Power Generation Performance

A novel point absorber wave energy converter with a tuned inertial mass (TIM), which is capable of significantly increasing the energy absorption and broadening the effective bandwidth, is proposed in this paper. The mechanism of the TIM has originally been introduced in the field of civil engineering as a passive energy absorber for structures subjected to external loadings such as earthquakes. It relies on attaching an additional tuning spring and a rotational inertial mass to the primary system, to improve the energy absorption performance by amplifying the displacement of the damper. Thus, considering typical point absorbers modeled as a mass-spring-dashpot system similar way to civil structures, the application of the TIM to wave energy converters can be expected to have a significant effect. In this paper, numerical investigation on the power generation performance of a point absorber with the TIM is conducted under random sea waves. The amplitude response and power generation performance are compared with the conventional point absorber, considering both non-resonant and resonant buoy cases. It is shown that by properly designing the tuning spring stiffness and generator damping, the rotation of the generator can be amplified compared to the buoy, increasing the power absorption drastically.

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