scholarly journals Performance of an U-Shaped Oscillating Water Column Wave Energy Converter Device under Oblique Incident Waves

Fluids ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 137
Author(s):  
Kshma Trivedi ◽  
Santanu Koley ◽  
Kottala Panduranga
Keyword(s):  
Water Column ◽  
Structural Parameters ◽  
Physical Parameters ◽  
Front Wall ◽  
Angle Of Incidence ◽  
Oscillating Water Column ◽  
Energy Converter ◽  
Chamber Length ◽  
Wide Range ◽  
Incident Waves

The present study deals with the performance of an U-shaped oscillating water column device under the action of oblique incident waves. To solve the associated boundary value problem, the dual boundary element method (DBEM) is used. Various physical parameters associated with the U-shaped OWC device, such as the radiation susceptance and conductance coefficients, and the hydrodynamic efficiency, are analyzed for a wide range of wave and structural parameters. The study reveals that the resonance in the efficiency curve occurs for smaller values of wavenumber with an increase in chamber length, submergence depth of the front wall and opening duct, and width of the opening duct. It is observed that with appropriate combinations of the angle of incidence and incident wavenumber, more than 90% efficiency in the U-shaped OWC device can be achieved.

scholarly journals The Influence of the Chamber Configuration on the Hydrodynamic Efficiency of Oscillating Water Column Devices

2020 ◽  
Vol 8 (10) ◽  
pp. 751
Author(s):  
Ayrton Alfonso Medina Rodríguez ◽  
Jesús María Blanco Ilzarbe ◽  
Rodolfo Silva Casarín ◽  
Urko Izquierdo Ereño
Keyword(s):  
Water Column ◽  
Wall Thickness ◽  
Water Waves ◽  
Numerical Results ◽  
Physical Parameters ◽  
Front Wall ◽  
Linear Wave ◽  
Oscillating Water Column ◽  
Wave Regime ◽  
The Impact

Based on the two-dimensional linear wave theory, the effects of the front wall thickness and the bottom profile of an Oscillating Water Column (OWC) device on its efficiency were analyzed. Using the potential flow approach, the solution of the associated boundary value problem was obtained via the boundary element method (BEM). Numerical results for several physical parameters and configurations were obtained. The effects of the front wall thickness on the efficiency are discussed in detail, then, various configurations of the chamber bottom are presented. A wider efficiency band was obtained with a thinner front wall. In a real scenario having a thinner front wall means that such a structure could have less capacity to withstand the impact of storm waves. Applying the model for the case of the Mutriku Wave Energy Plant (MWEP), findings showed that the proposed bottom profiles alter the efficiency curve slightly; higher periods of the incoming water waves were found. This could increase the efficiency of the device in the long-wave regime. Finally, the numerical results were compared with those available in the literature, and were found to be in good agreement.

Numerical Analysis of the Oscillating Water Column (OWC) Wave Energy Converter (WEC) Considering Different Incident Wave Height

2017 ◽  
Vol 370 ◽  
pp. 120-129
Author(s):  
Mateus das Neves Gomes ◽  
Eduardo Alves Amado ◽  
Elizaldo Domingues dos Santos ◽  
Liércio André Isoldi ◽  
Luiz Alberto Oliveira Rocha
Keyword(s):  
Water Column ◽  
Wave Height ◽  
Incident Wave ◽  
Wave Energy ◽  
Amplification Factor ◽  
Wave Energy Converter ◽  
Geometric Shape ◽  
Oscillating Water Column ◽  
Energy Converter ◽  
Incident Waves

The ocean wave energy conversion into electricity has been increasingly researched in the last years. There are several proposed converters, among them the Oscillating Water Column (OWC) device has been widely studied. The present paper presents a two-dimensional numerical investigation about the fluid dynamics behavior of an OWC Wave Energy Converter (WEC) into electrical energy. The main goal of this work was to numerically analyze the optimized geometric shape obtained in previous work under incident waves with different heights. To do so, the OWC geometric shape was kept constant while the incident wave height was varied. For the numerical solution it was used the Computational Fluid Dynamic (CFD) commercial code FLUENT®, based on the Finite Volume Method (FVM). The multiphasic Volume of Fluid (VOF) model was applied to tackle with the water-air interaction. The computational domain is represented by the OWC device coupled with the wave tank. This work allowed to check the influence of the incident wave height on the hydropneumatic power and the amplification factor of the OWC converter. It was possible to identify that the amplification factor increases as the wave period increases, thereby improving the OWC performance. It is worth to highlight that in the real phenomenon the incident waves on the OWC device have periods, lengths and height variables.

Estimation of Cumulative Output Energy of Oscillating Water Column Wave Energy Converter Considering Power Take Off Damping

2020 ◽  
Author(s):  
Mitsumasa Iino ◽  
Takeaki Miyazaki ◽  
Makoto Iida
Keyword(s):  
Water Column ◽  
Output Power ◽  
Wave Period ◽  
Maximum Efficiency ◽  
Water Tank ◽  
Oscillating Water Column ◽  
Energy Converter ◽  
Air Power ◽  
Wave Condition ◽  
Wide Range

Abstract The objective of this study is to investigate the influence of damping from the PTO device on the cumulative output of the oscillating water column wave energy converter under real sea conditions which encompasses wide range of wave period and height. In this presentation, a time domain dynamic simulation model of OWC motion is developed and validated with water tank test results. Then the model is used to calculate a wide range of wave period and height. Finally, annual cumulative air power output of OWC is calculated with different damping values. In the water tank experiment, a cylindrical oscillating water column with a diameter of 0.3 m and submerged depth of 0.2 m is tested. PTO damping was emulated by using several orifice plates. Since the orifice pressure is proportional to square of flow-rate of the orifice, In the simulation, a model was constructed to solve the dynamic equation of motion assuming water column as a rigid equivalent floating body. Validation showed the model captures the influence of PTO damping as observed in the water tank testing. Using simulation, output air power from real scale OWC was evaluated under wide range of inlet wave period and height. With the output power database from dynamic simulation and frequency of wave height and period at specific sites in Japan (Fukui and Kamaishi), annual cumulative output power is calculated. From the results, it was confirmed that a higher output can be obtained with higher energy in high waves by adopting a damping characteristic that increases the efficiency under a wide wave condition rather than a nozzle characteristic that achieves maximum efficiency in the resonance period. Furthermore, it became clear that the damping that increases the maximum efficiency does not necessarily increase the accumulated energy. When considering operation in real sea condition in the future, it is not always effective to select PTO damping that maximizes the output at specific wave height or period. And it is important to adopt a method that can estimate wide range of wave condition and evaluate the cumulative output power.

scholarly journals Efficiency Assessment of an Amended Oscillating Water Column Using OpenFOAM

2021 ◽  
Vol 13 (10) ◽  
pp. 5633
Author(s):  
Mobin Masoomi ◽  
Mahdi Yousefifard ◽  
Amir Mosavi
Keyword(s):  
Water Column ◽  
Numerical Investigation ◽  
Open Field ◽  
Wave Energy ◽  
Wave Energy Converter ◽  
Navier Stokes ◽  
Front Wall ◽  
Oscillating Water Column ◽  
Energy Converter ◽  
Efficiency Assessment

oscillating water column (OWC) is an advanced form of wave energy converter (WEC). This study aims at improving the efficiency of an amended OWC through a novel methodology for simulating several vertical plates within the chamber. This paper provides a numerical investigation considering one, two, three, and four vertical plates. The open field operation and manipulation (OpenFOAM) solver is verified based on the Reynolds-Averaged Navier–Stokes (RANS) equation. Results show the number and the position of plates where the convertor’s efficiency improves. The work undertaken here also revealed a reduction in the net force imposed on the convertor’s structure, especially the front wall. Consequently, adding plates acquires more efficiency with lower force on the system.

scholarly journals The Effect of the Beat Phenomenon on the Oscillating Water Column Device

2020 ◽  
Vol 55 (1) ◽  
Author(s):  
Jahirwan Ut Jasron ◽  
Sudjito Soeparman ◽  
Lilis Yuliati ◽  
Djarot B. Darmadi
Keyword(s):  
Water Column ◽  
Energy Conversion Efficiency ◽  
Maximum Energy ◽  
Maximum Efficiency ◽  
Front Wall ◽  
Relative Depth ◽  
Oscillating Water Column ◽  
Natural Type ◽  
Beat Phenomenon ◽  
Incident Waves

The oscillating water column is the most natural type of wave energy converter because of its simple mechanical structure. To achieve maximum energy conversion efficiency, the incident waves and the natural frequency of the device’s construction have to be in resonance. This paper discusses the beat phenomenon as a form of resonance and several factors that allow the beating to occur, namely the relative depth of the wave (h/L) and the ratio of the submerged front wall length to the water depth (a/h), and their effect on oscillating water column efficiency. The test results show that the beat phenomenon occurs in the wave period T = 1.7 s, with a maximum efficiency of 22.12% achieved at conditions h/L = 0.114 and a/h = 0.4.

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