scholarly journals Hydrodynamic Performance of an Asymmetry OWC Device Mounted on a Box-Type Breakwater

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhengzhi Deng ◽  
Pinjie Wang ◽  
Pengda Cheng
Keyword(s):  
Energy Conversion ◽  
Wave Height ◽  
Incident Wave ◽  
Wave Energy ◽  
Short Wave ◽  
Absorption Efficiency ◽  
Hydrodynamic Performance ◽  
Maintenance Cost ◽  
Wave Energy Conversion ◽  
Coupling System

To share the construction and maintenance cost, an asymmetric oscillating water column (OWC) device integrated with a pile-fixed box-typed offshore breakwater is considered experimentally and numerically. A fully nonlinear numerical wave tank is established and validated with the open source solver OpenFOAM. The effects of the width and draft of rear box, and the incident wave height on the wave energy conversion efficiency, reflection and transmission coefficients, and energy dissipation coefficient are examined. In addition, the superiority of the present coupling system, compared to the traditional box-type breakwater, is discussed. With well comparisons, the results show that the existence of the rear breakwater is beneficial for the formation of partial standing waves and further wave energy conversion. In the range of wave heights tested, the higher the incident wave height, the larger the energy absorption efficiency except for the short-wave regimes. Moreover, the OWC-breakwater coupling system can obtain a similar wave blocking ability to the traditional one, and simultaneously extract wave energy and decrease wave reflection.

Design of a Linear Generator for Wave Energy Conversion in Peninsular Malaysia

2015 ◽  
Vol 793 ◽  
pp. 363-367
Author(s):  
Mohd. Aizuddin Firdaus Mohmad Hamim ◽  
Taib Ibrahim ◽  
Nursyarizal Mohd Nor
Keyword(s):  
Energy Conversion ◽  
Permanent Magnet ◽  
Wave Energy ◽  
Flux Distribution ◽  
Open Circuit ◽  
Maintenance Cost ◽  
Direct Drive ◽  
Wave Energy Conversion ◽  
Linear Generator ◽  
Permanent Magnet Generator

Malaysia is a small country surrounded by numerous oceans that can provide sufficient renewable energy for utilization. This work is to propose a design and modeling of a portable linear permanent magnet generator for the Wave Energy Conversion system that suits with the local wave parameters. Linear generator is preferable as compared to the rotary generator due to the direct drive technology that promises low maintenance cost. Three linear permanent magnet generator designs with different types of permanent magnet layout have been proposed as the permanent magnet used can provide better flux density compared to other topologies. Preliminary results for the air gap flux distribution and open-circuit flux distribution are demonstrated and discussed are shown to be as expected.

An Analysis of a Stationary Pneumatic Wave-Energy Converter

1975 ◽  
Vol 97 (3) ◽  
pp. 1015-1019 ◽  
Author(s):  
Michael E. McCormick
Keyword(s):  
Theoretical Analysis ◽  
Energy Conversion ◽  
Wave Height ◽  
Wave Energy ◽  
Power Output ◽  
Peak Power ◽  
Peak Power Output ◽  
Wave Energy Conversion ◽  
Energy Converter ◽  
Resonant Period

A theoretical analysis of a stationary pneumatic wave-energy conversion device is presented. Results obtained from the analysis show that the power converted is proportional to the cube of the wave height, producing a maximum time-averaged power per wave period of 25 kw for a 20-ft (6.096 m) diameter unit located in a 3-ft (0.9144 m) sea. The device can be adjusted for purposes of efficiency in any sea spectrum by simply changing the draft (length of the centerpipe) of the unit. The peak power output of the device occurs at a period similar to the resonant period of a surge chamber.

Numerical investigation of front-wall inclination effects on the hydrodynamic performance of a fixed oscillation water column wave energy converter

2018 ◽  
Vol 233 (2) ◽  
pp. 262-271
Author(s):  
M Anbarsooz ◽  
H Rashki ◽  
A Ghasemi
Keyword(s):  
Water Column ◽  
Wave Height ◽  
Wave Energy ◽  
Nonlinear Waves ◽  
Absorption Efficiency ◽  
Hydrodynamic Performance ◽  
Front Wall ◽  
Oscillating Water Column ◽  
Wave Tank ◽  
Highly Nonlinear

One of the main geometrical parameters of the fixed oscillating water column wave energy converters is the inclination angle of front wall. In this study, the effects of this parameter on the hydrodynamic performance of an oscillating water column is investigated using a fully nonlinear two-dimensional numerical wave tank, which is developed using the Ansys Fluent 15.0 commercial software. The accuracy of the developed wave tank is first examined by simulating an oscillating water column, having a front wall normal to the water-free surface, subjected to linear, small amplitude incident waves. The resultant absorption efficiencies are compared with available analytical data in the literature, where a good agreement was observed. Next, the simulations are performed for strongly nonlinear waves, up to the wave steepness of 0.069 ( H/L = 0.069), where H is the wave height and L is the wave length. Results show that the absorption efficiency of the oscillating water column decreases considerably as the wave height increases. Moreover, the maximum wave energy absorption efficiency for the highly nonlinear waves occurs at a pneumatic damping coefficient lower than that of the linear theory. Then, the absorption efficiency of the oscillating water column is determined for eight various front wall configurations at various incident wave periods. Results show that, the front walls that are slightly bent towards the inner region of the oscillating water column chamber are more efficient at some wave periods in comparison with the cases studied in this paper.

scholarly journals Hydrodynamic Performance of a Pitching Float Wave Energy Converter

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1801
Author(s):  
Yong Ma ◽  
Shan Ai ◽  
Lele Yang ◽  
Aiming Zhang ◽  
Sen Liu ◽  
...  
Keyword(s):  
Energy Conversion ◽  
Frequency Domain ◽  
Wave Energy ◽  
Center Of Mass ◽  
Hydrodynamic Performance ◽  
Irregular Waves ◽  
Wave Energy Conversion ◽  
Wave Direction ◽  
Improved Stability ◽  
The Time Domain

This study analyzes the hydrodynamic performance and application of a pitching float-type wave energy conversion device under complex sea conditions in the South China Sea. Potential flow theory and ANSYS-AQWA software are used to establish a method for analyzing hydrodynamic performance in both time and frequency domains, as well as the various factors that influence hydrodynamic performance. The frequency domain characteristics of the conversion device are explored, as well as the time-domain characteristics when exposed to regular and irregular waves. The results show that the frequency domain of hydrodynamic performance conforms to the requirements of an offshore mobile platform. A mooring point that is closer to the center of mass leads to improved stability of the conversion device. The angle arrangement of the anchor-chain mooring method fully conforms to safety requirements. When the wave direction is 45°, the conversion device is highly stressed and its movement is the most strenuous; however, the device can operate safely and stably under all working conditions. These results provide a significant reference for expanding the wave-energy capture range and the hydrodynamic performance of floating wave-energy conversion devices.

scholarly journals IMPLEMENTATION AND TESTING OF A POWER MATRIX-BASED WAVE ENERGY CONVERSION MODEL AND THE EFFECT SIMULATED ON THE WAVE FIELD — CASE STUDY OF LAGUNA, SC, BRAZIL

2019 ◽  
Vol 18 (1) ◽  
pp. 50
Author(s):  
P. H. Oleinik ◽  
W. C. Marques
Keyword(s):  
Energy Conversion ◽  
Wave Height ◽  
Wave Energy ◽  
Significant Wave Height ◽  
Renewable Energy Sources ◽  
Electrical Energy ◽  
Ocean Waves ◽  
Wave Energy Conversion ◽  
Significant Wave ◽  
Order Of Magnitude

Electrical energy has become an essential resource for mankind and, as the population and technological dependency grow, also does the electricity demand. This necessity boosted numerous studies which focus on clean and renewable energy sources. Ocean wave energy is one of the most environmentally friendly sources of energy since it does not emit pollutants to the atmosphere and does not produce harmful waste. Another positive point about ocean waves is that they are inexhaustible, therefore a power plant could, potentially, provide energy indefinitely. Hence the object of this study is to estimate the wave energy reduction caused by the presence of wave energy conversion (WEC) devices near the coastline of Laguna, Brazil. In order to study the coastal impact of a WEC farm, the third generation sea state model TOMAWAC was used to simulate the waves on the Southern Brazilian Shelf under two different conditions, with and without the presence of an array of WECs. The results show that the mean significant wave height in the blockaded area undergoes a slight drop, caused by the presence of the WECs, which do not appear in the other scenario. But this reduction of the significant wave height is negligible compared to the order of magnitude of the wave height itself.

The Wave Focusing Effect of a Parabolic Wall

2004 ◽  
Author(s):  
J. Wang ◽  
S. M. Calisal ◽  
J. Mikkelsen ◽  
S. Zealand
Keyword(s):  
Energy Conversion ◽  
Wave Height ◽  
Wave Energy ◽  
Relative Size ◽  
Experimental Results ◽  
Wave Forces ◽  
Wave Energy Conversion ◽  
Height Measurement ◽  
Wave Focusing ◽  
Wall Area

The energy generation efficiency of a wave energy conversion system is in general proportional to the capacity of wave energy capture of the system. In various wave energy conversion systems, a configuration with parabolic shape has shown advantages in wave capture dynamics. This paper presents an experimental investigation into the wave focusing and elevation in a parabolic wall area with a Laser Wave Height Measurement equipment named as IVP Ranger SC386. In the experiment, the tested waves were described by a dimensionless factor WF which consists of wave parameters and the parabolic wall size. The WF increases with wave relative size to the model. The tested wave obliquities to the parabolic wall were 10 and 20 degrees in addition to the normal incident waves. A tube with an inner diameter 7.5cm, representing a chamber for oscillatory water columns compressing air, was mounted at the focus area. The elevations of wave height inside the tube with a sealed and an open top, as two different cases, were also measured. Furthermore the wave forces acting on the parabolic wall were measured using load cells. The analysis of the experimental results revealed that the parabolic wall was able to significantly elevate wave heights by up to 2.5 times. Within 10 degrees the wave obliquity effect can be neglected for both forces acting on the parabolic wall and wave height elevated by the parabolic wall. A prediction equation for focusing wave height was developed from the experimental results and the parabolic focusing principle.

Sign in / Sign up

Export Citation Format

Share Document