Computer Modeling of Wave-Energy Air Turbines With the SUPG/PSPG Formulation and Discontinuity-Capturing Technique

2011 ◽  
Vol 79 (1) ◽  
Author(s):  
A. Corsini ◽  
F. Rispoli ◽  
T. E. Tezduyar
Keyword(s):  
Wave Energy ◽  
Wave Motion ◽  
Computational Fluid Mechanics ◽  
Computational Technique ◽  
Galerkin Methods ◽  
Computational Results ◽  
Wells Turbine ◽  
Rans Modeling ◽  
Numerical Performance

We present a computational fluid mechanics technique for modeling of wave-energy air turbines, specifically the Wells turbine. In this type of energy conversion, the wave motion is converted to an oscillating airflow in a duct with the turbine. This is a self-rectifying turbine in the sense that it maintains the same direction of rotation as the airflow changes direction. The blades of the turbine are symmetrical, and here we consider straight and swept blades, both with constant chord. The turbulent flow physics involved in the complex, unsteady flow is governed by nonequilibrium behavior, and we use a stabilized formulation to address the related challenges in the context of RANS modeling. The formulation is based on the streamline-upwind/Petrov-Galerkin and pressure-stabilizing/Petrov-Galerkin methods, supplemented with the DRDJ stabilization. Judicious determination of the stabilization parameters involved is also a part of our computational technique and is described for each component of the stabilized formulation. We compare the numerical performance of the formulation with and without the DRDJ stabilization and present the computational results obtained for the two blade configurations with realistic airflow data.

scholarly journals WAVE FORCES ON PILES IN RELATION TO WAVE ENERGY SPECTRA

1968 ◽  
Vol 1 (11) ◽  
pp. 61
Author(s):  
A. Paape
Keyword(s):  
Energy Density ◽  
Probability Distribution ◽  
Wave Energy ◽  
Wave Motion ◽  
Irregular Waves ◽  
Energy Spectra ◽  
Wave Forces ◽  
Density Spectrum ◽  
The Waves

The determination of wave forces on piles is for an important part based upon data obtained with regular laboratory waves. Nonlmearities m the mechanism that underlies these forces may lead to deviations when applying the data to predict forces exerted by irregular waves. Experiments have been performed with irregular waves to investigate wave forces, more particularly to study the influence of the energy density spectrum of the waves. Within the range of conditions m the experiments, the wave motion is sufficiently characterized by its energy and the frequency (or wave period) at which the energy density is maximum to determine the probability distribution of wave forces.

scholarly journals A Piezoelectric Wave-Energy Converter Equipped with a Geared-Linkage-Based Frequency Up-Conversion Mechanism

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 204
Author(s):  
Shao-En Chen ◽  
Ray-Yeng Yang ◽  
Guang-Kai Wu ◽  
Chia-Che Wu
Keyword(s):  
Power Generation ◽  
Wave Energy ◽  
Wave Motion ◽  
Wave Energy Converter ◽  
Gear Train ◽  
Piezoelectric Composite ◽  
Maximum Height ◽  
Resistive Load ◽  
Linkage Mechanism ◽  
Energy Converter

In this paper, a piezoelectric wave-energy converter (PWEC), consisting of a buoy, a frequency up-conversion mechanism, and a piezoelectric power-generator component, is developed. The frequency up-conversion mechanism consists of a gear train and geared-linkage mechanism, which converted lower frequencies of wave motion into higher frequencies of mechanical motion. The slider had a six-period displacement compared to the wave motion and was used to excite the piezoelectric power-generation component. Therefore, the operating frequency of the piezoelectric power-generation component was six times the frequency of the wave motion. The developed, flexible piezoelectric composite films of the generator component were used to generate electrical voltage. The piezoelectric film was composed of a copper/nickel foil as the substrate, lead–zirconium–titanium (PZT) material as the piezoelectric layer, and silver material as an upper-electrode layer. The sol-gel process was used to fabricate the PZT layer. The developed PWEC was tested in the wave flume at the Tainan Hydraulics Laboratory, Taiwan (THL). The maximum height and the minimum period were set to 100 mm and 1 s, respectively. The maximum voltage of the measured value was 2.8 V. The root-mean-square (RMS) voltage was 824 mV, which was measured through connection to an external 495 kΩ resistive load. The average electric power was 1.37 μW.

A modified Wells turbine for wave energy conversion

2003 ◽  
Vol 28 (1) ◽  
pp. 79-91 ◽  
Author(s):  
T. Setoguchi ◽  
S. Santhakumar ◽  
M. Takao ◽  
T.H. Kim ◽  
K. Kaneko
Keyword(s):  
Energy Conversion ◽  
Wave Energy ◽  
Wave Energy Conversion ◽  
Wells Turbine

Potential of performance improvement of a modified Wells turbine using passive control for wave energy conversion

2021 ◽  
Vol 242 ◽  
pp. 110178
Author(s):  
Ahmed T.M. Kotb ◽  
Mohamed A.A. Nawar ◽  
Rafea Abd El Maksoud ◽  
Youssef A. Attai ◽  
Mohamed H. Mohamed
Keyword(s):  
Energy Conversion ◽  
Performance Improvement ◽  
Wave Energy ◽  
Passive Control ◽  
Wave Energy Conversion ◽  
Wells Turbine

Performance investigation of Wells turbine for wave energy conversion with stall cylinders

2021 ◽  
Vol 241 ◽  
pp. 110052
Author(s):  
Kaihe Geng ◽  
Ce Yang ◽  
Chenxing Hu ◽  
Yanzhao Li ◽  
Xin Shi
Keyword(s):  
Energy Conversion ◽  
Wave Energy ◽  
Wave Energy Conversion ◽  
Wells Turbine

Analysis of Wave Energy Sources in the North Atlantic Waters in View of Design Challenges

2016 ◽  
Author(s):  
Jose V. Taboada ◽  
Hirpa G. Lemu
Keyword(s):  
Renewable Energy ◽  
North Atlantic ◽  
Wave Energy ◽  
Energy Resources ◽  
Structural Performance ◽  
Energy Sources ◽  
Wave Power ◽  
Wave Statistics ◽  
Wave Characteristics

This paper describes a wave energy analysis of North Atlantic waters and provides an overview of the available resources. The analysis was conducted using a scatter diagram data combined with wave statistics and empirical parameters given by wave height and periods. Such an overview is instrumental for modelling of wave energy sources, design of wave energy converter (WEC) devices and determination of locations of the devices. Previous survey of wave energy resources widely focused on determination of the reliability on installations of WECs. Though the renewable energy source that can be utilized from the waves is huge, the innovative work in design and development of WECs is insignificant and the available technologies still require further optimization. Furthermore, the wave potential of North Atlantic waters is not sufficiently studied and documented. Closer review of the literature also shows that wave energy conversion technology, compared with other conversion machines of renewable energy sources such as wind energy and solar energy, seems still immature and most of the research and development efforts in this direction are limited in scope. The design of energy converters is also highly dictated by the wave energy resource intensity distribution, which varies from North to South hemisphere. The immaturity of the technology can be attributed to several factors. Since there are a number of uncertainties on the accuracy of wave data, the design, location and installation of WECs face a number of challenges in terms of their service life, structural performance and topological configuration. As a result, collection and assessment of wave characteristics and the wave state conditions data serve as key inputs for development of robust, reliable, operable and affordable wave energy converters. The fact that a number of variables are involved in wave distribution characteristics and the extraction of wave power, treating these variables in the design process imposes immense challenges for the design optimization and hence the optimum energy conversion. The conversion machines are expected to extract as high wave energy as possible while their structural performance is ensured. The study reported in this paper is to analyse wave data over several years of return periods with a detailed validation for wave statistics and wave power. The analysis is intended to contribute in better understanding of the wave characteristics with influencing parameters that can serve as design optimization parameters. A method is proposed to conduct a survey and analysis of the available wave energy resources and the potential at cited locations. The paper concludes that wave energy data accuracy is the baseline for project scoping, coastal and offshore design, and environmental impact assessments.

scholarly journals WAVE TRANSMISSION THROUGH TRAPEZOIDAL BREAKWATERS

1978 ◽  
Vol 1 (16) ◽  
pp. 129 ◽  
Author(s):  
Ole Secher Madsen ◽  
Paisal Shusang ◽  
Sue Ann Hanson
Keyword(s):  
Energy Dissipation ◽  
Approximate Method ◽  
Cross Section ◽  
Wave Energy ◽  
Graphical Form ◽  
Dissipated Energy ◽  
Simple Method ◽  
Reflection And Transmission ◽  
Transmission Coefficients

In a previous paper Madsen and White (1977) developed an approximate method for the determination of reflection and transmission characteristics of multi-layered, porous rubble-mound breakwaters of trapezoidal cross-section. This approximate method was based on the assumption that the energy dissipation associated with the wave-structure interaction could be considered as two separate mechanisms: (1) an external, frictional dissipation on the seaward slope; (2) an internal dissipation within the porous structure. The external dissipation on the seaward slope was evaluated from the semi-theoretical analysis of energy dissipation on rough, impermeable slopes developed by Madsen and White (1975). The remaining wave energy was represented by an equivalent wave incident on a hydraulically equivalent porous breakwater of rectangular cross-section. The partitioning of the remaining wave energy among reflected, transmitted and internally dissipated energy was evaluated as described by Madsen (1974), leading to a determination of the reflection and transmission coefficients of the structure. The advantage of this previous approximate method was its ease of use. Input data requirements were limited to quantities which would either be known (water depth, wave characteristics, breakwater geometry, and stone sizes) or could be estimated (porosity) by the design engineer. This feature was achieved by the employment of empirical relationships for the parameterization of the external and internal energy dissipation mechanisms. General solutions were presented in graphical form so that calculations could proceed using no more sophisticated equipment than a hand calculator (or a slide rule). This simple method gave estimates of transmission coefficients in excellent agreement with laboratory measurements whereas its ability to predict reflection coefficients left a lot to be desired.

A Comparison of Self-Rectifying Turbines for OWC Based Wave Energy Power Extracting Device Using Numerical Simulation

2002 ◽  
Author(s):  
A. R. Ansari ◽  
H. B. Khaleeq ◽  
A. Thakker
Keyword(s):  
Numerical Simulation ◽  
Wave Energy ◽  
Sea Water ◽  
Time History ◽  
Flow Conditions ◽  
Wells Turbine ◽  
Impulse Turbine ◽  
Simulation Techniques ◽  
Simple Geometry ◽  
Wide Range

This paper presents a comparison of self-rectifying turbines for the Oscillating Water Column (OWC) based Wave Energy power extracting device using numerical simulation. The two most commonly used turbines for OWC based devices, the Impulse and the Wells turbines were evaluated under real sea simulated conditions. Assuming the quasi-steady condition, experimental data for both 0.6m turbines with 0.6 hub to tip ratio was used to predict their behavior under real sea conditions. The real sea water surface elevation time history data was used to simulate the flow conditions using standard numerical simulation techniques. A simple geometry of the OWC was considered for the simulation. The results show that the overall mean performance of an Impulse turbine is better than the Wells turbine under unsteady, irregular real sea conditions. The Impulse turbine was observed to be more stable over a wide range of flow conditions. This paper reports the comparison of performance characteristics of both these turbines under simulated real sea conditions.

Sign in / Sign up

Export Citation Format

Share Document