scholarly journals A CFD Study with Fuzzy Logic Pitch Angle Turbine Control Implementation for OWC Generation System

2017 ◽  
Vol 6 (2) ◽  
pp. 175
Author(s):  
Mansour Madaci ◽  
Djallel Kerdoun
Keyword(s):  
Pitch Angle ◽  
Wave Model ◽  
Sea Waves ◽  
Generation System ◽  
Fem Model ◽  
Wave Generator ◽  
The Waves ◽  
Fast Variation ◽  
Extracted Power ◽  
Control Implementation

The paper takes the improvement of the performance for an OWC converter from the mechanical side. A FEM model of the OWC conversion structure was proposed, studied and simulated using a CFD simulator. A novel wave generation method was applied through the RWMD method (Real Wave Model Simulator) instead of using an ordinary sin wave generator on the tank to make the waves the closest possible to the real sea waves. A mechanical prototype was built for this purpose to get an oscillated wave model. On the electrical side, a pitch angle control system based on fuzzy set was applied on the turbine to be auto-adapted for the fast variation of the airflow speed to establish and maximize the extracted power from the OWC device. The model have been studied, simulated, implemented and tested to validate the obtained results.

Wave power extraction from an oscillating water column at the tip of a breakwater

2009 ◽  
Vol 626 ◽  
pp. 395-414 ◽  
Author(s):  
HERVÉ MARTINS-RIVAS ◽  
CHIANG C. MEI
Keyword(s):  
Water Column ◽  
Angle Of Incidence ◽  
Oscillating Water Column ◽  
Sea Waves ◽  
Power Extraction ◽  
Grid Connection ◽  
Simple Geometry ◽  
Construction Operation ◽  
The Waves ◽  
Extracted Power

To reduce the costs of construction, operation, maintenance, energy storage and grid connection, some devices for extracting energy from sea waves are likely to be installed on the coast. We study theoretically a single oscillating water column (OWC) installed at the tip of a long and thin breakwater. The linearized problems of radiation and scattering for a hollow cylinder with an open bottom are then solved by the usual method of eigenfunction expansions and integral equations. Since a thin breakwater is the limit of a wedge, an exact solution for the diffraction by a solid cylinder at the tip of a wedge is derived to facilitate the analysis. Following Sarmento & Falcão (J. Fluid Mech., vol. 150, 1985, pp. 467–485), power takeoff by Wells turbines is modelled by including air compressibility in the chamber above the water surface. The effects of air compressibility on the extraction efficiency is studied. It is shown that for this simple geometry the angle of incidence affects the waves outside the structure but not the extracted power.

Wind speed data analysis for predictions of sea waves in Bitung Coastal Waters

2013 ◽  
pp. 35 ◽  
Author(s):  
Joanes E Koagouw ◽  
Gybert E Mamuaya ◽  
Adrie A Tarumingkeng ◽  
P A Angmalisang
Keyword(s):  
Data Analysis ◽  
Wind Speed ◽  
Coastal Waters ◽  
Transition Period ◽  
Marine Resources ◽  
Land Uses ◽  
Sea Waves ◽  
North West ◽  
North Sulawesi ◽  
The Waves

Coastal area of Bitung Municipality is one of the economical activities centers in North Sulawesi Province such as for land-uses and the exploitation of natural resources. Those activities are exaggerating day bay day and tended to be uncontrollable. The excess of those conditions, it has been recorded the change of waves in Bitung waters that has impacts to coastal areas and can affect the utilization of coastal and marine resources. This research was aimed to observe waves altitude variations in Bitung waters with Svedrup Munk and Bretchsneider (SMB) method that had been used to predict waves altitudes. The results showed that the wind speed during West Season was 0.33 m and were dominant to the East, while during East season was 0.91m from South-East to North-West, and then on transition period (March to May) was 1.08m from South-East to East. The results of those wind speed to the waves altitudes in Bitung waters is discussed in this paper© Pesisir pantai Kota Bitung merupakan salah satu pusat aktivitas ekonomi (misalnya pemanfaatan lahan dan eksploitasi sumberdaya) di Provinsi Sulawesi Utara. Aktivitas tersebut semakin hari semakin meningkat dan memiliki kecenderungan tidak terkontrol. Akibat dari keadaan tersebut, telah terjadi perubahan fenomena gelombang di perairan Bitung yang berdampak pada keberadaan daerah pesisir pantai di mana hal ini dapat mengganggu aktivitas pemanfaatan sumberdaya pesisir dan laut tersebut. Penelitian ini bertujuan untuk mengetahui variasi tinggi gelombang di perairan Bitung dengan menggunakan metode Svedrup Munk and Bretchsneider (SMB) yang biasa digunakan untuk peramalan tinggi gelombang signifikan. Hasil penelitian menunjukkan bahwa kecepatan angin pada Musim Barat sebesar 0,33 meter dan dominan ke arah Timur, sementara pada Musim Timur sebesar 0,91 meter dari arah Tenggara ke Barat Laut, serta pada Musim Peralihan (antara bulan Maret-Mei) adalah sebesar 1,08 meter dari arah Tenggara dan Timur. Pengaruh kecepatan angin tersebut terhadap gelombang laut di perairan Bitung dibahas dalam tulisan ini©

scholarly journals Wave Directions in a Narrow Bay

2010 ◽  
Vol 40 (1) ◽  
pp. 155-169 ◽  
Author(s):  
Heidi Pettersson ◽  
Kimmo K. Kahma ◽  
Laura Tuomi
Keyword(s):  
Wave Model ◽  
Wave Climate ◽  
Spectral Peak ◽  
Step Size ◽  
Weakly Nonlinear ◽  
Spectral Wave Model ◽  
Directional Coupling ◽  
Directional Wave ◽  
The Baltic ◽  
The Waves

Abstract In slanting fetch conditions the direction of actively growing waves is strongly controlled by the fetch geometry. The effect was found to be pronounced in the long and narrow Gulf of Finland in the Baltic Sea, where it significantly modifies the directional wave climate. Three models with different assumptions on the directional coupling between the wave components were used to analyze the physics responsible for the directional behavior of the waves in the gulf. The directionally decoupled model produced the direction at the spectral peak correctly when the slanting fetch geometry was narrow but gave a weaker steering than observed when the fetch geometry was broader. The method of Donelan estimated well the direction at the spectral peak in well-defined slanting fetch conditions, but overestimated the longer fetch components during wave growth from a more complex shoreline. Neither the decoupled nor the Donelan model reproduced the observed shifting of direction with the frequency. The performance of the third-generation spectral wave model (WAM) in estimating the wave directions was strongly dependent on the grid resolution of the model. The dominant wave directions were estimated satisfactorily when the grid-step size was dropped to 5 km in the gulf, which is 70 km in its narrowest part. A mechanism based on the weakly nonlinear interactions is proposed to explain the strong steering effect in slanting fetch conditions.

scholarly journals Automated power management strategy for wind power generation system using pitch angle controller

2019 ◽  
Vol 52 (3-4) ◽  
pp. 169-182 ◽  
Author(s):  
R Sitharthan ◽  
CK Sundarabalan ◽  
KR Devabalaji ◽  
T Yuvaraj ◽  
A Mohamed Imran
Keyword(s):  
Power Generation ◽  
Wind Power ◽  
Power Management ◽  
Control Strategy ◽  
Pitch Angle ◽  
Reactive Power ◽  
Research Work ◽  
Wind Power Generation ◽  
Generation System ◽  
Power Generation System

In this literature, a new automated control strategy has been developed to manage the power supply from the wind power generation system to the load. The main objective of this research work is to develop a fuzzy logic–based pitch angle control and to develop a static transfer switch to make power balance between the wind power generation system and the loads. The power management control system is a progression of logic expressions, designed based on generating power and load power requirement. The outcome of this work targets at an improved power production, active and reactive power compensation and ensures system load constraints. To validate the proposed control strategy, a detailed simulation study is carried out on a 9-MW wind farm simulation simulated in MATLAB/Simulink environment.

scholarly journals WAVES AT SEKONDI, GHANA

1966 ◽  
Vol 1 (10) ◽  
pp. 1 ◽  
Author(s):  
L. Draper
Keyword(s):  
Southern Hemisphere ◽  
Sea Waves ◽  
Severe Damage ◽  
Pressure Recording ◽  
Electric Wave ◽  
International Geophysical Year ◽  
Time Of Year ◽  
The Waves ◽  
Wave Recorder ◽  
International Geophysical

During the International Geophysical Year the National Institute of Oceanography in collaboration with Ghana IGY Committee and the Ghana Railway and Harbours Administration made recordings of sea waves at a point 2,300 feet off Sekondi point in a direction 156°. The instrument used was an N.I.O. piezo-electric wave recorder of the pressure recording type. Recordings started in June, 1958, and continued until the end of October that year when the cable suffered severe damage which could not easily be repaired. Because of the high cost of cable and the fact that a good series of records had already been obtained for a rough time of year, the instrument was recovered and used elsewhere. Records were taken every two hours and each has a useable length of twelve minutes. Most of the waves arriving at Sekondi are in the form of swell which has been generated by storms in the southern hemisphere; consequently wave conditions do not change very quickly, and it was found unnecessary to analyse every record except during rough conditions. The method of analysis used is that described in the associated paper "The Analysis and Presentation of Wave Data - a Plea for Uniformity".

scholarly journals Slope distribution in front-back asymmetric stochastic Lagrange time waves

2010 ◽  
Vol 42 (02) ◽  
pp. 489-508 ◽  
Author(s):  
G. Lindgren
Keyword(s):  
Particle Velocity ◽  
Random Fields ◽  
Wave Model ◽  
Linear Wave ◽  
Multivariate Normal ◽  
Ocean Engineering ◽  
Expected Number ◽  
Measuring Station ◽  
Predetermined Level ◽  
The Waves

The stochastic Lagrange wave model is a realistic alternative to the Gaussian linear wave model, which has been successfully used in ocean engineering for more than half a century. In this paper we present the slope distributions and other characteristic distributions at level crossings for asymmetric Lagrange time waves, i.e. what can be observed at a fixed measuring station, thereby extending results previously given for space waves. The distributions are given as expectations in a multivariate normal distribution, and they have to be evaluated by simulation or numerical integration. Interesting characteristic variables are the slope in time, the slope in space, and the vertical particle velocity when the waves are observed close to instances when the water level crosses a predetermined level. The theory has been made possible by recent generalizations of Rice's formula for the expected number of marked crossings in random fields.

scholarly journals A PARAMETRIC HURRICANE WAVE PREDICTION MODEL

1988 ◽  
Vol 1 (21) ◽  
pp. 82
Author(s):  
Ian R. Young
Keyword(s):  
Spatial Distribution ◽  
Radiative Transfer Equation ◽  
Synthetic Data ◽  
Wave Model ◽  
Limited Growth ◽  
Forward Movement ◽  
Spectral Wave Model ◽  
Wave Conditions ◽  
Two Parameters ◽  
The Waves

A spectral wave model based on a numerical solution of the Radiative Transfer Equation is used to create a synthetic data base on wave conditions within hurricanes. The results indicate that both the velocity of forward movement and maximum wind velocity within the storm play an important role in determining both the magnitude of the waves generated and also the spatial distribution of these waves. An equivalent fetch for hurricane wave generation which is a function of these two parameters is proposed. This concept, together with the standard JONSWAP fetch limited growth relationships, provide a simple means for estimating wave conditions within hurricanes.

The Track and Accompanying Sea Wave Forecasts of the Supertyphoon Mangkhut (2018) by a Real-Time Regional Forecast System

2020 ◽  
Vol 37 (11) ◽  
pp. 2075-2084
Author(s):  
Yuhang Zhu ◽  
Yineng Li ◽  
Shiqiu Peng
Keyword(s):  
Real Time ◽  
Large Scale ◽  
Negative Impact ◽  
Wave Model ◽  
Forecast Skill ◽  
Track Forecast ◽  
Sea Waves ◽  
Mean Error ◽  
Forecasting System ◽  
Sea Wave

AbstractThe track and accompanying sea wave forecasts of Typhoon Mangkhut (2018) by a real-time regional forecasting system are assessed in this study. The real-time regional forecasting system shows a good track forecast skill with a mean error of 69.9 km for the forecast period of 1–72 h. In particular, it predicted well the landfall location on the coastal island of South China with distance (time) biases of 76.89 km (3 h) averaging over all forecasting made during 1–72 h and only 3.55 km (1 h) for the forecasting initialized 27 h ahead of the landfall. The sea waves induced by Mangkhut (2018) were also predicted well by the wave model of the forecasting system with a mean error of 0.54 m and a mean correlation coefficient up to 0.94 for significant wave height. Results from sensitivity experiments show that the improvement of track forecasting skill for Mangkhut (2018) are mainly attributed to application of a scale-selective data assimilation scheme in the atmosphere model that helps to maintain a more realistic large-scale flow obtained from the GFS forecasts, whereas the air–sea coupling has slightly negative impact on the track forecast skill.

scholarly journals Slepian models for the stochastic shape of individual Lagrange sea waves

2006 ◽  
Vol 38 (02) ◽  
pp. 430-450 ◽  
Author(s):  
Georg Lindgren
Keyword(s):  
Water Waves ◽  
Gaussian Model ◽  
Wave Model ◽  
Realistic Model ◽  
Offshore Structures ◽  
Sea Waves ◽  
Vertical Movements ◽  
Stochastic Version ◽  
Physically Based ◽  
Gaussian Theory

Gaussian wave models have been successfully used since the early 1950s to describe the development of random sea waves, particularly as input to dynamic simulation of the safety of ships and offshore structures. A drawback of the Gaussian model is that it produces stochastically symmetric waves, which is an unrealistic feature and can lead to unconservative safety estimates. The Gaussian model describes the height of the sea surface at each point as a function of time and space. The Lagrange wave model describes the horizontal and vertical movements of individual water particles as functions of time and original location. This model is physically based, and a stochastic version has recently been advocated as a realistic model for asymmetric water waves. Since the stochastic Lagrange model treats both the vertical and the horizontal movements as Gaussian processes, it can be analysed using methods from the Gaussian theory. In this paper we present an analysis of the stochastic properties of the first-order stochastic Lagrange waves model, both as functions of time and as functions of space. A Slepian model for the description of the random shape of individual waves is also presented and analysed.

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