This research proposal suggests studying the optimal arrangement of floating offshore wind turbines (FOWT) in a wind farm to minimize costs and improve efficiency. The proposal notes that incoming waves interacting with FOWT structures produce scattered and radiated waves that can interfere destructively with ambient waves at certain points. Arranging FOWT at these intersection points could reduce wave-induced loads, allowing cheaper floating platforms and moorings. The proposal focuses on the semi-submersible 'Trifloater' design and using computational fluid dynamics to model wave interactions and determine an optimal arrangement that minimizes motion for large-scale FOWT arrays.
Calculating Wind Farm Production in Al-Shihabi (South Of Iraq) Using WASPIJERA Editor
The Wind Turbine farms are becoming popular in the renewable energy world. In this research, the Wind Atlas
Analysis and Application Program (WAsP) has been used to estimate wind power density in Al-Shihabi (south
of Iraq). All statistical operations on data series are obtained from Field data collected from the wind
measurement towers which installed by the Science and Technology Ministry at Kut city south of IRAQ at three
heights (10, 30, 50 m). The wind turbine selected for this study to be installed in the wind farm are Bonus-
300kw, 600kw The Annual Energy Production (AEP) has been calculate which varies between (746.990 -
759.446 MWH) at 30 m and it s varies between produced AEP (1.576 - 1.600 GWh) at 50 m ,this site classified
as ( class-1).
Current research on simulations of flaoting offshore wind turbinesRicardo Faerron Guzmán
The document summarizes research on simulations of floating offshore wind turbines conducted at the University of Stuttgart. It provides an overview of wind energy research and testing at the university. It also describes optimization of offshore wind turbine design through a project to qualify two innovative floating substructure designs. Wave tank testing was conducted on a scaled model of a floating triple-spar platform to validate simulations including aerodynamic and hydrodynamic models.
Simulation of Wind Power Dynamic for Electricity Production in Nassiriyah Dis...IOSR Journals
This document summarizes a study that simulated wind power dynamics for electricity production in Nassiriyah District, Iraq. The study measured wind speed data from 2010-2013 at 10m altitude and used this to mathematically model and predict important wind energy parameters. It found that the minimum altitude for feasible wind speed (≥5m/s) for power production was 44m for a friction coefficient of 3.0 and 32m for a friction coefficient of 4.0. Weibull distribution analysis showed that the percentage of days with mean wind speeds ≥5m/s increased with higher altitudes and friction coefficients, making wind energy more viable at greater heights.
IRJET Wind Data Estimation of Kolhapur District using Improved Hybrid Opt...IRJET Journal
This document compares wind data for Kolhapur district in India obtained from the iHOGA and NASA POWER software programs. The iHOGA program was developed in C++ for optimizing hybrid renewable energy systems, while NASA POWER provides satellite-derived data on renewable resources. Both programs estimate the average wind speed at various locations in Kolhapur. The results show that locations like Hatkangale, Karveer and Shirol have the highest average wind speeds of around 5.5-6 m/s based on both models. Locations like Chandhgad, Shahuwadi and Radhanagari showed the lowest speeds of around 4.5-5 m/s. In general, the results from both
The SAGAN mission proposes using a constellation of four microsatellites in a tetrahedral formation to study the impact of atmospheric waves, neutral forcing, and ionospheric currents on low and mid-latitude plasma structuring. The satellites would carry instruments to measure electric and magnetic fields, electron density, and ion composition. Maintaining the tetrahedral formation over multiple orbital planes would allow for spatial correlation measurements to understand plasma dynamics in the ionosphere. The proposed one to two year mission aims to advance understanding of ionospheric coupling processes.
The document is Karl Nilsson's doctoral thesis which uses numerical modeling to study wind turbine wakes and wake interactions. It summarizes the key findings of the research which included: 1) validating numerical simulations of the Lillgrund wind farm against power production data, 2) analyzing uncertainties in the rotor modeling approach, and 3) evaluating the impact of including a power controller in the simulations. The research provides insights into modeling wind farm flows and optimizing wind farm layouts.
Suitable Wind Turbine Selection using Evaluation of Wind Energy Potential in ...IJCI JOURNAL
Nowadays, low environmental impact of wind energy is attractive. This paper aims to investigate the wind-power production potential of sites in North of Iran. Analysis of the wind speed of one city in the province of MAZANDARAN which is located in north of Iran is performed in this paper. The class of this site is a class one wind power site and the annual average wind speed is 3.58 m/s. The power density of this site is 99 W/m2 at 50 m height. Wind speed data measured over a five-year period at a typical site on the north coast of Iran are presented. The annual wind speeds at different heights have been studied to make optimum selection of wind turbine installation among three commercial turbines
Analytic Model of Wind Disturbance Torque on Servo Tracking AntennaIJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
Calculating Wind Farm Production in Al-Shihabi (South Of Iraq) Using WASPIJERA Editor
The Wind Turbine farms are becoming popular in the renewable energy world. In this research, the Wind Atlas
Analysis and Application Program (WAsP) has been used to estimate wind power density in Al-Shihabi (south
of Iraq). All statistical operations on data series are obtained from Field data collected from the wind
measurement towers which installed by the Science and Technology Ministry at Kut city south of IRAQ at three
heights (10, 30, 50 m). The wind turbine selected for this study to be installed in the wind farm are Bonus-
300kw, 600kw The Annual Energy Production (AEP) has been calculate which varies between (746.990 -
759.446 MWH) at 30 m and it s varies between produced AEP (1.576 - 1.600 GWh) at 50 m ,this site classified
as ( class-1).
Current research on simulations of flaoting offshore wind turbinesRicardo Faerron Guzmán
The document summarizes research on simulations of floating offshore wind turbines conducted at the University of Stuttgart. It provides an overview of wind energy research and testing at the university. It also describes optimization of offshore wind turbine design through a project to qualify two innovative floating substructure designs. Wave tank testing was conducted on a scaled model of a floating triple-spar platform to validate simulations including aerodynamic and hydrodynamic models.
Simulation of Wind Power Dynamic for Electricity Production in Nassiriyah Dis...IOSR Journals
This document summarizes a study that simulated wind power dynamics for electricity production in Nassiriyah District, Iraq. The study measured wind speed data from 2010-2013 at 10m altitude and used this to mathematically model and predict important wind energy parameters. It found that the minimum altitude for feasible wind speed (≥5m/s) for power production was 44m for a friction coefficient of 3.0 and 32m for a friction coefficient of 4.0. Weibull distribution analysis showed that the percentage of days with mean wind speeds ≥5m/s increased with higher altitudes and friction coefficients, making wind energy more viable at greater heights.
IRJET Wind Data Estimation of Kolhapur District using Improved Hybrid Opt...IRJET Journal
This document compares wind data for Kolhapur district in India obtained from the iHOGA and NASA POWER software programs. The iHOGA program was developed in C++ for optimizing hybrid renewable energy systems, while NASA POWER provides satellite-derived data on renewable resources. Both programs estimate the average wind speed at various locations in Kolhapur. The results show that locations like Hatkangale, Karveer and Shirol have the highest average wind speeds of around 5.5-6 m/s based on both models. Locations like Chandhgad, Shahuwadi and Radhanagari showed the lowest speeds of around 4.5-5 m/s. In general, the results from both
The SAGAN mission proposes using a constellation of four microsatellites in a tetrahedral formation to study the impact of atmospheric waves, neutral forcing, and ionospheric currents on low and mid-latitude plasma structuring. The satellites would carry instruments to measure electric and magnetic fields, electron density, and ion composition. Maintaining the tetrahedral formation over multiple orbital planes would allow for spatial correlation measurements to understand plasma dynamics in the ionosphere. The proposed one to two year mission aims to advance understanding of ionospheric coupling processes.
The document is Karl Nilsson's doctoral thesis which uses numerical modeling to study wind turbine wakes and wake interactions. It summarizes the key findings of the research which included: 1) validating numerical simulations of the Lillgrund wind farm against power production data, 2) analyzing uncertainties in the rotor modeling approach, and 3) evaluating the impact of including a power controller in the simulations. The research provides insights into modeling wind farm flows and optimizing wind farm layouts.
Suitable Wind Turbine Selection using Evaluation of Wind Energy Potential in ...IJCI JOURNAL
Nowadays, low environmental impact of wind energy is attractive. This paper aims to investigate the wind-power production potential of sites in North of Iran. Analysis of the wind speed of one city in the province of MAZANDARAN which is located in north of Iran is performed in this paper. The class of this site is a class one wind power site and the annual average wind speed is 3.58 m/s. The power density of this site is 99 W/m2 at 50 m height. Wind speed data measured over a five-year period at a typical site on the north coast of Iran are presented. The annual wind speeds at different heights have been studied to make optimum selection of wind turbine installation among three commercial turbines
Analytic Model of Wind Disturbance Torque on Servo Tracking AntennaIJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
Nwtc turb sim workshop september 22 24, 2008- site specific modelsndkelley
1) The document describes several inflow turbulence models available in the TurbSim code developed by NREL, including models based on standard IEC conditions, smooth homogeneous terrain, specific wind farm sites, complex mountainous terrain, and a North American high plains site.
2) Comparisons of simulation results using the IEC, Great Plains, and NWTC models show differences in predicted blade loads, rotor torque, bending moments and tip deflections when applied to the NREL 5 MW reference turbine.
3) In particular, the Great Plains model including a low-level jet produced significantly higher loads and deflections compared to the standard IEC model, demonstrating the importance of using site-specific models.
1) This document summarizes a student's study on optimizing the shape and dimensions of a point absorber wave energy converter to improve power extraction.
2) The study evaluated three shapes - a cylinder, cylinder with hemispherical bottom (bullet), and cylinder with conical bottom (cone) - and determined the bullet shape with a 10m radius and 15m total vertical length was most efficient.
3) Accounting for viscous effects through computational fluid dynamics simulations reduced predicted power extraction by over 10% and shifted the optimal damper configuration for certain sea states.
This thesis studies the design optimization and modeling improvement of a point absorber wave energy converter. It evaluates three hull shapes (cylinder, bullet, cone) through frequency and time domain models to determine the most efficient design. It also develops two final models: Model 1 includes viscous drag forces more accurately, finding it can significantly decrease predicted power extraction. Model 2 assesses the impact of varying wave force position on the hull, but finds it provides little benefit computationally. The thesis aims to advance point absorber design and modeling.
This document summarizes a study on optimizing the hull shape and dimensions of a point absorber wave energy converter. The study aimed to derive an efficient design for the buoy and improve the physical modeling of the device's response to waves. Different shapes and dimensions were evaluated in a frequency domain model and the most efficient design was selected for further time domain modeling and analysis, which included parameterizing drag coefficients obtained from computational fluid dynamics simulations. The improved time domain model was validated against simulation results and found to increase the physical accuracy of modeling viscous effects.
The SpaceDrive Project - First Results on EMDrive and Mach-Effect ThrustersSérgio Sacani
Propellantless propulsion is believed to be the best option for interstellar travel. However, photon rockets or solar sails have thrusts so low that maybe only nano-scaled spacecraft may reach the next star within our lifetime using very high-power laser beams. Following into the footsteps of earlier breakthrough propulsion programs, we are investigating different concepts based on non-classical/revolutionary propulsion ideas that claim to be at least an order of magnitude more efficient in producing thrust compared to photon rockets. Our intention is to develop an excellent research infrastructure to test new ideas and measure thrusts and/or artefacts with high confidence to determine if a concept works and if it does how to scale it up. At present, we are focusing on two possible revolutionary concepts: The EMDrive and the Mach-Effect Thruster. The first concept uses microwaves in a truncated cone-shaped cavity that is claimed to produce thrust. Although it is not clear on which theoretical basis this can work, several experimental tests have been reported in the literature, which warrants a closer examination. The second concept is believed to generate mass fluctuations in a piezo-crystal stack that creates non-zero time-averaged thrusts. Here we are reporting first results of our improved thrust balance as well as EMDrive and Mach-Effect thruster models. Special attention is given to the investigation and identification of error sources that cause false thrust signals. Our results show that the magnetic interaction from not sufficiently shielded cables or thrusters are a major factor that needs to be taken into account for proper μN thrust measurements for these type of devices.
This document summarizes the feasibility study of the WindFloat technology, a three-legged floating foundation designed to support offshore wind turbines in water depths from 30-50 meters. Key advantages of the floating foundation include flexibility in site location, access to stronger wind resources further offshore, and simpler offshore installation procedures compared to fixed foundations. The design draws on offshore oil and gas platform technologies while accounting for the different requirements of wind turbines. Hydrodynamic analysis and testing were performed to understand platform motions under wave and wind loads. Coupling of aerodynamic and hydrodynamic models allows for a more accurate analysis of interactions between the turbine and floating platform.
Effect of wind turbine on tlp floating platform responseseSAT Journals
Abstract Ever increasing population of India demands high production of electrical energy which puts immense pressure on our limited stock of non-renewable sources of energy and makes us dependent over imports from foreign countries. The present study focuses on the innovative concept of renewable offshore wind energy wherein the hydrodynamic analysis of Tension Leg Platform (TLP) Floating Offshore Wind Turbine (FOWT) which supports 5MW wind turbine tower is carried out using ‘ANSYS Workbench 14.5’. The six degree responses of the structure are obtained in operational conditions considering rated wind velocity of 11.4m/s in an irregular wave environment. Two cases are mainly considered, the first-one with incident wave and wind combined action along 00 (case 1) and the second–one with incident wave and wind combined action along 450 (case 2). The effect of wind turbine on TLP responses is compared in between 10 different geometric models; 5 models (A’, B’, C’, D’, E’) considering only the TLP platform and 5 models (A, B, C, D, E) considering the same platforms along with wind turbine tower. It is observed that TLP FOWT has higher translational motions (surge, sway, and heave) as compared to rotational motions (roll, pitch, and yaw). The metacentric height improves drastically after adding weight to concrete ballast. Higher reserve buoyancy helps reduce surge, sway, roll and yaw. The direction of the incident wave and wind does not affect heave response and remains same when incident wave and wind acts at 00 or 450. Higher reserve buoyancy increases pitch response only when incident wave and wind is acting at 00 but the reverse effect is observed when incident wave and wind is acting at 450. Keywords: TLP, floating offshore wind turbine, hydrodynamic analysis.
Basis of Design of Offshore Wind Turbines by System DecompositionFranco Bontempi
ABSTRACT
Offshore wind turbines are relatively complex structural and mechanical systems located in a highly demanding environment. Boundary conditions are intrinsically time-variable and space-dependent, both as loads and as constraints. Furthermore, different structural configurations must be handled: in fact, one has to pass from complete functionality to rotor stop. In consideration to the fact that in Italy, the construction of offshore wind farms for power production is currently under consideration, the aim of this paper is to corroborate the basis of design of offshore wind turbines, as a support to the decision making, having as a specific objective the structural design of the structure. In doing so, a systemic decomposition of the
relevant elements, both physical related (e.g. the constituting parts) and due to the external conditions (that lead to the identification of the structural loads) is performed. A necessary
reference to the Codes and Standards is coherently given, to develop a sound basis of design.
The 4th International Conference on
Advances in Structural Engineering and Mechanics (ASEM'08)
Jeju, Korea, May 26-28, 2008
Dynamic Analysis of an Offshore Wind Turbine: Wind-Waves Nonlinear InteractionFranco Bontempi
An offshore wind turbine can be considered as a relatively complex structural system
since several environmental factors (e.g. wind and waves) affect its dynamic
behavior by generating both an active load and a resistant force to the structure’s
deformation induced by simultaneous actions. Besides the stochastic nature, also
their mutual interaction should be considered as nonlinear phenomena could be
crucial for optimal and cost-effective design. Another element of complexity lies in
the presence of different parts, each one with its peculiar features, whose mutual
interaction determines the overall dynamic response to non-stationary environmental
and service loads. These are the reasons why a proper and safe approach to the
analysis and design of offshore wind turbines requires a suitable technique for
carrying out a structural and performances decomposition along with the adoption of
advanced computation tools. In this work a finite element model for coupled windwaves
analysis is presented and the results of the dynamic behavior of a monopiletype
support structure for offshore wind turbine are shown.
MAE 586 Report of Wind Tunnel VAWT SimulationsObaida Mohammad
The document summarizes research on the power production of Savonius vertical axis wind turbines (VAWTs) through wind tunnel simulations. Key findings include: (1) VAWTs have less disruptive wake effects than horizontal axis wind turbines (HAWTs), allowing closer spacing and higher power density; (2) Counter-rotating VAWT configurations produced 10-100% greater power than individual turbines due to beneficial wake interactions; (3) Optimal VAWT configurations could potentially reduce land usage by 33-60% compared to HAWT farms.
A strategic wind form integration method to polluted distibuted system with s...IAEME Publication
This document summarizes a research paper that proposes a method for integrating wind farms into polluted distributed power systems using shunt capacitors. The key points are:
1) Wind power is an important renewable energy source that is increasingly being integrated into distributed power systems. However, integrating wind farms can be challenging due to issues like reactive power demand and current harmonics from non-linear loads.
2) The paper proposes using shunt capacitors to compensate for reactive power and current harmonics when integrating wind farms. This allows for reliable, efficient and unity power factor operation at the point of connection.
3) A mathematical model is described and simulation results are presented to validate the approach of using shunt compensation to
This document presents the design of a vertical axis wind turbine for highways in India. It begins with an introduction to the problem of poor lighting and accidents on highways at night. It then reviews literature on previous wind turbine designs for highways. The proposed design methodology is to design the machine layout and blades to optimally capture wind energy from passing vehicles. The expected outcomes are increased visibility and safety on highways through the use of wind turbines. The document provides dimensions and design considerations for the turbine based on previous research. It summarizes several referenced papers on vertical axis wind turbine designs.
This document provides a review of using plasmonic nano-antennas to harvest mid-infrared (MIR) energy from the environment to power nano air vehicles (NAVs). It discusses how NAVs have limited flight times due to battery capacity, and harvesting ambient MIR radiation emitted from the Earth's surface is a potential solution. The document reviews MIR rectennas that could convert this radiation to DC electricity for constant power. Potential applications for powering NAVs include civil security, disaster monitoring, and hazardous environment inspection. It also provides equations to estimate NAV flight times and ranges based on battery and design specifications.
Wind Turbine Power Generation: Response PredictionIOSR Journals
The worldwide interest has been increasing about wind energy for power generation purpose due to
continue increase in fuel cost and the need to have clean source of energy. Wind energy may enhance the power
generation capabilities and maximize its capacity factor, inurn participate in generating power at lower cost. It
has also been notice that renewable power generation through wind energy is also the fast growing energy
technology. The optimization of the efficiency of wind turbine is prudent to complete the conventional power
sources. Wind Turbine Power Generation (WTPG) is a complex phenomenon to understand since the real
process has depends upon the Wind Velocity and the relative turbine dimensions and the outside climatological
parameter like Wind Velocity (WV) nature of wind, etc. In this paper an effort has been made to develop a fuzzy
logic approach to predict an appropriate WTPG considering the WV, AD and Chord Length of Turbine Blades
(CLTB) as input parameters. The complexities of the parameters and the imprecision of linguistic expressions
are taken into consideration; the application combining linguistic variable to optimize WTPG under multiple
conditions is presented in this study.
Fatigue Life Assessment for Power Cables in Floating Offshore Wind TurbinesFranco Bontempi
https://www.mdpi.com/journal/energies/special_issues/Wave_Tidal_Wind_Converters
Abstract: In this paper, a procedure is proposed to determine the fatigue life of the electrical cable connected to a 5MWfloating offshore wind turbine, supported by a spar-buoy at a water depth of 320 m, by using a numerical approach that takes into account site-specific wave and wind characteristics.
The efect of the intensity and the simultaneous actions of waves and wind are investigated and the outcomes for specific cable configurations are shown. Finally, the fatigue life of the cable is
evaluated. All analyses have been carried out using the Ansys AQWA computational code, which is a commercial code for the numerical investigation of the dynamic response of floating and fixed marine structures under the combined action of wind, waves and current. Furthermore, this paper applies the FAST NREL numerical code for comparison with the ANSYS AQWA results.
Keywords: wind energy; floating offshore wind turbine; dynamic analysis; fatigue life assessment; flexible power cables.
Experimental study of magnus effect over an aircraft wingeSAT Journals
This document describes an experimental study of applying the Magnus effect to an aircraft wing to improve lift. The study proposes using a treadmill-like motion on the upper surface of an airfoil to increase the pressure difference and generate more lift with less drag. A prototype was designed and tested with a symmetrical airfoil, driving rollers on a belt via a motor. Calculations were done to determine belt length and velocity based on motor RPM and gear ratios. The goal was to extend the aerodynamic performance of conventional wings.
This document discusses the effects of wind and seismic loading on spires through finite element analysis. It summarizes the modeling and analysis of a 100m steel spire with varying diameters. Modal analysis was conducted in ETABS to determine natural frequencies and mode shapes, which were validated against empirical calculations. The spire was then analyzed under wind loads according to different wind zones and seismic loads for Zone V. Results showed shear forces and bending moments decreased with height and wind speed, with seismic loads being much lower. Stresses were found to be within permissible limits. While the spire was found safe under wind loads, further fatigue analysis is needed due to failures of similar structures from fatigue in the past.
Augmented Diffuser for Horizontal Axis Marine Current TurbineIAES-IJPEDS
The potential of renewable energy sources is enormous as they can make a
major contribution to the future of energy needs. The ocean has a great
potential to become a practicaland predictable energy source compared to
other energy resources such as solar, wind, and nuclear. It offers different
sources of energy which can be utilized namely wave, tidal, offshore wind,
thermal, and tidalcurrent. Among these sources, marine tidal current has
major advantages such as higher power availability and predictability. The
main objective of this research work is to design and develop a horizontal
axis marine current turbine (HAMCT) that suitable for operating within
Malaysian ocean, which has low speed current (0.5 – 1 m/s average). A
prototype of augmented diffuser 4-bladed HAMCT applying NACA 0014
was proposed in the current study. The turbine model has 0.666 m diameter,
and it was designed to produce as much as power from flowing water
current. Model was constructed and tested at Marine Technology Center
(MTC) in three conditions, namely, free tow testing, ducted tow testing, and
ducted diffuser tow testing in order to predict the power and efficiency of the
turbine system. The results showed that the application of duct was
significant to concentrate the flow and diffuser arrangement was effective
when it was placed behind of the rotor in this condition of low water current
speed. The maximum efficiency Cp obtained in the current system was 0.58.
This chapter discusses wind resource and site assessment for wind farm projects. It explains that accurate wind speed measurements are crucial for assessing the wind resource and financial viability of a project. On-site wind measurements should be taken for at least one full year using high-quality instruments like cup anemometers. Careful instrument selection, installation, calibration and data analysis are important to obtain reliable wind speed data that can then be used to model the spatial variation of wind across the site.
what is air borne wind energy system and how it is work and types of wind energy system history of air borne wind energy system mathematical calculation related to awes all are in this pdf
Wind energy is a promising energy source. Modern wind power industry officially started in 1979 in Denmark with a
turbine of few KW and its evaluation brought up to now, devices of which rated power is higher than 20 MW.
The size of wind turbine’s massively increased and their design achieved a common standard device: Horizontal axis,
Three blades, Upwind, Pitch controlled blades, Active yaw system.
Nwtc turb sim workshop september 22 24, 2008- site specific modelsndkelley
1) The document describes several inflow turbulence models available in the TurbSim code developed by NREL, including models based on standard IEC conditions, smooth homogeneous terrain, specific wind farm sites, complex mountainous terrain, and a North American high plains site.
2) Comparisons of simulation results using the IEC, Great Plains, and NWTC models show differences in predicted blade loads, rotor torque, bending moments and tip deflections when applied to the NREL 5 MW reference turbine.
3) In particular, the Great Plains model including a low-level jet produced significantly higher loads and deflections compared to the standard IEC model, demonstrating the importance of using site-specific models.
1) This document summarizes a student's study on optimizing the shape and dimensions of a point absorber wave energy converter to improve power extraction.
2) The study evaluated three shapes - a cylinder, cylinder with hemispherical bottom (bullet), and cylinder with conical bottom (cone) - and determined the bullet shape with a 10m radius and 15m total vertical length was most efficient.
3) Accounting for viscous effects through computational fluid dynamics simulations reduced predicted power extraction by over 10% and shifted the optimal damper configuration for certain sea states.
This thesis studies the design optimization and modeling improvement of a point absorber wave energy converter. It evaluates three hull shapes (cylinder, bullet, cone) through frequency and time domain models to determine the most efficient design. It also develops two final models: Model 1 includes viscous drag forces more accurately, finding it can significantly decrease predicted power extraction. Model 2 assesses the impact of varying wave force position on the hull, but finds it provides little benefit computationally. The thesis aims to advance point absorber design and modeling.
This document summarizes a study on optimizing the hull shape and dimensions of a point absorber wave energy converter. The study aimed to derive an efficient design for the buoy and improve the physical modeling of the device's response to waves. Different shapes and dimensions were evaluated in a frequency domain model and the most efficient design was selected for further time domain modeling and analysis, which included parameterizing drag coefficients obtained from computational fluid dynamics simulations. The improved time domain model was validated against simulation results and found to increase the physical accuracy of modeling viscous effects.
The SpaceDrive Project - First Results on EMDrive and Mach-Effect ThrustersSérgio Sacani
Propellantless propulsion is believed to be the best option for interstellar travel. However, photon rockets or solar sails have thrusts so low that maybe only nano-scaled spacecraft may reach the next star within our lifetime using very high-power laser beams. Following into the footsteps of earlier breakthrough propulsion programs, we are investigating different concepts based on non-classical/revolutionary propulsion ideas that claim to be at least an order of magnitude more efficient in producing thrust compared to photon rockets. Our intention is to develop an excellent research infrastructure to test new ideas and measure thrusts and/or artefacts with high confidence to determine if a concept works and if it does how to scale it up. At present, we are focusing on two possible revolutionary concepts: The EMDrive and the Mach-Effect Thruster. The first concept uses microwaves in a truncated cone-shaped cavity that is claimed to produce thrust. Although it is not clear on which theoretical basis this can work, several experimental tests have been reported in the literature, which warrants a closer examination. The second concept is believed to generate mass fluctuations in a piezo-crystal stack that creates non-zero time-averaged thrusts. Here we are reporting first results of our improved thrust balance as well as EMDrive and Mach-Effect thruster models. Special attention is given to the investigation and identification of error sources that cause false thrust signals. Our results show that the magnetic interaction from not sufficiently shielded cables or thrusters are a major factor that needs to be taken into account for proper μN thrust measurements for these type of devices.
This document summarizes the feasibility study of the WindFloat technology, a three-legged floating foundation designed to support offshore wind turbines in water depths from 30-50 meters. Key advantages of the floating foundation include flexibility in site location, access to stronger wind resources further offshore, and simpler offshore installation procedures compared to fixed foundations. The design draws on offshore oil and gas platform technologies while accounting for the different requirements of wind turbines. Hydrodynamic analysis and testing were performed to understand platform motions under wave and wind loads. Coupling of aerodynamic and hydrodynamic models allows for a more accurate analysis of interactions between the turbine and floating platform.
Effect of wind turbine on tlp floating platform responseseSAT Journals
Abstract Ever increasing population of India demands high production of electrical energy which puts immense pressure on our limited stock of non-renewable sources of energy and makes us dependent over imports from foreign countries. The present study focuses on the innovative concept of renewable offshore wind energy wherein the hydrodynamic analysis of Tension Leg Platform (TLP) Floating Offshore Wind Turbine (FOWT) which supports 5MW wind turbine tower is carried out using ‘ANSYS Workbench 14.5’. The six degree responses of the structure are obtained in operational conditions considering rated wind velocity of 11.4m/s in an irregular wave environment. Two cases are mainly considered, the first-one with incident wave and wind combined action along 00 (case 1) and the second–one with incident wave and wind combined action along 450 (case 2). The effect of wind turbine on TLP responses is compared in between 10 different geometric models; 5 models (A’, B’, C’, D’, E’) considering only the TLP platform and 5 models (A, B, C, D, E) considering the same platforms along with wind turbine tower. It is observed that TLP FOWT has higher translational motions (surge, sway, and heave) as compared to rotational motions (roll, pitch, and yaw). The metacentric height improves drastically after adding weight to concrete ballast. Higher reserve buoyancy helps reduce surge, sway, roll and yaw. The direction of the incident wave and wind does not affect heave response and remains same when incident wave and wind acts at 00 or 450. Higher reserve buoyancy increases pitch response only when incident wave and wind is acting at 00 but the reverse effect is observed when incident wave and wind is acting at 450. Keywords: TLP, floating offshore wind turbine, hydrodynamic analysis.
Basis of Design of Offshore Wind Turbines by System DecompositionFranco Bontempi
ABSTRACT
Offshore wind turbines are relatively complex structural and mechanical systems located in a highly demanding environment. Boundary conditions are intrinsically time-variable and space-dependent, both as loads and as constraints. Furthermore, different structural configurations must be handled: in fact, one has to pass from complete functionality to rotor stop. In consideration to the fact that in Italy, the construction of offshore wind farms for power production is currently under consideration, the aim of this paper is to corroborate the basis of design of offshore wind turbines, as a support to the decision making, having as a specific objective the structural design of the structure. In doing so, a systemic decomposition of the
relevant elements, both physical related (e.g. the constituting parts) and due to the external conditions (that lead to the identification of the structural loads) is performed. A necessary
reference to the Codes and Standards is coherently given, to develop a sound basis of design.
The 4th International Conference on
Advances in Structural Engineering and Mechanics (ASEM'08)
Jeju, Korea, May 26-28, 2008
Dynamic Analysis of an Offshore Wind Turbine: Wind-Waves Nonlinear InteractionFranco Bontempi
An offshore wind turbine can be considered as a relatively complex structural system
since several environmental factors (e.g. wind and waves) affect its dynamic
behavior by generating both an active load and a resistant force to the structure’s
deformation induced by simultaneous actions. Besides the stochastic nature, also
their mutual interaction should be considered as nonlinear phenomena could be
crucial for optimal and cost-effective design. Another element of complexity lies in
the presence of different parts, each one with its peculiar features, whose mutual
interaction determines the overall dynamic response to non-stationary environmental
and service loads. These are the reasons why a proper and safe approach to the
analysis and design of offshore wind turbines requires a suitable technique for
carrying out a structural and performances decomposition along with the adoption of
advanced computation tools. In this work a finite element model for coupled windwaves
analysis is presented and the results of the dynamic behavior of a monopiletype
support structure for offshore wind turbine are shown.
MAE 586 Report of Wind Tunnel VAWT SimulationsObaida Mohammad
The document summarizes research on the power production of Savonius vertical axis wind turbines (VAWTs) through wind tunnel simulations. Key findings include: (1) VAWTs have less disruptive wake effects than horizontal axis wind turbines (HAWTs), allowing closer spacing and higher power density; (2) Counter-rotating VAWT configurations produced 10-100% greater power than individual turbines due to beneficial wake interactions; (3) Optimal VAWT configurations could potentially reduce land usage by 33-60% compared to HAWT farms.
A strategic wind form integration method to polluted distibuted system with s...IAEME Publication
This document summarizes a research paper that proposes a method for integrating wind farms into polluted distributed power systems using shunt capacitors. The key points are:
1) Wind power is an important renewable energy source that is increasingly being integrated into distributed power systems. However, integrating wind farms can be challenging due to issues like reactive power demand and current harmonics from non-linear loads.
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This document presents the design of a vertical axis wind turbine for highways in India. It begins with an introduction to the problem of poor lighting and accidents on highways at night. It then reviews literature on previous wind turbine designs for highways. The proposed design methodology is to design the machine layout and blades to optimally capture wind energy from passing vehicles. The expected outcomes are increased visibility and safety on highways through the use of wind turbines. The document provides dimensions and design considerations for the turbine based on previous research. It summarizes several referenced papers on vertical axis wind turbine designs.
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Wind Turbine Power Generation: Response PredictionIOSR Journals
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technology. The optimization of the efficiency of wind turbine is prudent to complete the conventional power
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prototype of augmented diffuser 4-bladed HAMCT applying NACA 0014
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high cost of manufacturing, high requirement for installation and construction, economical consideration,etc. In the most recent works, low dissipation energy in mechanism, low cost, simplicity and high performance are highly regarded as environmentally friendly methods for wind energy extraction mechanisms. In the current study, we would like to introduce a new and efficient method to extract wind energy using airfoil linear wind generator(ALWG). ALWG is a new method that produces liner reciprocating motion via attached airfoils to a mover in a magnetic field in order to generate electricity.The most important advantage of ALWG is its simplicity and its compatibility to all wind situations that can be more controllable relative to ocean-based and also relative to LWG that become challengeable problem.
Airfoil linear wind generator (alwg) as a novel wind energy extraction approach
Azim's Research Proposal
1. Research Proposal on Optimal Arrangement of
Floating Offshore Wind Farm
Mohammad Azim Fikri Zakaria
MEng Mechanical Engineering
with Sustainable Energy Systems
University of Southampton
United Kingdom
Email: azim fikri23@yahoo.com
This is a summary page
Abstract—This report proposes a PhD research on Floating
Offshore Wind Turbine (FOWT). It was clear from literature that
study on dynamic analysis with coupling effect is sufficient and
supported by the deployment of 7MW Trifloater near Fukushima.
Hence, it is only natural that the next study should focus on
the implementation of FOWT for large scale wind farm. The
combination effect of ambient incident wave with scattered and
radiated waves when out of phase will create a contour of destruc-
tive intersection points. Placing a floating device on this point will
result in a reduction in wave induced motion. It is suggested that
an optimal farm arrangement can encourage this phenomena
created by the FOWT hence improving the overall performance
of the system. Floating platform and mooring/anchoring system
can be made cheaper.
I. INTRODUCTION
The rapid progress of offshore wind energy is now advanc-
ing to deep water but with the challenge of costly floating
platforms. Together with mass production, it is hypothesized
that a reduction in total cost for floating wind farm can utilize
the effect of close proximity hydrodynamic interaction. This
paper does not only propose a new study on optimal FOWT
arrangement but also presents the thought process that lead to
the concept.
A. Project Aim
To study the optimal arrangement of FOWT for large scale
application in terms of both cost and yield efficiency.
B. Objectives
1. Determine the hydrodynamic interaction effect by am-
bient incident and interaction waves (radiated and scattered
waves by arrays) on close proximity devices.
2. To identify the best arrangement of FOWT that minimises
wave induced motion with considerations from the first objec-
tive.
3. To compare the performance of optimal arrangement
established in this project with fixed bottom wind farm.
II. THOUGHT PROCESS
It was found out that the study on fully coupled dynamic
analysis is abundant with almost all possible approach and
considerations. The presence of conflicting drivers within the
design of FOWT requires a new way of reducing wave motion
without increasing the total costs. Taking from the concept
of Wave Energy Device (WED) farm arrangement, the idea
is to place the devices as such to encourage the creation of
destructive intersection points by ambient incident and arrays
interaction waves. For large regular arrays, these hydrody-
namic interaction effects are reinforced as more scattered
waves from several cylinders may arrived at a given point.
It is also decided that this research project will focus on the
Trifloater design for future integration with the Fukushima
project and the slightly better overall performance of the
concept.
III. METHODOLOGY
The simulation method proposed will use a similar under-
lying process as Kagemoto (1991) but with a much larger
implementation and taking into account aerodynamic contribu-
tion on the floating structure. Several complexities are pointed
out for example the possibility of dynamic destructive contour
due to floating structure translational motion. Trade-off study
is required to determine the best course of action between
reductions in downwind or wave induced motion with respect
to FOWT arrangement. The computational power required to
simulate large arrays of FOWT pose a potential difficulty
due to the large number of unknowns involved. Gantt chart
is included to ensure knowledge development and simulation
results can be obtained in a considerable time.
IV. CONCLUSION
A study on this research area will be beneficial for the
overall progression of this technology towards large scale
deployment in the future. Overall, more self-development is
required to determine the best simulation method in terms or
algorithm and numerical simulation. With the support of senior
researchers from University of Tokyo and joint industries,
research objectives will be achievable.
2. I. INTRODUCTION
Offshore wind is one of the renewable sources that are
becoming feasible and more reliable within the coming years.
In this paper, a study on optimal wind farm arrangement for
floating offshore wind turbine (FOWT) is proposed. The effect
of incoming incident waves on floating structure will produce
scattered and radiated waves. These interaction waves travel
and when in a certain phase with ambient incident waves,
caused a contour of destructive intersection points where wave
motion is minimal. It is therefore suggested that arrangement
of FOWT for a wind farm can be made to encourage this phe-
nomenon and located at these intersection points to minimise
load acting on them [1]. As a result, platform structure and
mooring/anchoring system can be made cheaper and hence
reduces the overall costs. The thought process of this concept
is explained in greater detail in the next section along with a
brief literature review on floating wind turbine designs.
II. LITERATURE REVIEW
A. Floating Wind Turbine
Vast portion of offshore wind resource is in the deep water
region where depth is generally deeper than 30 meters. This
open up more possibilities to other regions for wind energy
generation for example Japan with estimated potential value of
141GW [2]. Without noise or visual restriction, wind turbines
can operate at optimum configuration such that a higher Tip
Speed Ratio (TSR) can be used producing higher energy yield
with less load acting on the blades [3].
The structural viability of floating offshore structures have
been demonstrated by the oil and gas industry. This however
are made possible by their strong economic potential. For
the deployment of wind turbines on floating platforms, the
system must therefore be made cheaper for it to be market
effective. This is indeed a challenge as most of the total
costs are contributed by the floating mechanism which include
platform, mooring and anchoring systems. These components
made up an important role to the overall structure by providing
the buoyancy force needed and the dynamic stability [4].
Nevertheless, unlike the oil and gas rigs, the application of
wind farm allows the benefit of mass production for floating
offshore wind turbines. This will drive down price significantly
and from Musail (2004), if the floating mechanism can be
made at 25% of the total costs, then energy cost of $0.05/kWh
is possible [5].
Generally, there are 3 established design concepts for
FOWT which are Tension Leg Platform (TLP), Spar Buoy,
and Semi-Submersible Trifloater. A further description of
these designs as well as their strengths and weaknesses are
thoroughly discussed in many literatures [4] [6] [7]. Most of
these literatures refer to the importance of coupled tower-
platform dynamic analysis with respect to aero and hydro
induced motion. However, it was found out that research
within those area are too abundant with various approach
and considerations. It would be beneficial to focus research
on new areas that may add significant contribution to the
development of this technology. Hence in the next section,
the thought process that was undertaken which lead to this
research proposal are discussed in sufficient detail.
Fig. 1. Spar buoy(left) and TLP(right) [4].
Fig. 2. Trifloater [4].
B. Thought Process
In order to narrow down research field to a single area of
interest, it would be best to focus on one design concept which
has the highest potential. Although a lot of literatures are
available on this matter, it is still hard to determine the absolute
best design due to their tendency to be site specific and lack
of real-life data on operation and maintenance. However, it is
safe to say that the Trifloater system is slightly better in terms
of dynamic response and cost compared to the rest [6] [7] [8].
Due to this and the fact that the FOWT prototype deployed
near Fukushima is a Trifloater, it is decided that this research
project should focus on this design. Afterwards, attention was
given to the case of coupled tower-platform dynamic analysis
in order to identify any possible study. The dynamic response
contributed by wave, wind and sea current on the platform are
important to effectively simulate the whole system towards
actual offshore environment. Some of these are summarised
in Table 1.
3. TABLE I
SUMMARY ON SOME OF THE STUDIES CONDUCTED ON COUPLED DYNAMIC ANALYSIS
Paper Description Remarks
[9] Ruoyu Zhang (2012) conducted a coupled dynamic analysis in the
time and frequency domain. The influence of mooring to the overall
response of the system was also taken into account.
Finite element models were established and subjected to different
combinations of turbulent wind, constant current and irregular
waves. By achieving this, the ultimate and fatigue loads can be
determined and hence the feasibility of such design can be justified.
This is an important approach as the use of time domain analysis
allowed all subjected loads to be taken into account.
Meanwhile frequency domain only considers wave load.
[10] According to Waris (2012), the dynamic response of a floating
wind turbine depends on these several factors:
1. Aerodynamic and Hydrodynamic effects.
2. Restoring and Resonance effects.
3. Mooring effects and Control system.
Ishihara and Phuc (2007) investigated the importance of aero-
dynamic and hydrodynamic damping supported with water tank
experiment. Study on resonance effects were also conducted.
The use of linear model by them for mooring system and restoring
force however may be influential for a small floating platform with
large response. Here, linear relationship may no longer applies and
non-linearity needs to be considered.
In this paper, non-linear model was applied to both catenary and
tensioned moorings as well as the restoring force. Dynamic analysis
was done with coupled tower-platform-mooring.
It was found out that both the catenary and tensioned moorings has
similar dynamic response when levelised at the same magnitude.
More importantly, the effect of heaving plates with respect to
diameter were also investigated.
This was initially thought as a potential research study based on a
paper by Simon Lefebure (2012). At this point, research on control
system for FOWT might be beneficial.
More research studies on this area are available but will
not be discussed in much detail for simplicity. For example,
Jonkman (2011) conducted a fully coupled time domain dy-
namic analysis on the 3 FOWT design concepts [13]. There
may still be possible research interests within this area that
are not identified due to the lack of expertise in this matter.
But it is arguable that current literatures have covered most
of the essentials and what is most needed now are full scale
experiment data to support the simulation results.
From here onwards, it would be best to look back into
the fundamental problems of FOWT in order to identify the
complications that need to be solved. It is proven that the
deployment of FOWT in hope for better access to wind
resource comes with greater complexities and total costs.
Overall, the conflicting design drivers for a platform can be
summarised as in Figure 2 [11].
From the diagram, it is apparent that to minimise pitch and
avoid wave periods require an increase in vessel mass. This
is the case for spar buoy design where ballast weight is used
to shift the structure natural frequency and centre of gravity
to be below centre of buoyancy [6]. This however conflicts
with cost. It is also worth mentioning another conflicting
drivers which are the mooring and anchoring system. Pitch
and heave motion can be limited reliably with more moorings
and anchors but at the expense of high cost. Conclusion that
can be drawn here is that a different approach needs to be
considered where minimisation of structure motions can be
done at a lower cost and without conflicting each other.
At this point, not many areas within the Trifloater are
left unexplored. The comprehensive study on coupled tower-
platform-mooring dynamic response towards environmental
loads were done to the point that full scale test prototype
was deployed with enough confidence. Optimal studies on
components sizing or even wind turbine specifications can be
conducted in response to real test data obtained. But, a study
on this would not add a sense of originality to the knowledge
base of this field. This should rather be left for engineering
firms to develop the framework of design and construction
according to a specific site.
As dynamic and static analysis are now reaching substantial
amount for full scale prototype to be tested, the idea of
large floating wind farm deployment is within reach. Although
optimal arrangement of fixed bottom offshore wind turbines
are well established and implemented in various sites, the case
would be different for FOWT. Due to the presence of hydro-
dynamic interaction effect on floating structures, one cannot
assume that all the devices will behave in the same dynamic
manner for the whole farm. The loading would be different
for each individuals and hence total power output cannot be
simply proportional to the number of devices [12]. As the
case for Wave Energy Device (WED), optimal arrangement
is needed to prevent a reduction in energy extraction due to
wave force shadowing or destructive interactions. However,
this conditions would actually be useful for the case of FOWT.
Kagemoto (1991) studied the effects of scattered and radi-
ated waves (interaction waves from close proximity structures)
to the device of interest [1]. The presence of hydrodynamic
interaction as a result of incoming interaction waves and
ambient incident wave when in certain phase will create a
contour of destructive and constructive wave forms. As a
result, it would be beneficial to arrange floating structures to
either be on the destructive or constructive points depending on
the purpose of the device. Constructive for the case of WED,
whereas FOWT on the destructive points. In small numbers,
this effect will not bring major impact. However for larger
arrays, these hydrodynamic interaction effect are reinforced
due to the availability of more scattered waves from many
cylinders arriving at a given point [14].
4. Fig. 3. Conflicting design drivers [11].
The principle idea for this study is not new, but simulations
were simplistic even for WED which is the source idea for
this research project. For example, the simulation studies by
Kagemoto (1991) were only done on a basic cylinder struc-
ture with 2 maximum arrays consisting of 4 cylinders each.
Furthermore, the dynamic response of a FOWT is different
as the presence of high wind tower subjects the structure to
aerodynamic load. As a result, the coupling of aero and hydro
induced motion will produce a different response of scattered
and radiated waves. Hence the research interest proposed here
is to study the optimal arrangement of a floating wind farm
with interest on minimising the wave induced motion via
hydrodynamic interactions.
Fig. 4. Basic representation of hydrodynamic interaction resulted from
ambient incident and interaction waves (scattered and radiation).
III. METHODOLOGY
It was found out that resonance effects play a significant
role in large arrays causing enhanced hydrodynamic effect on
individual structures and large free surface elevations. These
bring serious implications for large arrays deployment and
hence it is important to understand how these effects occurred
and interact with other variables [14]. The initial methodol-
ogy proposed here will use the same underlying process of
Kagemoto (1991). First step would be to perform a simplified
simulation on heaving single cylinders (not triple columns as
of a Trifloater). The purpose is to determine how scattered and
radiated waves interact with ambient incident wave and how
these in turn affect other cylinders within the farm. Changes to
the overall performance of the system can then be identified.
Although this has been done by Kagemoto (1991), it is still
a crucial step as to verify the validity of simulation method
used in this research project. New information may also arise
and further improvements can be made according to current
technology.
Secondly, pitching and surging motion would be applied to
the cylinders in conjunction to the presence of aerodynamic
response to the wind turbine (unlike WED, pitching and
surging are assumed to be small). The effect of surging is
thought to have a significant impact as the FOWT would
then have the possibility to move out of the destructive points
identified from the simulation. It is assumed for now that the
destructive contour might be dynamic i.e. changing with time.
This would prove rather challenging to determine the optimal
contour and hence wind farm arrangement with respect to time.
A trade-off is probably required and to make sure that FOWT
would not be on the constructive points. The arrangement
should also consider the effect of downwind on the wind
turbines. Optimal positioning of devices with respect to wave
motion and wind conditions are hence needed. For example,
the positioning of the FOWT to reduce wave motion via
destructive intersections might cause a reduction in downwind.
Simulation will then proceed to actual Trifloater model.
Initially, a single isolated model should be studied first to de-
termine the Trifloater interaction waves charateristics produced
by the incoming incident wave. Note that real data from the
Fukushima FOWT prototype can be used to determine the
5. Fig. 5. Research timeframe.
scattered and radiated waves. Contour results obtained from
simulation can be compared to real data observations from
Fukushima Trifloater. Once validated, proceed to implementa-
tion of simulation method to multiple Trifloater as the case for
a wind Farm (e.g. 100 devices). Large arrays computation are
possible by conventional integral equation methods. However,
high computational power is still required simply because of
the large number of unknowns involved [14].
Later on, a comparison can be made between the optimal
arrangement produced in this project with the already estab-
lished offshore fixed bottom wind farm. The relevance of this
is that the performance of the derived FOWT arrangement can
be evaluated in terms of both cost and energy yield.
Indeed the methodology proposed here is still rudimentary
and more research studies are needed in terms of simulation
method i.e. numerical model or algorithm. Although both
Kagemoto (1991) and B.F.M Child (2010) presented in their
paper thorough numerical method for wave hydrodynamic
interaction, some of them require higher level of understanding
than just the standard linear wave and hydrodynamic theory
[12]. Also, the coupling effect of aerodynamic loading on
hydrodynamic interaction must be well understood. In general,
a time plan was drafted to assist in acquiring the required skills
and ensure research objectives can be achieved.
The Gantt chart provided here is only a rough idea of how
the research project will proceed. Plenty of time is allocated
at the beginning for knowledge and skills development. More
discussion with supervisors are needed for the overall progres-
sion of the project, simulations and field work data acquisition.
It is also worth mentioning that all the ideas put on here are
not mandatory and the writer is open to any suggestions given
by potential supervisors.
IV. CONCLUSION
As a conclusion, the aim of this research project is to study
the effect of hydrodynamic interaction on Trifloater FOWT
and the optimal arrangement for the implementation of a
wind farm. It is hypothesized that the presence of destructive
points as a result from these hydrodynamic interaction can
be beneficial for reducing induced wave motions on FOWT.
Although this concept has been introduced a long time ago
for all sorts of offshore industry, application on FOWT are
fairly new. Further considerations are needed for example on
pitching and surging effect from aerodynamic loading and
sea current. A study on this research area is believed to
be beneficial for the overall progression of this technology
towards large scale deployment in the future. Agreeably,
further understanding is still required namely on the numerical
and simulation method for this research project. An initial
time plan is given and with the possible support from senior
researchers from University of Tokyo and the joint industries
on this project, self-improvements can be made in order to
achieve the research objectives.
6. REFERENCES
[1] H. Kagemoto, Minimization of wave forces on an array of floating bodies
The inverse hydrodynamic interaction theory, Applied Ocean Research 14
(1991) 83-92, Elsevier Science 1991.
[2] Ishihara Web Page, Accessed October on 2015, Article: The chal-
lenge to the worlds first floating wind farm, Source: http://windeng.t.u-
tokyo.ac.jp/ishihara/e/.
[3] W. Musail, S. Butterfield, A. Boone, Feasibility of Floating Platform
Systems for Wind Turbines, NREL Conference Paper, 23rd ASME Wind
Energy Symposium, Nevada, January 2004.
[4] S. Butterfield, W. Musail, J. Jonkman, Engineering Challenges for
Floating Offshore Wind Turbines, NREL Conference Paper, Copenhagen
Offshore Wind Conference 2005.
[5] R. Pelc, R.M. Fujita, Renewable Energy from the Ocean, Marine Policy
26 (2002) 471-479, Elsevier.
[6] S. Lefebvre, M. Collu, Preliminary design of a floating support structure
for a 5MW offshore wind turbine, Ocean Engineering 40 (2012) 15-26
Elsevier.
[7] A.R. Henderson, M.B. Zaaijer, Floating windfarms for shallow offshore
sites, International Society of Offshore and Polar, The proceedings of the
14th International offshore and polar engineering conference 2004.
[8] C.S. Laura, D.C. Vicente, Life-cycle cost analysis of floating offshore
wind farms, Renewable Energy 66 (2014) 41-48 Elsevier.
[9] R. Zhang et Al. Dynamic response in frequency and time domains of
a floating foundation for offshore wind turbines, Ocean Engineering 60
(2013) 115-123 Elsevier.
[10] M.B. Waris, T. Ishihara, Dynamic response analysis of floating offshore
wind turbine with different types of heave plates and mooring systems by
using a fully nonlinear model, Coupled Systems Mechanics, Vol. 1, No.3
(2012).
[11] A.R. Henderson, D. Witcher, Floating offshore wind energy A review
of the current status and an assessment of the prospects, Wind Engineering,
The British Library 2010.
[12] B.F.M. Child, V. Venugopal, Optimal configurations of wave energy
device arrays, Ocean Engineering 37 (2010) 1402-1417 Elsevier.
[13] J.M. Jonkman, D. Matha, Dynamics of offshore floating wind turbines
analysis of three concepts, Wind Energy research article, Wiley Online
Library, January 2011.
[14] P. Mclver, ”Wave interaction with array of structures”, Review Article
on Applied Ocean Research 24 (2002)121-126 Elsevier.