Flow Simulation Around a Rim-Driven Wind Turbine and in Its Wake

2013 ◽  
Author(s):  
Bryan E. Kaiser ◽  
Svetlana V. Poroseva ◽  
Michael A. Snider ◽  
Rob O. Hovsapian ◽  
Erick Johnson
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
Flow Simulation ◽  
Wind Farms ◽  
Sensitivity Study ◽  
Onshore Wind ◽  
Flow Simulations ◽  
Turbine Design ◽  
The Impact

A relatively high free stream wind velocity is required for conventional horizontal axis wind turbines (HAWTs) to generate power. This requirement significantly limits the area of land for viable onshore wind farm locations. To expand a potential for wind power generation and an area suitable for onshore wind farms, new wind turbine designs capable of wind energy harvesting at low wind speeds are currently in development. The aerodynamic characteristics of such wind turbines are notably different from industrial standards. The optimal wind farm layout for such turbines is also unknown. Accurate and reliable simulations of a flow around and behind a new wind turbine design should be conducted prior constructing a wind farm to determine optimal spacing of turbines on the farm. However, computations are expensive even for a flow around a single turbine. The goal of the current study is to determine a set of simulation parameters that allows one to conduct accurate and reliable simulations at a reasonable cost of computations. For this purpose, a sensitivity study on how the parameters variation influences the results of simulations is conducted. Specifically, the impact of a grid refinement, grid stretching, grid cell shape, and a choice of a turbulent model on the results of simulation of a flow around a mid-sized Rim Driven Wind Turbine (U.S. Patent 7399162) and in its near wake is analyzed. This wind turbine design was developed by Keuka Energy LLC. Since industry relies on commercial software for conducting flow simulations, STAR-CCM+ software [1] was used in our study. A choice of a turbulence model was made based on the results from our previous sensitivity study of flow simulations over a rotating disk [2].

Effect of Wind Turbine Noise on Workers' Sleep Disorder: A Case Study of Manjil Wind Farm in Northern Iran

2015 ◽  
Vol 14 (02) ◽  
pp. 1550020 ◽  
Author(s):  
Milad Abbasi ◽  
Mohammad Reza Monnazzam ◽  
SayedAbbolfazl Zakerian ◽  
Arsalan Yousefzadeh
Keyword(s):  
Wind Turbine ◽  
Sleep Disorder ◽  
Wind Turbines ◽  
Daytime Sleepiness ◽  
Wind Farm ◽  
Wind Farms ◽  
Sound Level ◽  
Wind Turbine Noise ◽  
The Impact

Noise from wind turbines is one of the most important factors affecting the health, welfare, and human sleep. This research was carried out to study the effect of wind turbine noise on workers' sleep disorder. For this, Manjil Wind Farm, because of the greater number of staff and turbines than other wind farms in Iran, was chosen as case study. A total number of 53 participants took part in this survey. They were classified into three groups of mechanics, security, and official. In this study, daytime sleepiness data of workers were gathered using Epworth Sleepiness Scales (ESS) was used to determine the level of daytime sleepiness among the workers. The 8-h equivalent sound level (LAeq,8h) was measured to determine the individuals' exposure at each occupational group. Finally, the effect of sound, age, and workers' experience on individuals' sleep disorder was analyzed through multiple regression analysis in the R software. The results showed that there was a positive and significant relationship between age, workers' experience, equivalent sound level, and the level of sleep disorder. When age is constant, sleep disorder will increase by 26% as per each 1 dB increase in equivalent sound level. In situations where equivalent sound level is constant, an increase of 17% in sleep disorder is occurred as per each year of work experience. Because of the difference in sound exposure in different occupational groups. The effect of noise in repairing group was about 6.5 times of official group and also 3.4 times of the security group. Sleep disorder effect caused by wind turbine noise in the security group is almost two times more than the official group. Unlike most studies on wind turbine noise that address the sleep disorder among inhabitants nearby wind farms, this study, for the first time in the world, examines the impact of wind turbine noise on sleep disorder of workers who are more closer to wind turbines and exposed to higher levels of noise. So despite all the good benefits of wind turbines, it can be stated that this technology has health risks for all those exposed to its sound. However, further research is needed to confirm the results of this study.

Mooring Analysis of a Dual-Spar Floating Wind Farm with a Shared Line

2021 ◽  
pp. 1-37
Author(s):  
Guodong Liang ◽  
Zhiyu Jiang ◽  
Karl O. Merz
Keyword(s):  
Wind Turbines ◽  
Wind Farm ◽  
Wind Farms ◽  
Sensitivity Study ◽  
Design Stage ◽  
Mooring Lines ◽  
Natural Period ◽  
Preliminary Design Stage ◽  
Decay Tests ◽  
Line Design

Abstract Wind farms with shared mooring lines have the potential to reduce mooring costs. However, such wind farms may encounter complex system dynamics because adjacent wind turbines are coupled. This paper presents an analysis of the shared mooring system with a focus on the system natural periods. We first apply Irvine's method to model both the shared line and the two-segment single lines. The response surface method is proposed to replace iterations of the catenary equations of the single lines, and a realistic single line design is presented for OC3 Hywind. Then, system linearization and eigenvalue analysis are performed for the wind farm consisting of two spar floating wind turbines, one shared line, and four single lines. The obtained natural periods and natural modes are verified by numerical free decay tests. Finally, a sensitivity study is carried out to investigate the influence of mooring properties. It is found that the shared line has a significant influence on the natural periods in the surge and sway modes. The natural periods in the surge and sway modes are also most sensitive to the mooring property variations. Two sway eigenmodes are identified, and the lower sway natural period varies between 23 s and 88 s in the sensitivity study. The present analysis method can be used to identify critical natural periods at the preliminary design stage of shared mooring systems.

Overview of Wind Turbine Field Failure Databases: A Discussion of the Requirements for an Analysis

2018 ◽  
Author(s):  
Roozbeh Bakhshi ◽  
Peter Sandborn
Keyword(s):  
Statistical Analysis ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farms ◽  
Onshore Wind ◽  
Failure Times ◽  
Reliability Parameters ◽  
Failure Data ◽  
Offshore Installations ◽  
Field Failure

With renewable energy and wind energy in particular becoming mainstream means of energy production, the reliability aspect of wind turbines and their sub-assemblies has become a topic of interest for owners and manufacturers of wind turbines. Operation and Maintenance (O&M) costs account for more than 25% of total costs of onshore wind projects and these costs are even higher for offshore installations. Effective management of O&M costs depends on accurate failure prediction for turbine sub-assemblies. There are numerous models that predict failure times and O&M costs of wind farms. All these models have inputs in the form of reliability parameters. These parameters are usually generated by researchers using field failure data. There are several databases that report the failure data of operating wind turbines and researches use these failure data to generate the reliability parameters through various methods of statistical analysis. However, in order to perform the statistical analysis or use the results of the analysis, one must understand the underlying assumptions of the database along with information about the wind turbine population in the database such as their power rating, age, etc. In this work, we analyze the relevant assumptions and discuss what information is required from a database in order to improve the statistical analysis on wind turbines’ failure data.

scholarly journals Floating Performance of a Composite Bucket Foundation with an Offshore Wind Tower during Transportation

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 882 ◽  
Author(s):  
Hongyan Ding ◽  
Zuntao Feng ◽  
Puyang Zhang ◽  
Conghuan Le ◽  
Yaohua Guo
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
Wind Farms ◽  
Interaction Force ◽  
Offshore Wind ◽  
Construction Technique ◽  
Bucket Foundation ◽  
Offshore Wind Turbines ◽  
One Step

The composite bucket foundation (CBF) for offshore wind turbines is the basis for a one-step integrated transportation and installation technique, which can be adapted to the construction and development needs of offshore wind farms due to its special structural form. To transport and install bucket foundations together with the upper portion of offshore wind turbines, a non-self-propelled integrated transportation and installation vessel was designed. In this paper, as the first stage of applying the proposed one-step integrated construction technique, the floating behavior during the transportation of CBF with a wind turbine tower for the Xiangshui wind farm in the Jiangsu province was monitored. The influences of speed, wave height, and wind on the floating behavior of the structure were studied. The results show that the roll and pitch angles remain close to level during the process of lifting and towing the wind turbine structure. In addition, the safety of the aircushion structure of the CBF was verified by analyzing the measurement results for the interaction force and the depth of the liquid within the bucket. The results of the three-DOF (degree of freedom) acceleration monitoring on the top of the test tower indicate that the wind turbine could meet the specified acceleration value limits during towing.

Floating Offshore Wind Turbines: Responses in a Seastate Pareto Optimal Designs and Economic Assessment

2008 ◽  
Author(s):  
Paul Sclavounos ◽  
Christopher Tracy ◽  
Sungho Lee
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
Wind Farms ◽  
Economic Assessment ◽  
Offshore Wind ◽  
Pareto Optimal ◽  
Mooring System ◽  
Floating Structure ◽  
Water Depths

Wind is the fastest growing renewable energy source, increasing at an annual rate of 25% with a worldwide installed capacity of 74 GW in 2007. The vast majority of wind power is generated from onshore wind farms. Their growth is however limited by the lack of inexpensive land near major population centers and the visual pollution caused by large wind turbines. Wind energy generated from offshore wind farms is the next frontier. Large sea areas with stronger and steadier winds are available for wind farm development and 5MW wind turbine towers located 20 miles from the coastline are invisible. Current offshore wind turbines are supported by monopoles driven into the seafloor at coastal sites a few miles from shore and in water depths of 10–15m. The primary impediment to their growth is visual pollution and the prohibitive cost of seafloor mounted monopoles in larger water depths. This paper presents a fully coupled dynamic analysis of floating wind turbines that enables a parametric design study of floating wind turbine concepts and mooring systems. Pareto optimal designs are presented that possess a favorable combination of nacelle acceleration, mooring system tension and displacement of the floating structure supporting a five megawatt wind turbine. All concepts are selected so that they float stably while in tow to the offshore wind farm site and prior to their connection to the mooring system. A fully coupled dynamic analysis is carried out of the wind turbine, floater and mooring system in wind and a sea state based on standard computer programs used by the offshore and wind industries. The results of the parametric study are designs that show Pareto fronts for mean square acceleration of the turbine versus key cost drivers for the offshore structure that include the weight of the floating structure and the static plus dynamic mooring line tension. Pareto optimal structures are generally either a narrow deep drafted spar, or a shallow drafted barge ballasted with concrete. The mooring systems include both tension leg and catenary mooring systems. In some of the designs, the RMS acceleration of the wind turbine nacelle can be as low as 0.03 g in a sea state with a significant wave height of ten meters and water depths of up to 200 meters. These structures meet design requirements while possessing a favorable combination of nacelle accleration, total mooring system tension and weight of the floating structure. Their economic assessment is also discussed drawing upon a recent financial analysis of a proposed offshore wind farm.

Progressive Drift of Moored Floating Wind Turbines in a Wind Farm: Improved Mooring Capacity Model

2011 ◽  
Author(s):  
Hideyuki Suzuki ◽  
Yu Kitahara ◽  
Yukinari Fukumoto
Keyword(s):  
Wind Turbine ◽  
Safety Factor ◽  
Wind Turbines ◽  
Wind Farm ◽  
Wind Farms ◽  
Floating Platform ◽  
Main Research ◽  
Electric Power Supply ◽  
Analysis And Design ◽  
Wide Range

A wide range of platform concepts have been investigated for a floating wind turbine. So far analysis and design of motion characteristics of the platform is main research concern. One key research area less focused is floating platform related risk. If the wind energy would be one of the major sources of electric power supply, wind farms which are comprised of large number of floating wind turbines must be deployed in the ocean. Wind turbines are relatively closely arranged in a wind farm. In such an arrangement, a wind turbine accidentally started drifting will have some possibility to collide with floater and moorings of neighboring moored floating wind turbines, and might initiate another drift which might cause progressive drifting of wind turbines. In the previous report, a scenario of progressive drifting of wind turbines was investigated and associated risk was formulated. Quantitative risk of several arrangements of wind farm was estimated. Effects of arrangement of wind turbines in a wind farm and safety factor used in the design of moorings is discussed. Probability of initial drift was evaluated analyzing past records of accidents and design of mooring. In this research, strength of mooring system was modeled more precisely and probabilistic model was developed considering aged deterioration. Risk of progressive drifting was evaluated and safety factor required to realize a acceptable risk of a wind farm was discussed.

Dynamic Simulation of a Wind Farm With Variable Speed Wind Turbines

2003 ◽  
Author(s):  
E. Muljadi ◽  
C. P. Butterfield
Keyword(s):  
Wind Turbine ◽  
Wind Power ◽  
Wind Turbines ◽  
Wind Farm ◽  
Reactive Power ◽  
Power Network ◽  
Variable Speed ◽  
Power Capacity ◽  
Advantages And Disadvantages ◽  
The Impact

Wind power generation has increased very rapidly in the past few years. The total U.S. wind power capacity by the end of 2001 was 4,260 megawatts. As wind power capacity increases, it becomes increasingly important to study the impact of wind farm output on the surrounding power networks. In this paper, we attempt to simulate a wind farm by including the properties of the wind turbine, the wind speed time series, the characteristics of surrounding power network, and reactive power compensation. Mechanical stress and fatigue load of the wind turbine components are beyond the scope this paper. The paper emphasizes the impact of the wind farms on the electrical side of the power network. A typical wind farm with variable speed wind turbines connected to an existing power grid is investigated. Different control strategies for feeding wind energy into the power network are investigated, and the advantages and disadvantages are presented.

scholarly journals A Study of the Impact of Pitch Misalignment on Wind Turbine Performance

Machines ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 8 ◽  
Author(s):  
Davide Astolfi
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Power Output ◽  
Wind Farm ◽  
Reactive Power ◽  
Power Production ◽  
Test Case ◽  
Before And After ◽  
Input Variables ◽  
The Impact

Pitch angle control is the most common means of adjusting the torque of wind turbines. The verification of its correct function and the optimization of its control are therefore very important for improving the efficiency of wind kinetic energy conversion. On these grounds, this work is devoted to studying the impact of pitch misalignment on wind turbine power production. A test case wind farm sited onshore, featuring five multi-megawatt wind turbines, was studied. On one wind turbine on the farm, a maximum pitch imbalance between the blades of 4.5 ° was detected; therefore, there was an intervention for recalibration. Operational data were available for assessing production improvement after the intervention. Due to the non-stationary conditions to which wind turbines are subjected, this is generally a non-trivial problem. In this work, a general method was formulated for studying this kind of problem: it is based on the study, before and after the upgrade, of the residuals between the measured power output and a reliable model of the power output itself. A careful formulation of the model is therefore crucial: in this work, an automatic feature selection algorithm based on stepwise multivariate regression was adopted, and it allows identification of the most meaningful input variables for a multivariate linear model whose target is the power of the wind turbine whose pitch has been recalibrated. This method can be useful, in general, for the study of wind turbine power upgrades, which have been recently spreading in the wind energy industry, and for the monitoring of wind turbine performances. For the test case of interest, the power of the recalibrated wind turbine is modeled as a linear function of the active and reactive power of the nearby wind turbines, and it is estimated that, after the intervention, the pitch recalibration provided a 5.5% improvement in the power production below rated power. Wind turbine practitioners, in general, should pay considerable attention to the pitch imbalance, because it increases loads and affects the residue lifetime; in particular, the results of this study indicate that severe pitch misalignment can heavily impact power production.

Progressive Drifting of Floating Wind Turbines in a Wind Farm

2009 ◽  
Author(s):  
Hideyuki Suzuki ◽  
Masaru Kurimoto ◽  
Yu Kitahara ◽  
Yukinari Fukumoto
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
Wind Farms ◽  
Floating Platform ◽  
Allowable Limit ◽  
Main Research ◽  
Analysis And Design ◽  
Floating Wind Turbine ◽  
Wide Range

A wide range of platform types have been investigated for a floating wind turbine. Most of the research projects on a floating wind turbine assume that a land based wind turbine is to be installed on a platform with minimum modification to reduce the overall cost. For this reason, allowable limit of a motion of wind turbine is limited to lower value, for example, five degrees for static inclination and one to two degrees for pitching motion. So far analysis and design of motion characteristics of the platform have been main research concern. One key research area less focused is floating platform related risk. If the wind energy would be one of the major sources of power supply, wind farms which are comprised of large number of floating wind turbines must be deployed in the ocean. Wind turbines will be closely spaced in a wind farm so that installation cost should be minimized. In such an arrangement, a wind turbine accidentally started drifting has some possibility to collide or contact with the moorings of neighboring wind turbines and might cause progressive drifting of wind turbines. This paper present investigation of scenario of progressive drifting of floating wind turbines and evaluate risk of the scenario. Quantitative risk of several arrangements of wind farms is estimated. Effect of arrangement of wind turbines in a wind farm and safety factor used in design moorings is discussed.

Development of wireless bird collision monitoring system using 0-3 piezoelectric composite sensor on wind turbine blades

2017 ◽  
Vol 29 (17) ◽  
pp. 3426-3435
Author(s):  
Sang-Hyeon Kang ◽  
Lae-Hyong Kang
Keyword(s):  
Wind Turbine ◽  
Monitoring System ◽  
Wind Turbines ◽  
Turbine Blades ◽  
Wind Farms ◽  
Clean Energy ◽  
Piezoelectric Composite ◽  
Collision Rate ◽  
Wind Turbine Blades ◽  
The Impact

Over the past several decades, wind turbines have been established as one of the promising renewable energy systems for safe and clean energy collection. In order to collect more energy efficiently, the size of wind turbines has been increased and many wind farms have been constructed. Wind farms generate lots of energy, but they cause several side effects, such as noise and a threat to wildlife. It is reported that the bird collision rate of a wind turbine ranges from 0.01 to 23 annually. It is more serious in the case of rare and endangered birds. In order to monitor the effect on birds in wind farms, researchers have developed remote sensing technology for a detection apparatus using heat and radar. In addition, paint color and other variables have been studied regarding their effects on the collision rate. However, the existing methods are passive ways to prevent bird collision or just monitor bird conditions. Therefore, in this study, we propose a bird collision monitoring system that can detect where the bird collision occurred, which will aid in rescuing the birds. If the wind turbine blade has its own ability to capture an impact signal, the impact location can be easily detected, and the birds can be rescued. For this purpose, piezoelectric paint was applied to the wind turbine blades used in this study. The piezoelectric paint is also known as 0-3 piezoelectric composite, which is composed of piezoelectric particles and polymer resin. It is sensitive to high-frequency signals such as impacts, so it is suitable for monitoring bird collision signals. In order to amplify and transmit the impact signal from the rotating blade to a stationary base, a wireless transmission device using a ZigBee module and signal conditioning circuit was also installed. Through lab-scale tests, it was confirmed that this bird collision monitoring system shows a 100% bird collision detection rate.

Sign in / Sign up

Export Citation Format

Share Document