نتایج جستجو برای: mean wind speed

تعداد نتایج: 846128  

2003
Bernhard Lange Hans-Peter Waldl Rebecca Barthelmie Algert Gil Guerrero Detlev Heinemann

The wind farm layout program FLaP (Farm Layout Program) estimates the wind speed at any point in a wind farm and the power output of the turbines. The ambient flow conditions and the properties of the turbines and the farm are used as input. The core of the program is an axis-symmetric wake model, describing the wake behind one rotor. Here an approach based on the simplified Reynolds equation w...

One of the main tasks of the control systems in the wind turbines is to maintain the power of the wind when its wind speed proceed its nominal value. Because the failure to maintain the power in its nominal value in the region of the turbine curve damages the turbine and increases the mechanical stress. This object is obtained by controlling the pitch angle in the third region of the turbine cu...

Journal: :جغرافیا و مخاطرات محیطی 0
حسین عابد فاطمه صحراییان پرویز رضایی

abstract in general, garmesh wind in rasht province increases the temperature by 9°c and reduces relative humidity by 47%. the direction of prevailing wind during the garmesh wind is southern and its average speed increases by 2 m/s to 5 m/s. the highest frequency of garmesh wind occurs at 09 and 12 utc in december and january. the occurrence of this phenomenon substantially increases the horiz...

2017
Dongran Song Jian Yang Mei Su Anfeng Liu Yao Liu Young Hoon Joo Frede Blaabjerg

Variable speed wind turbines (VSWTs) usually adopt a maximum power point tracking (MPPT) method to optimize energy capture performance. Nevertheless, obtained performance offered by different MPPT methods may be affected by the impact of wind turbine (WT)’s inertia and wind speed characteristics and it needs to be clarified. In this paper, the tip speed ratio (TSR) and optimal torque (OT) metho...

Journal: :international journal of smart electrical engineering 2012
shahram javadi zeinab hojjatinia

in this paper, a new approach is proposed in order to select an optimal membership function for inputs of wind speed prediction system. then using a fuzzy method and the stochastic characteristics of wind speed in the previous year, the wind speed modeling is performed and the wind speed for the future year will be predicted. in this proposed method, the average and the standard deviation of in...

2000
MICHIEL VAN DEN BROEKE

The interactions between the semi-annual oscillation (SAO), near-surface wind speed and cloudiness at seven Antarctic stations are described, as is how near-surface temperature is affected. A firmly established half-yearly wave, in both the mean annual cycle of wind speed and of cloudiness, was found at two stations with limited local disturbances: Halley and Faraday. Following a significant we...

2012
ERIC HOLT JUN WANG

The trends in wind speed at a typical wind turbine hub height (80 m) are analyzed using the North American Regional Reanalysis (NARR) dataset for 1979–2009. A method, assuming the wind profile in the lower boundary layer as power-law functions of altitude, is developed to invert the power exponent (in the power-law equation) from theNARRdata and to compute the following variables at 80 m that a...

2013
Károly Tar

The first part is the statistical structure of wind speed, i.e. the methods for determination of Weibull-distribution’s parameters, fitting of frequency distribution of daily and monthly mean wind speeds with the Weibull-distribution, estimation of frequency distributions of daily and monthly mean wind speeds with the Weibull-distribution at different heights. The second part includes the stati...

Journal: :Remote Sensing 2011
Charlotte B. Hasager Merete Badger Alfredo Peña Xiaoli Guo Larsén Ferhat Bingöl

Ocean winds in the Baltic Sea are expected to power many wind farms in the coming years. This study examines satellite Synthetic Aperture Radar (SAR) images from Envisat ASAR for mapping wind resources with high spatial resolution. Around 900 collocated pairs of wind speed from SAR wind maps and from 10 meteorological masts, established specifically for wind energy in the study area, are compar...

2010
N. Ebuchi

An example of sensor synergy of active and passive microwave instruments for observations of marine surface winds is demonstrated using data from the Advanced Earth Observing Satellite-II (ADEOS-II), which carried a Ku-band microwave scatterometer, SeaWinds, and the Advanced Microwave Scanning Radiometer (AMSR). Scalar wind speed observed by AMSR was evaluated by using wind speed observed by Se...

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