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Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

0 Riso-R-434 Wind Speed and Direction  

E-Print Network [OSTI]

meteorological statistics for the area as it was considered a possible site for a nuclear power plant. \\ \\ Duringm I 0 Riso-R-434 t Wind Speed and Direction Changes due to Terrain Effects revealed-4000 Roskilde, Denmark May 1983 #12;RISĂ?-R-434 WIND SPEED AND DIRECTION CHANGES DUE TO TERRAIN EFFECTS

2

Design Wind Speed  

Science Journals Connector (OSTI)

Wind is characterized by various different parameters. They include the following items: (1) wind speed, such as the mean wind speed and maximum instantaneous wind speed; (2) wind direction such as the azimuth di...

Yozo Fujino; Kichiro Kimura; Hiroshi Tanaka

2012-01-01T23:59:59.000Z

3

Anemometer Data (Wind Speed, Direction) for Laurel, Nebraska (2001 - 2002)  

Open Energy Info (EERE)

Laurel, Nebraska (2001 - 2002) Laurel, Nebraska (2001 - 2002) Dataset Summary Description Wind data collected from Laurel, Nebraska from a 20-meter anemometer as part of the Western Area Power Administration anemometer loan program. Ten-minute average wind speed and direction is available for 2001 - 2002. The data was originally made available by Wind Powering America, a DOE Office of Energy Efficiency & Renewable Energy (EERE) program. A dynamic map displaying all available data from DOE anemometer loan programs is available http://www.windpoweringamerica.gov/anemometerloans/projects.asp. Source EERE Date Released November 09th, 2010 (4 years ago) Date Updated November 09th, 2010 (4 years ago) Keywords wind wind direction wind speed Data text/csv icon Jun 11, 2001 - Jul 1, 2001 (csv, 144 KiB)

4

Anemometer Data (Wind Speed, Direction) for Ugashik, AK (2001 - 2002) |  

Open Energy Info (EERE)

0 0 Varnish cache server Browse Upload data GDR 429 Throttled (bot load) Error 429 Throttled (bot load) Throttled (bot load) Guru Meditation: XID: 2142278290 Varnish cache server Anemometer Data (Wind Speed, Direction) for Ugashik, AK (2001 - 2002) Dataset Summary Description Wind data collected from Ugashik Traditional Village in Alaska from an anemometer as part of the Native American anemometer loan program. Monthly mean wind speed is available for 2001 through 2002, as is wind direction and turbulence data. Data is reported from a height of 20 m. The data was originally made available by Wind Powering America, a DOE Office of Energy Efficiency & Renewable Energy (EERE) program. A dynamic map displaying all available data from DOE anemometer loan programs is available http://www.windpoweringamerica.gov/anemometerloans/projects.asp.

5

Anemometer Data (Wind Speed, Direction) for Tanana, AK (2001 - 2002) |  

Open Energy Info (EERE)

40 40 Varnish cache server Anemometer Data (Wind Speed, Direction) for Tanana, AK (2001 - 2002) Dataset Summary Description Wind data collected from Tanana Village in Alaska from an anemometer as part of the Native American anemometer loan program. Monthly mean wind speed is available for 2001 through 2002, as is wind direction and turbulence data. Data is reported from a height of 20 m. The data was originally made available by Wind Powering America, a DOE Office of Energy Efficiency & Renewable Energy (EERE) program. A dynamic map displaying all available data from DOE anemometer loan programs is available http://www.windpoweringamerica.gov/anemometerloans/projects.asp. Source EERE Date Released November 09th, 2010 (4 years ago) Date Updated November 09th, 2010 (4 years ago)

6

A Technique for Deducing Wind Direction from Satellite Microwave Measurements of Wind Speed  

Science Journals Connector (OSTI)

A technique is presented to deduce wind direction from satellite microwave measurements of wind speed information. The technique, based on simple Ekman boundary layer dynamics, makes use of surface pressure fields routinely analyzed at the ...

Tsann-wang Yu

1987-09-01T23:59:59.000Z

7

Evaluation of NSCAT-2 Wind Vectors by Using Statistical Distributions of Wind Speeds and Directions  

Science Journals Connector (OSTI)

In order to validate wind vectors derived from the NASA scatterometer (NSCAT), statistical distributions of wind speeds and directions retrieved by the NSCAT- ... model function have been investigated by comparis...

Naoto Ebuchi

2000-04-01T23:59:59.000Z

8

Measurements of Wind Speed, Direction, and Vertical Profiles in an Evergreen Forest in Central Cambodia  

Science Journals Connector (OSTI)

The wind characteristics of speed, direction, and vertical profile were studied ... Thom Province, Cambodia. Three seasonal patterns of wind speeds and directions were identified. The first occurred ... , as well...

Koji Tamai; Akira Shimizu…

2007-01-01T23:59:59.000Z

9

Ris-R-Report Analysis of vertical wind direction and speed  

E-Print Network [OSTI]

Risø-R-Report Analysis of vertical wind direction and speed gradients for data from the met. mast Cariou, Rozenn Wagner, Julia Gottschall Title: Analysis of vertical wind direction and speed gradients. Finally, the direction shear was analysed as function of wind speed and compared to the corresponding

10

Characteristics of wind speed and wind direction in the atmospheric boundary layer on the southern coast of Bulgaria  

Science Journals Connector (OSTI)

The characteristics of wind speed and wind direction in the boundary atmospheric layer measured ... meteorological station. The sodar measurement data on wind parameters at different heights in different months ....

M. A. Novitskii; L. K. Kulizhnikova…

2012-03-01T23:59:59.000Z

11

SCALAR WIND SPEED AND DIRECTION TROPICAL CYCLONE RETRIEVALS FOR CONICAL SCANNING SCATTEROMETERS  

E-Print Network [OSTI]

SCALAR WIND SPEED AND DIRECTION TROPICAL CYCLONE RETRIEVALS FOR CONICAL SCANNING SCATTEROMETERS--Scatterometer measurements of ocean vector winds (OVW) are significantly degraded in the presence of the precipitation, especially in tropical cyclones. This paper presents a new ocean hurricane/typhoon wind vector retrieval

Hennon, Christopher C.

12

Anemometer Data (Wind Speed, Direction) for YKHC-Bethel, AK (2003 - 2004) |  

Open Energy Info (EERE)

YKHC-Bethel, AK (2003 - 2004) YKHC-Bethel, AK (2003 - 2004) Dataset Summary Description Wind data collected from YKHC - Bethel in Alaska from an anemometer as part of the Native American anemometer loan program. Monthly mean wind speed is available for 2003 through 2004, as is wind direction and turbulence data. Data is reported from a height of 20 m. The data was originally made available by Wind Powering America, a DOE Office of Energy Efficiency & Renewable Energy (EERE) program. A dynamic map displaying all available data from DOE anemometer loan programs is available http://www.windpoweringamerica.gov/anemometerloans/projects.asp. Source EERE Date Released November 09th, 2010 (4 years ago) Date Updated November 09th, 2010 (4 years ago) Keywords wind wind direction wind speed

13

Anemometer Data (Wind Speed, Direction) for Ugashik, AK (2001...  

Open Energy Info (EERE)

by Wind Powering America, a DOE Office of Energy Efficiency & Renewable Energy (EERE) program. A dynamic map displaying all available data from DOE anemometer loan programs...

14

Anemometer Data (Wind Speed, Direction) for Pascua Yaqui, AZ (2003 - 2004)  

Open Energy Info (EERE)

Pascua Yaqui, AZ (2003 - 2004) Pascua Yaqui, AZ (2003 - 2004) Dataset Summary Description Wind data collected from Pascua Yaqui Indian Reservation in Arizona from an anemometer as part of the Native American anemometer loan program. Monthly mean wind speed is available for 2003 through 2004, as is wind direction and turbulence data. Data is reported from a height of 20 m. The data was originally made available by Wind Powering America, a DOE Office of Energy Efficiency & Renewable Energy (EERE) program. A dynamic map displaying all available data from DOE anemometer loan programs is available http://www.windpoweringamerica.gov/anemometerloans/projects.asp. Source EERE Date Released December 02nd, 2010 (3 years ago) Date Updated December 02nd, 2010 (3 years ago) Keywords wind

15

Anemometer Data (Wind Speed, Direction) for Quinault #3, WA (2004 - 2005) |  

Open Energy Info (EERE)

Quinault #3, WA (2004 - 2005) Quinault #3, WA (2004 - 2005) Dataset Summary Description Wind data collected from Quinault Indian Reservation in Washington from an anemometer as part of the Native American anemometer loan program. Monthly mean wind speed is available for 2004 through 2005, as is wind direction and turbulence data. Data is reported from a height of 20 m. The data was originally made available by Wind Powering America, a DOE Office of Energy Efficiency & Renewable Energy (EERE) program. A dynamic map displaying all available data from DOE anemometer loan programs is available http://www.windpoweringamerica.gov/anemometerloans/projects.asp. Source EERE Date Released December 02nd, 2010 (4 years ago) Date Updated December 02nd, 2010 (4 years ago) Keywords wind

16

Manual and Semiautomated Wind Direction Editing for Use in the Generation of Synthetic Aperture Radar Wind Speed Imagery  

Science Journals Connector (OSTI)

Previous studies have demonstrated that satellite synthetic aperture radar (SAR) can be used as an accurate scatterometer, yielding wind speed fields with subkilometer resolution. This wind speed generation is only possible, however, if a ...

George S. Young; Todd D. Sikora; Nathaniel S. Winstead

2007-06-01T23:59:59.000Z

17

Estimation of the Design Wind Speed  

Science Journals Connector (OSTI)

The modern approach to the specification of the design wind speed favours the explicit format which directly presents the design value of the wind speed instead of hiding the value behind the product of the chara...

Michael Kasperski

2013-01-01T23:59:59.000Z

18

The effect of wind speed and direction and surrounding maize on hybrid ventilation in a dairy cow building in Denmark  

Science Journals Connector (OSTI)

Abstract This study evaluated the effect of wind speed and direction and surrounding maize field on the air exchange rate (ACH) and indoor air velocity in a dairy cow building with hybrid ventilation, which combined auto-controlled natural and partial mechanical pit ventilation. The standard k ? ? turbulence model and standard wall function were applied in CFD modeling with extension of capability to account for the aerodynamics effect of surrounding maize plant canopy in the wind domain by using user defined functions (UDF). This extended model was validated by on-site measured velocities and temperatures. A reasonably good agreement was found between simulated and measured results. The wind speed influenced ACH greatly while modeling the maize field had little effect on ACH with low wind speed. With wind speed of 3.86 m s?1 in validation case, modeling the maize field reduced total ACH by 24%, ACH via bottom openings on the sidewall by 89.7% and air speed measured upwind by 71%. The results revealed that the plant canopy had the most significant effect on ACH through the opening on the sidewall. With the variation of wind direction from 0° to 90°, the difference of ACH could be 60%.

L. Rong; D. Liu; E.F. Pedersen; G. Zhang

2015-01-01T23:59:59.000Z

19

Adaptive neuro-fuzzy evaluation of wind farm power production as function of wind speed and direction  

Science Journals Connector (OSTI)

Wind velocity assumes a critical part for measuring the power created by the wind turbines. Nonetheless, power production from wind has a few weaknesses. One significant issue is that wind is a discontinuous ener...

Dalibor Petkovi?; Shahaboddin Shamshirband…

2014-05-01T23:59:59.000Z

20

Forecasting Solar Wind Speeds  

E-Print Network [OSTI]

By explicitly taking into account effects of Alfven waves, I derive from a simple energetics argument a fundamental relation which predicts solar wind (SW) speeds in the vicinity of the earth from physical properties on the sun. Kojima et al. recently found from their observations that a ratio of surface magnetic field strength to an expansion factor of open magnetic flux tubes is a good indicator of the SW speed. I show by using the derived relation that this nice correlation is an evidence of the Alfven wave which accelerates SW in expanding flux tubes. The observations further require that fluctuation amplitudes of magnetic field lines at the surface should be almost universal in different coronal holes, which needs to be tested by future observations.

Takeru K. Suzuki

2006-02-03T23:59:59.000Z

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

wind speed | OpenEI  

Open Energy Info (EERE)

speed speed Dataset Summary Description GIS data for offshore wind speed (meters/second). Specified to Exclusive Economic Zones (EEZ).Wind resource based on NOAA blended sea winds and monthly wind speed at 30km resolution, using a 0.11 wind sheer to extrapolate 10m - 90m. Annual average >= 10 months of data, no nulls. Source National Renewable Energy Laboratory (NREL) Date Released Unknown Date Updated Unknown Keywords GIS global NOAA NREL offshore wind wind speed Data application/zip icon Download Shapefile (zip, 18.5 MiB) Quality Metrics Level of Review Some Review Comment Temporal and Spatial Coverage Frequency Time Period License License Other or unspecified, see optional comment below Comment Please cite NREL and NOAA Rate this dataset Usefulness of the metadata

22

OpenEI - wind speed  

Open Energy Info (EERE)

NREL GIS Data: Global NREL GIS Data: Global Offshore Wind http://en.openei.org/datasets/node/869 GIS data for offshore wind speed (meters/second).  Specified to Exclusive Economic Zones (EEZ).Wind resource based on NOAA blended sea winds and monthly wind speed at 30km resolution, using a 0.11 wind sheer to extrapolate 10m - 90m.  Annual average  >= 10 months of data, no nulls. License

Type of License:  Other (please specify below)

23

Wind speed estimation using multilayer perceptron  

Science Journals Connector (OSTI)

Abstract Wind speed knowledge is prerequisite in the siting of wind turbines. In consequence the wind energy use requires meticulous and specified knowledge of the wind characteristics at a location. This paper presents a method for determining the annual average wind speed at a complex terrain site by using neural networks, when only short term data are available for that site. This information is useful for preliminary calculations of the wind resource at a remote area having only a short time period of wind measurements measurement in a site. Artificial neural networks are useful for implementing non-linear process variables over time, and therefore are a useful tool for estimating the wind speed. The neural network used is multilayer perceptron with three layers and the supervised learning algorithm used is backpropagation. The inputs used in the neural network were wind speed and direction data from a single station, and the training patterns used correspond to sixty days data. The results obtained by simulating the annual average wind speed at the selected site based on data from nearby stations with correlation coefficients above 0.5 were satisfactory, compared with actual values. Reliable estimations were obtained, with errors below 6%.

Ramón Velo; Paz López; Francisco Maseda

2014-01-01T23:59:59.000Z

24

Forecasting wind speed financial return  

E-Print Network [OSTI]

The prediction of wind speed is very important when dealing with the production of energy through wind turbines. In this paper, we show a new nonparametric model, based on semi-Markov chains, to predict wind speed. Particularly we use an indexed semi-Markov model that has been shown to be able to reproduce accurately the statistical behavior of wind speed. The model is used to forecast, one step ahead, wind speed. In order to check the validity of the model we show, as indicator of goodness, the root mean square error and mean absolute error between real data and predicted ones. We also compare our forecasting results with those of a persistence model. At last, we show an application of the model to predict financial indicators like the Internal Rate of Return, Duration and Convexity.

D'Amico, Guglielmo; Prattico, Flavio

2013-01-01T23:59:59.000Z

25

Wind speed vertical distribution at Mt. Graham  

E-Print Network [OSTI]

The characterization of the wind speed vertical distribution V(h) is fundamental for an astronomical site for many different reasons: (1) the wind speed shear contributes to trigger optical turbulence in the whole troposphere, (2) a few of the astroclimatic parameters such as the wavefront coherence time (tau_0) depends directly on V(h), (3) the equivalent velocity V_0, controlling the frequency at which the adaptive optics systems have to run to work properly, depends on the vertical distribution of the wind speed and optical turbulence. Also, a too strong wind speed near the ground can introduce vibrations in the telescope structures. The wind speed at a precise pressure (200 hPa) has frequently been used to retrieve indications concerning the tau_0 and the frequency limits imposed to all instrumentation based on adaptive optics systems, but more recently it has been proved that V_200 (wind speed at 200 hPa) alone is not sufficient to provide exhaustive elements concerning this topic and that the vertical d...

Hagelin, S; Lascaux, F

2010-01-01T23:59:59.000Z

26

Surface wind speed distributions| Implications for climate and wind power.  

E-Print Network [OSTI]

?? Surface constituent and energy fluxes, and wind power depend non-linearly on wind speed and are sensitive to the tails of the wind distribution. Until… (more)

Capps, Scott Blair

2010-01-01T23:59:59.000Z

27

Directional Spectra of Wind-Generated Waves  

Science Journals Connector (OSTI)

...H. Hui From observations of wind and of water surface elevation...the directional spectrum of wind-generated waves on deep water...inversely proportional to the fourth power of the frequency , with the...clearly dependent on the ratio of wind speed to peak wave speed...

1985-01-01T23:59:59.000Z

28

Wind Speed Prediction Via Time Series Modeling.  

E-Print Network [OSTI]

??Projected construction of nearby wind farms motivates this study of statistical forecasting of wind speed, for which accurate prediction is critically important to the fluid… (more)

Alexander, Daniel

2009-01-01T23:59:59.000Z

29

Surface Wind Direction Variability  

Science Journals Connector (OSTI)

Common large shifts of wind direction in the weak-wind nocturnal boundary layer are poorly understood and are not adequately captured by numerical models and statistical parameterizations. The current study examines 15 datasets representing a ...

Larry Mahrt

2011-01-01T23:59:59.000Z

30

Wind speed vertical distribution at Mt Graham  

Science Journals Connector (OSTI)

......October 2010 research-article Papers Wind speed vertical distribution at Mt Graham...characterization of the vertical distribution of wind speed, V(h), is fundamental for an...many different reasons: (i) the wind speed shear contributes to trigger optical......

S. Hagelin; E. Masciadri; F. Lascaux

2010-10-01T23:59:59.000Z

31

Wind Speed Forecasting for Power System Operation  

E-Print Network [OSTI]

In order to support large-scale integration of wind power into current electric energy system, accurate wind speed forecasting is essential, because the high variation and limited predictability of wind pose profound challenges to the power system...

Zhu, Xinxin

2013-07-22T23:59:59.000Z

32

LIDAR Wind Speed Measurements of Evolving Wind Fields  

SciTech Connect (OSTI)

Light Detection and Ranging (LIDAR) systems are able to measure the speed of incoming wind before it interacts with a wind turbine rotor. These preview wind measurements can be used in feedforward control systems that are designed to reduce turbine loads. However, the degree to which such preview-based control techniques can reduce loads by reacting to turbulence depends on how accurately the incoming wind field can be measured. Past studies have assumed the validity of physicist G.I. Taylor's 1938 frozen turbulence hypothesis, which implies that turbulence remains unchanged as it advects downwind at the mean wind speed. With Taylor's hypothesis applied, the only source of wind speed measurement error is distortion caused by the LIDAR. This study introduces wind evolution, characterized by the longitudinal coherence of the wind, to LIDAR measurement simulations using the National Renewable Energy Laboratory's (NREL's) 5-megawatt turbine model to create a more realistic measurement model. A simple model of wind evolution was applied to a frozen wind field that was used in previous studies to investigate the effects of varying the intensity of wind evolution. LIDAR measurements were also evaluated using a large eddy simulation (LES) of a stable boundary layer that was provided by the National Center for Atmospheric Research. The LIDAR measurement scenario investigated consists of a hub-mounted LIDAR that scans a circle of points upwind of the turbine in order to estimate the wind speed component in the mean wind direction. Different combinations of the preview distance that is located upwind of the rotor and the radius of the scan circle were analyzed. It was found that the dominant source of measurement error for short preview distances is the detection of transverse and vertical wind speeds from the line-of-sight LIDAR measurement. It was discovered in previous studies that, in the absence of wind evolution, the dominant source of error for large preview distances is the spatial averaging caused by the LIDAR's sampling volume. However, by introducing wind evolution, the dominant source of error for large preview distances was found to be the coherence loss caused by evolving turbulence. Different measurement geometries were compared using the bandwidth for which the measurement coherence remained above 0.5 and also the area under the measurement coherence curve. Results showed that, by increasing the intensity of wind evolution, the measurement coherence decreases. Using the coherence bandwidth metric, the optimal preview distance for a fixed-scan radius remained almost constant for low and moderate amounts of wind evolution. For the wind field with the simple wind evolution model introduced, the optimal preview distance for a scan radius of 75% blade span (47.25 meters) was found to be 80 meters. Using the LES wind field, the optimal preview distance was 65 meters. When comparing scan geometries using the area under the coherence curve, results showed that, as the intensity of wind evolution increases, the optimal preview distance decreases.

Simley, E.; Pao, L. Y.; Kelley, N.; Jonkman, B.; Frehlich, R.

2012-01-01T23:59:59.000Z

33

Estimation of Wind Speed in Connection to a Wind Turbine  

E-Print Network [OSTI]

horizontal axis wind power plant with rated power 750 KW. The plant has a three bladed rotor and an automatic is shown in Figure 1 demand Drive train Generator Rotor Wind speed Power demand Grid Power Controller PitchEstimation of Wind Speed in Connection to a Wind Turbine X. Ma #3; , N. K. Poulsen #3; , H. Bindner

34

The parent wind speed distribution: Why Weibull?  

Science Journals Connector (OSTI)

Abstract Part 1: The Weibull distribution has been used for many years to fit parent wind data. It is a particularly good fit to mean wind speed data arising from a wind climate dominated by temperate depressions. This good fit is practically useful, but intellectually not very satisfactory, because the familiar or Forward Weibull distribution is a purely empirical construct and there have seemed to be no reasons, grounded in either atmospheric physics or probability theory, why wind speeds should conform to this model. This paper introduces another distribution, the Offset Elliptical Normal (OEN) model, which has some justification in terms of probability theory and appears to form a more plausible model for mean wind speeds. It is shown that, over the entire practical range from everyday values to 1:10,000 year extremes and beyond, this new distribution matches a Weibull distribution so closely, that the Weibull can be regarded as not just empirical, but as an effective surrogate for the new distribution. One Weibull distribution corresponds to a whole family of the new distribution. Part 2: The assumptions of Harris’ Offset Elliptical Normal (OEN) model are verified using direct vector analysis of hourly wind observations at two, widely separated UK stations. The Jenkinson–Lamb index is found not to be effective in separating UK wind observations by causal mechanism for individual analysis. Fitting to the marginal distributions of wind speed and direction is shown not to be practicable owing to the information on their joint action that has been lost. Instead, an optimisation methodology is used to fit multiple disjoint OEN models to the joint PDF of the observed wind vectors, without prior separation of the observations. For Marham, Norfolk, a single OEN is sufficient, but two is marginally better. For Tiree, Inner Hebrides, two disjoint \\{OENs\\} are sufficient, but three is marginally better. For Changi, Singapore, three disjoint \\{OENs\\} correspond well with the three seasonal climates (inter-monsoon, “wet” NE monsoon and “dry” SW monsoon). For Rome (Ciampino) the component that dominates in the upper tail is shown to include downbursts from thunderstorms or other strong convective events.

R. Ian Harris; Nicholas J. Cook

2014-01-01T23:59:59.000Z

35

Wind Speed Data Analysis using Wavelet Transform  

E-Print Network [OSTI]

Abstract—Renewable energy systems are becoming a topic of great interest and investment in the world. In recent years wind power generation has experienced a very fast development in the whole world. For planning and successful implementations of good wind power plant projects, wind potential measurements are required. In these projects, of great importance is the effective choice of the micro location for wind potential measurements, installation of the measurement station with the appropriate measuring equipment, its maintenance and analysis of the gained data on wind potential characteristics. In this paper, a wavelet transform has been applied to analyze the wind speed data in the context of insight in the characteristics of the wind and the selection of suitable locations that could be the subject of a wind farm construction. This approach shows that it can be a useful tool in investigation of wind potential. Keywords—Wind potential, Wind speed data, Wavelet transform.

S. Avdakovic; A. Lukac; A. Nuhanovic; M. Music

36

Heuristic correction of wind speed mesoscale models simulations for wind farms prospecting and micrositing  

Science Journals Connector (OSTI)

Abstract The distribution of surface-level wind speeds over a given area is important information that is related to several processes in wind farm prospecting, design and micrositing. This information is often obtained from simulations using mesoscale models that take variables from global models as starting points. Improved outputs from mesoscale models can lead to reduced error compared to real wind speeds in the study area if in situ wind speed measurements are available. In this paper, we present several techniques to correct surface wind speed simulations from mesoscale models using data from measuring stations in wind farms. Specifically, we propose different heuristic corrections of the outputs from mesoscale models by means of surface fitting between the Weibull parameters of the wind speed series (from the mesoscale model) and those from the measuring stations (real wind speed) in the wind farm. The proposed methodology has direct applications in wind farm design, site prospection and micrositing. The good performance of our method is evident in the more accurate surface wind speeds obtained from mesoscale models in two wind farm prospection sites in Spain, where several measuring towers are installed.

B. Saavedra-Moreno; S. Salcedo-Sanz; C. Casanova-Mateo; J.A. Portilla-Figueras; L. Prieto

2014-01-01T23:59:59.000Z

37

A method of micrositing of wind turbine on building roof-top by using joint distribution of wind speed and direction, and computational fluid dynamics  

Science Journals Connector (OSTI)

Urban wind turbines are recommended for installation on a building roof-top to capture more wind energy. It is critical to decide an exact location for the wind turbine installation on the roof-top area. ... this...

Bavuudorj Ovgor; Sang-Kwon Lee…

2012-12-01T23:59:59.000Z

38

Globally competitive variable-speed wind turbines  

SciTech Connect (OSTI)

This paper focuses on the design issues which must be addressed if variable-speed wind turbines are to compete in the global marketplace. The paper examines how component-specific design decisions must be made on a system level if an optimized system is to be the result. The relationships among the blades, the generator and the utility interface are considered in detail, using the conceptual design of a 12 kW variable-speed wind turbine (the AOC 8/12) as a running example. The turbine is based on a direct-drive variable-reluctance generator (VRG), a single- or three-phase utility interface as appropriate, and a three-bladed rotor with fixed pitch. A preliminary turbine specification is provided, along with candidate power-speed curves and annual energy output. This paper documents the continuing development and commercialization of this technology which is being taken from the proof-of-concept stage and is now headed for field testing.

Torrey, D.A. [Rensselaer Polytechnic Institute, Troy, NY (United States); Childs, S.E.; Johnson, B.; Carter, J. [Atlantic Orient Corp., Norwich, VT (United States)

1995-12-31T23:59:59.000Z

39

Wind: wind speed and wind power density maps at 10m and 50m above...  

Open Energy Info (EERE)

files of wind speed and wind power density at 10 and 50 m heights. Global data of offshore wind resource as generated by NASA's QuikSCAT SeaWinds scatterometer....

40

Wind: wind speed and wind power density GIS data at 10m and 50m...  

Open Energy Info (EERE)

files of wind speed and wind power density at 10 and 50 m heights. Global data of offshore wind resource as generated by NASA's QuikScat SeaWinds scatterometer....

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Statistics of the Wind-Speed Difference Between Points with Cross-Wind Separation  

Science Journals Connector (OSTI)

This note reports statistics of instantaneous wind-speed differences between pairs of points in the...z...= 2?3 m), but separated by large distances (ranging up to 70 m) along an axis transverse to the direction ...

J. D. Wilson

2013-01-01T23:59:59.000Z

42

LIDAR Wind Speed Measurements of Evolving Wind Fields  

SciTech Connect (OSTI)

Light Detection and Ranging (LIDAR) systems are able to measure the speed of incoming wind before it interacts with a wind turbine rotor. These preview wind measurements can be used in feedforward control systems designed to reduce turbine loads. However, the degree to which such preview-based control techniques can reduce loads by reacting to turbulence depends on how accurately the incoming wind field can be measured. Past studies have assumed Taylor's frozen turbulence hypothesis, which implies that turbulence remains unchanged as it advects downwind at the mean wind speed. With Taylor's hypothesis applied, the only source of wind speed measurement error is distortion caused by the LIDAR. This study introduces wind evolution, characterized by the longitudinal coherence of the wind, to LIDAR measurement simulations to create a more realistic measurement model. A simple model of wind evolution is applied to a frozen wind field used in previous studies to investigate the effects of varying the intensity of wind evolution. LIDAR measurements are also evaluated with a large eddy simulation of a stable boundary layer provided by the National Center for Atmospheric Research. Simulation results show the combined effects of LIDAR errors and wind evolution for realistic turbine-mounted LIDAR measurement scenarios.

Simley, E.; Pao, L. Y.

2012-07-01T23:59:59.000Z

43

Ris-R-1563(EN) ACCUWIND -Accurate Wind Speed  

E-Print Network [OSTI]

Risø-R-1563(EN) ACCUWIND - Accurate Wind Speed Measurements in Wind Energy Summary Report Troels (RIS�) Title: ACCUWIND ­ Accurate Wind Speed Measurements in Wind Energy ­ Summary Report Department speed measurement in wind energy. It is being applied in high numbers around the world for wind energy

44

Assessment of Wind Speed Dependent Prediction Error  

Science Journals Connector (OSTI)

The investigations in this chapter follow the idea that the prediction error quantitatively depends on the meteorological situation that has to be predicted. As a first approach the wind speed as a main indicator...

Dr. Matthias Lange; Dr. Ulrich Focken

2006-01-01T23:59:59.000Z

45

Sampling Wind Data for Mean Wind Speed Estimation  

Science Journals Connector (OSTI)

Two sampling techniques are applied to wind data at 3 h intervals for six stations in the Great Plains region in the United States in order to investigate the reduction in the number of data needed to estimate the mean wind speed. One-in-k ...

Mark Jong; Gary Thomann

1981-03-01T23:59:59.000Z

46

Unsafe at Any (Wind) Speed?  

Science Journals Connector (OSTI)

The goal of this research was to examine the relative safety and stability of stationary motor vehicles exposed to severe winds. The focus was on private passenger vehicles. 1) The behavior of two instrumented storm-chase vehicles that were ...

Thomas Schmidlin; Barbara Hammer; Paul King; Yuichi Ono; L. Scott Miller; Gregory Thumann

2002-12-01T23:59:59.000Z

47

Time Series Models to Simulate and Forecast Wind Speed and Wind Power  

Science Journals Connector (OSTI)

A general approach for modeling wind speed and wind power is described. Because wind power is a function of wind speed, the methodology is based on the development of a model of wind speed. Values of wind power are estimated by applying the ...

Barbara G. Brown; Richard W. Katz; Allan H. Murphy

1984-08-01T23:59:59.000Z

48

Ris-R-Report Comparison of NWP wind speeds and  

E-Print Network [OSTI]

for nuclear power plants, and for Risø, the site of the Danish nuclear research reactors now being Risø 5 German nuclear power plant sites 9 Brunsbüttel 9 Brokdorf 12 Krümmel 15 Obrigheim 18) of wind speed and direction has been compared to measurements for seven German sites for nuclear power

49

Pitch and torque control of variable speed wind turbines.  

E-Print Network [OSTI]

??In this thesis the torque, speed and pitch angle control of variable speed wind turbine is investigated. In particular, it concentrates on the extraction of… (more)

Kulka, Arkadiusz

2004-01-01T23:59:59.000Z

50

Extreme wind climate modeling of some locations in India for the specification of the design wind speed of structures  

Science Journals Connector (OSTI)

The wind load on a structure is proportional to the square of the wind speed. Extreme wind climate modeling should be required for specifying the design wind speed of structures. Extreme wind speeds for a storm t...

Arnab Sarkar; Navneet Kumar; Debojyoti Mitra

2014-06-01T23:59:59.000Z

51

Improving WRF-ARW Wind Speed Predictions using Genetic Programming  

Science Journals Connector (OSTI)

Numerical weather prediction models can produce wind speed forecasts at a very high space resolution. ... that GP is able to successfully downscale the wind speed predictions, reducing significantly the inherent ...

Giovanna Martinez-Arellano; Lars Nolle…

2012-01-01T23:59:59.000Z

52

Wind-Speed Undulations Over Swell: Field Experiment and Interpretation  

Science Journals Connector (OSTI)

Results of field measurements of the swell-induced undulation of the wind speed taken from a Black Sea platform are presented. The wind speed and its fluctuations were measured at several ... m above the mean sea...

Y. P. Soloviev; V. N. Kudryavtsev

2010-09-01T23:59:59.000Z

53

Solar cycle dependence of global distribution of solar wind speed  

Science Journals Connector (OSTI)

A review is given of observational results concerning the solar cycle dependence of the global structure of solar wind speed distribution during the years from 1973 to 1987. Since observations of solar wind speed

Masayoshi Kojima; Takakiyo Kakinuma

1990-08-01T23:59:59.000Z

54

Photosynthetic Rate of a Plant Community and Wind Speed  

Science Journals Connector (OSTI)

The previous chapter illustrated not only that wind speed affects the photosynthetic rate, but also that ... single leaves, may be affected by the wind speed. Thus, to uncover facts about the...

Kazutoshi Yabuki

2004-01-01T23:59:59.000Z

55

Multiscale prediction of wind speed and output power for the wind farm  

Science Journals Connector (OSTI)

This paper focuses on establishing the multiscale prediction models for wind speed and power in wind farm by the average wind speed collected from the history records. Each type ... the predictive values of outpu...

Xiaolan Wang; Hui LI

2012-05-01T23:59:59.000Z

56

Offshore wind speed and wind power characteristics for ten locations in Aegean and Ionian Seas  

Science Journals Connector (OSTI)

This paper utilizes wind speed data measured at 3 and 10 ... and Aegean Seas to understand the behaviour of wind and thereafter energy yield at these stations using 5 MW rated power offshore wind turbine. With wind

HARALAMBOS S BAGIORGAS; GIOULI MIHALAKAKOU…

2012-08-01T23:59:59.000Z

57

Robust STATCOM control for the stabilisation of fixed-speed wind turbines during low voltages  

E-Print Network [OSTI]

and rotor- speed instability and more so if the wind turbine is connected to a weak grid. To prevent is still being produced by squirrel-cage induction generators (SCIGs) which are directly connected to the grid and operate at an almost fixed-speed [3]. They are advantageous as wind generators for their low

Pota, Himanshu Roy

58

Using ADCP Background Sound Levels to Estimate Wind Speed  

Science Journals Connector (OSTI)

It is well known that ambient sound is generated by wind through the process of wave breaking and bubble injection. The resulting sound levels are highly correlated with wind speed and, even though the physical process is not fully understood, ...

Len Zedel

2001-11-01T23:59:59.000Z

59

Hi-Q Rotor - Low Wind Speed Technology  

SciTech Connect (OSTI)

The project objective was to optimize the performance of the Hi-Q Rotor. Early research funded by the California Energy Commission indicated the design might be advantageous over state-of-the-art turbines for collecting wind energy in low wind conditions. The Hi-Q Rotor is a new kind of rotor targeted for harvesting wind in Class 2, 3, and 4 sites, and has application in areas that are closer to cities, or 'load centers.' An advantage of the Hi-Q Rotor is that the rotor has non-conventional blade tips, producing less turbulence, and is quieter than standard wind turbine blades which is critical to the low-wind populated urban sites. Unlike state-of-the-art propeller type blades, the Hi-Q Rotor has six blades connected by end caps. In this phase of the research funded by DOE's Inventions and Innovation Program, the goal was to improve the current design by building a series of theoretical and numeric models, and composite prototypes to determine a best of class device. Development of the rotor was performed by aeronautical engineering and design firm, DARcorporation. From this investigation, an optimized design was determined and an 8-foot diameter, full-scale rotor was built and mounted using a Bergey LX-1 generator and furling system which were adapted to support the rotor. The Hi-Q Rotor was then tested side-by-side against the state-of-the-art Bergey XL-1 at the Alternative Energy Institute's Wind Test Center at West Texas State University for six weeks, and real time measurements of power generated were collected and compared. Early wind tunnel testing showed that the cut-in-speed of the Hi-Q rotor is much lower than a conventional tested HAWT enabling the Hi-Q Wind Turbine to begin collecting energy before a conventional HAWT has started spinning. Also, torque at low wind speeds for the Hi-Q Wind Turbine is higher than the tested conventional HAWT and enabled the wind turbine to generate power at lower wind speeds. Based on the data collected, the results of our first full-scale prototype wind turbine proved that higher energy can be captured at lower wind speeds with the new Hi-Q Rotor. The Hi-Q Rotor is almost 15% more productive than the Bergey from 6 m/s to 8 m/s, making it ideal in Class 3, 4, and 5 wind sites and has application in the critical and heretofore untapped areas that are closer to cities, 'load centers,' and may even be used directly in urban areas. The additional advantage of the Hi-Q Rotor's non-conventional blade tips, which eliminates most air turbulence, is noise reduction which makes it doubly ideal for populated urban areas. Hi-Q Products recommends one final stage of development to take the Hi-Q Rotor through Technology Readiness Levels 8-9. During this stage of development, the rotor will be redesigned to further increase efficiency, match the rotor to a more suitable generator, and lower the cost of manufacturing by redesigning the structure to allow for production in larger quantities at lower cost. Before taking the rotor to market and commercialization, it is necessary to further optimize the performance by finding a better generator and autofurling system, ones more suitable for lower wind speeds and rpms should be used in all future testing. The potential impact of this fully developed technology will be the expansion and proliferation of energy renewal into the heretofore untapped Class 2, 3, 4, and 5 Wind Sites, or the large underutilized sites where the wind speed is broken by physical features such as mountains, buildings, and trees. Market estimates by 2011, if low wind speed technology can be developed are well above: 13 million homes, 675,000 commercial buildings, 250,000 public facilities. Estimated commercial exploitation of the Hi-Q Rotor show potential increase in U.S. energy gained through the clean, renewable wind energy found in low and very low wind speed sites. This new energy source would greatly impact greenhouse emissions as well as the public sector's growing energy demands.

Todd E. Mills; Judy Tatum

2010-01-11T23:59:59.000Z

60

Estimation methods review and analysis of offshore extreme wind speeds and wind energy resources  

Science Journals Connector (OSTI)

Abstract Offshore wind resources are more abundant and stronger and they blow more consistently than land-based wind resources. While gale force winds are easier to hit on the sea, the strong wind vibration and wind loads may exert severe damage and shock to wind turbines and wind power grids, even resulting in power grid collapse. Thus, to develop offshore wind power, apart from accurate quantitative wind energy potential assessments, it is necessary to effectively estimate extreme wind speeds. Toward this purpose, this paper investigates the current status of extreme wind speeds and wind energy assessment from literature review. It turns out that much work on wind energy estimation has been performed, whereas relatively little research involves extreme wind speeds, the main challenge stemming from the limited availability of derived extreme winds. Then a GH method based on artificial intelligence optimization algorithms is developed to re-analyze future samples of extreme wind speeds. On the basis of the re-analyzed extreme samples, as well as the Generalized Extreme Value (GEV) and Gumbel models optimized by Cuckoo Search (CS) and Chaotic Particle Swarm Optimization (CPSO) algorithms, the potential risks of extreme wind speeds are conducted based on 23-year (1990–2012) historic wind speeds. Thus, in terms of wind speeds, a comprehensive estimation for offshore wind energy is initially implemented in Bohai Rim, China. The assessment shows that the study areas have high-strength wind power but are rarely subjected to extreme wind speeds, which implies that it is suitable for wind farm construction.

Jianzhou Wang; Shanshan Qin; Shiqiang Jin; Jie Wu

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

A comparison of wind speed shears for frontal and undisturbed synoptic conditions  

Science Journals Connector (OSTI)

Wind speed shear parameters derived from data collected at ... conditions (cold frontal passage), all undisturbed winds, undisturbed high winds, and undisturbed low winds. The exponential values of the wind speed

Ching-Ming Sheih

62

Improved methodology for design of low wind speed specific wind turbine blades  

Science Journals Connector (OSTI)

Abstract The majority of wind power is currently produced on high wind speed sites, and the standard design of wind turbine blades has evolved to be structurally efficient under these conditions. Recently, sites with lower quality wind resources have begun to be considered for new wind farms. This study confirms the expectation that the standard high wind speed design process results in less efficient structures when used for low wind speed conditions, and that a low wind speed specific design process is able to yield structural improvements. A comparative structural analysis of generic blades from high and low wind speed turbines quantifies the differences in structural performance between high and low wind speed blades, and indicates the ways in which the standard design process should be modified to suit a low wind speed specific design. An improved design method specifically for low wind speed blades is proposed, with more emphasis on stiffness than in the standard high wind speed design. The improved design process results in a lighter and cheaper blade than the conventionally designed one, whilst still fulfilling the design requirements.

R.H. Barnes; E.V. Morozov; K. Shankar

2015-01-01T23:59:59.000Z

63

Reliability models of wind farms considering wind speed correlation and WTG outage  

Science Journals Connector (OSTI)

Abstract Wind speed correlation and wind turbine generator (WTG) outage are two factors affecting the reliability model of wind farms, but they are not addressed simultaneously in the existing literature. Meanwhile, WTG outage is reported to be dependent with wind speed to some extent. Therefore, the extended reliability models of wind farms incorporating both of these two factors and the dependency between WTG outage and wind speed are proposed in this paper. To consider the uncertainties and dependencies of wind speed and WTG failure, Copula method is applied to simulate correlated random variables representing for wind speed and the number of failed WTG units. Moreover, the linear apportioning technique is used to create multistate reliability models of wind farms from hourly wind power models. A number of sensitivity analyses on the modified IEEE RTS with wind power are conducted to validate the proposed reliability models for generation adequacy assessment. Case studies show that the generation adequacy indices increase with the correlation of wind speed and WTG forced outage rate (FOR). It is meaningful to point out that the effect of dependency between wind speed and WTG FOR on generation adequacy is minimal when WTG outages are independent, but it will be substantially larger when WTG outages are highly dependent. The proposed multistate reliability models of wind farms provide foundation for the reliability assessment of power systems with wind power integrated.

Fan Chen; Fangxing Li; Zhinong Wei; Guoqiang Sun; Jun Li

2015-01-01T23:59:59.000Z

64

Ocean Wind Speed Climatology from Spaceborne SAR Imagery  

Science Journals Connector (OSTI)

Spaceborne synthetic aperture radar (SAR) imagery can make high-resolution (?500 m) ocean wind speed measurements. The authors anticipate reprocessing the full decade and a half of Radarsat-1 SAR imagery and generating a SAR wind speed archive. These data ...

Frank M. Monaldo; Xiaofeng Li; William G. Pichel; Christopher R. Jackson

2014-04-01T23:59:59.000Z

65

Atmospheric Circulation Effects on Wind Speed Variability at Turbine Height  

Science Journals Connector (OSTI)

Mean monthly wind speed at 70 m above ground level is investigated for 11 sites in Minnesota for the period 1995–2003. Wind speeds at these sites show significant spatial and temporal coherence, with prolonged periods of above- and below-normal ...

Katherine Klink

2007-04-01T23:59:59.000Z

66

Microsoft Word - wind direction vane1.doc  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Understanding Wind Direction And Making A Wind Vane Grade Levels: Kindergarten, 1, 2, and 3 Objectives: The students will learn how to construct a wind vane and understand the...

67

Wind: wind speed and wind power density maps at 10m and 50m above surface  

Open Energy Info (EERE)

maps at 10m and 50m above surface maps at 10m and 50m above surface and 0.25 degree resolution for global oceans from NREL Dataset Summary Description (Abstract): Raster GIS ASCII data files of wind speed and wind power density at 10 and 50 m heights. Global data of offshore wind resource as generated by NASA's QuikSCAT SeaWinds scatterometer. (Purpose): To provide information on the wind resource potential of offshore areas. Source NREL Date Released December 31st, 2005 (9 years ago) Date Updated November 01st, 2007 (7 years ago) Keywords GEF GIS NASA NREL SWERA UNEP wind Data application/zip icon Download Maps (zip, 36.3 MiB) Quality Metrics Level of Review Some Review Comment Temporal and Spatial Coverage Frequency Time Period 2000 - 2004 License License Other or unspecified, see optional comment below

68

Wind: wind speed and wind power density GIS data at 10m and 50m above  

Open Energy Info (EERE)

10m and 50m above 10m and 50m above surface and 0.25 degree resolution for global oceans from NREL Dataset Summary Description (Abstract): Raster GIS ASCII data files of wind speed and wind power density at 10 and 50 m heights. Global data of offshore wind resource as generated by NASA's QuikScat SeaWinds scatterometer. (Purpose): To provide information on the wind resource potential of offshore areas. Source NREL Date Released December 31st, 2005 (9 years ago) Date Updated November 01st, 2007 (7 years ago) Keywords GEF GIS NASA NREL ocean offshore QuikScat SWERA UNEP wind Data application/msword icon Download Documentation (doc, 53.8 KiB) application/zip icon Download Data (zip, 41 MiB) Quality Metrics Level of Review Some Review Comment Temporal and Spatial Coverage Frequency Time Period 01/01/2000 - 12/31/2004

69

United States Wind Resource Map: Annual Average Wind Speed at...  

Wind Powering America (EERE)

4.0 Source: Wind resource estimates developed by AWS Truepower, LLC for windNavigator . Web: http:www.windnavigator.com | http:www.awstruepower.com. Spatial resolution of wind...

70

Wind speed and power density analysis based on Weibull and Rayleigh distributions (a case study: Firouzkooh county of Iran)  

Science Journals Connector (OSTI)

Abstract The present study aimed to analyze the wind speed data of Firouzkooh region. For this purpose, the wind speed data for a 3-h period measuring over a 10-year period (2001–2010) were analyzed to calculate and estimate the wind power generation potential. Similar trends of the wind speeds were seen in different years where the highest and the lowest mean wind speeds belonged to May 2010 and June 2002, respectively. The diurnal wind speed analysis demonstrated that the fastest winds blew from 6 am to 3 pm. Weibull and Rayleigh distribution functions were applied to find out the best fitting tool to the wind speed data. Results showed that Weibull and Rayleigh distribution functions can fit the actual values of wind speed well with almost the same coefficient of determination value (R2) of 0.97. The average values of wind power based on mean and root mean cube speed approaches were 203 and 248 W m?2 year?1, respectively indicating that Firouzkooh region stands in class 4 (which is a suitable area for wind turbine establishment). Finally, wind rose diagram revealed that the prevailing wind direction falls in the sector between 180° and 270° clockwise from North.

S.H. Pishgar-Komleh; A. Keyhani; P. Sefeedpari

2015-01-01T23:59:59.000Z

71

wind direction | OpenEI  

Open Energy Info (EERE)

direction direction Dataset Summary Description Freedom Field is a not-for-profit organization formed to facilitate development and commercialization of renewable energy solutions. The organization has installed a variety of renewable energy generating technologies at their facility (located at Rock River Water Reclamation in Rockford, IL), with the intention of serving as a demonstration facility. The facility monitors data (at 5-minute intervals) from a weather station, 12.4 kW of PV panels (56 220-watt panels), a 10kW wind turbine (HAWT), a 1.2 kW wind turbine (VAWT), an absorption cooling system, and biogas burners. Source Freedom Field Date Released July 19th, 2011 (3 years ago) Date Updated Unknown Keywords biogas monitoring data PV radiance solar temperature

72

A study of wind-speed maxima near the surface over the south central United States  

E-Print Network [OSTI]

-1960) and the Oklahoma City radiosonde station data for the time period June, 1966 to May, 1967. They also showed that the higher the monthly, mean, wind speed, the more likely that the wind direction was from the south. Bonner (1968) states, "Strong early morning...) (Member) (Member) May 1973 ABSTRACT A Study of Wind-Speed Maxima near the Surface over the South Central United States (May 1973) Samuel K. Beckman, B. S. , Kansas State University Directed by: Professor Walter K. Henry Radiosonde and rawinsonde...

Beckman, Samuel Karl

2012-06-07T23:59:59.000Z

73

Bias Correction and Bayesian Model Averaging for Ensemble Forecasts of Surface Wind Direction  

Science Journals Connector (OSTI)

Wind direction is an angular variable, as opposed to weather quantities such as temperature, quantitative precipitation, or wind speed, which are linear variables. Consequently, traditional model output statistics and ensemble postprocessing ...

Le Bao; Tilmann Gneiting; Eric P. Grimit; Peter Guttorp; Adrian E. Raftery

2010-05-01T23:59:59.000Z

74

Wind Speeds at Heights Crucial for Wind Energy: Measurements and Verification of Forecasts  

Science Journals Connector (OSTI)

Wind speed measurements from one year from meteorological towers and wind turbines at heights between 20 and 250 m for various European sites are analyzed and are compared with operational short-term forecasts of the global ECMWF model. The ...

Susanne Drechsel; Georg J. Mayr; Jakob W. Messner; Reto Stauffer

2012-09-01T23:59:59.000Z

75

MODELLING THE VERTICAL WIND SPEED AND TURBULENCE INTENSITY PROFILES AT PROSPECTIVE OFFSHORE WIND FARM SITES  

E-Print Network [OSTI]

MODELLING THE VERTICAL WIND SPEED AND TURBULENCE INTENSITY PROFILES AT PROSPECTIVE OFFSHORE WIND for conditions important for offshore wind energy utilisation are compared and tested: Four models tested with data from the offshore field measurement Rødsand by extrapolating the measured 10 m wind

Heinemann, Detlev

76

Concentration of Atmospheric Radon and Wind Direction  

Science Journals Connector (OSTI)

... in Lisbon, near the sea, is therefore excellent to test any probable relationship between radon concentration and wind directions since only half the possible wind directions are continental ones, ... since only half the possible wind directions are continental ones, therefore corresponding probably to higher radon concentrations. In order to study any correlation, the concentration of ...

F. BARREIRA

1961-06-17T23:59:59.000Z

77

File:CV WindSpeed.pdf | Open Energy Information  

Open Energy Info (EERE)

WindSpeed.pdf WindSpeed.pdf Jump to: navigation, search File File history File usage Cape Verde-Map Summarizing Average Wind Speed (m/s) Size of this preview: 776 × 600 pixels. Full resolution ‎(1,650 × 1,275 pixels, file size: 246 KB, MIME type: application/pdf) Description Cape Verde-Map Summarizing Average Wind Speed (m/s) Sources ECOWAS Creation Date 2011/11/14 Coordinates 16.002082°, -24.013197° File history Click on a date/time to view the file as it appeared at that time. Date/Time Thumbnail Dimensions User Comment current 11:43, 14 November 2011 Thumbnail for version as of 11:43, 14 November 2011 1,650 × 1,275 (246 KB) STobin (Talk | contribs) You cannot overwrite this file. Edit this file using an external application (See the setup instructions for more information)

78

United States Wind Resource Map: Annual Average Wind Speed at...  

Wind Powering America (EERE)

5.5 5.0 4.5 4.0 < 4.0 Source: Wind resource estimates developed by AWS Truepower, LLC. Web: http:www.awstruepower.com. Map developed by NREL. Spatial resolution of wind...

79

A comparison between a hydro-wind plant and wind speed forecasting using ARIMA models  

Science Journals Connector (OSTI)

In this paper we will present a comparison between two options for harnessing wind power. We will first analyze the behaviour of a wind farm that goes to the electricity market having previously made a forecast of wind speed while accepting the deviation penalties that these may incur. Second we will study the possibility of the wind farm not going to the market individually but as part of a hydro-wind plant.

2014-01-01T23:59:59.000Z

80

The Influence of Wind Speed on Shallow Marine Cumulus Convection  

Science Journals Connector (OSTI)

The role of wind speed on shallow marine cumulus convection is explored using large-eddy simulations and concepts from bulk theory. Focusing on cases characteristic of the trades, the equilibrium trade wind layer is found to be deeper at stronger ...

Louise Nuijens; Bjorn Stevens

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Correcting Wind Speed Measurements for Site Obstructions  

Science Journals Connector (OSTI)

The effects of obstructions on winds measured by the 30 station FLOWS (FAA-Lincoln Laboratory Operational Weather Studies) mesonet and the 6 station FAA LLWAS (Low Level Wind Shear Alčrt System) near Memphis, TN in 1985 are analyzed. The slowing ...

Marilyn M. Wolfson; T. Theodore Fujita

1989-04-01T23:59:59.000Z

82

The Solar Wind Helium Abundance: Variation with Wind Speed and the Solar Cycle  

E-Print Network [OSTI]

The Solar Wind Helium Abundance: Variation with Wind Speed and the Solar Cycle Matthias R. Aellig Alamos National Lab., Los Alamos, NM 87545 Abstract We investigate the helium abundance in the solar wind of 1994 and early 2000 are analyzed. In agreement with similar work for previous solar cycles, we find

Richardson, John

83

Ris-PhD-Report Accounting for the speed shear in wind  

E-Print Network [OSTI]

Risø-PhD-Report Accounting for the speed shear in wind turbine power performance measurement Rozenn for the speed shear in wind turbine power performance measurement Division: Wind Energy Division Abstract the measurement of the wind speed at hub height and the air density to characterise the wind field in front

84

Variable speed wind turbine for maximum power capture using adaptive fuzzy integral sliding mode control  

Science Journals Connector (OSTI)

This paper presents a nonlinear control approach to variable speed wind turbine (VSWT) with a wind speed estimator. The dynamics of the wind turbine (WT) is derived from single ... has been considered for exact e...

Saravanakumar Rajendran…

2014-06-01T23:59:59.000Z

85

Variable-Speed Wind Generator System with Maximum Output Power Control  

Science Journals Connector (OSTI)

To achieve maximum output power from wind generator systems, the rotational speed of wind generators should be adjusted in real time according to natural wind speed. This chapter pays attention to an optimum rota...

Yoko Amano

2013-01-01T23:59:59.000Z

86

A wind speed retrieval algorithm by combining 6 and 10 GHz data from Advanced Microwave Scanning Radiometer: Wind speed inside hurricanes  

Science Journals Connector (OSTI)

A wind speed retrieval algorithm was developed using 6 and ... aboard AQUA, for the purpose of retrieving wind speed inside rainstorms, primarily hurricanes and typhoons. ... because the brightness temperature se...

Akira Shibata

2006-06-01T23:59:59.000Z

87

MEASUREMENT OF WIND SPEED FROM COOLING LAKE THERMAL IMAGERY  

SciTech Connect (OSTI)

The Savannah River National Laboratory (SRNL) collected thermal imagery and ground truth data at two commercial power plant cooling lakes to investigate the applicability of laboratory empirical correlations between surface heat flux and wind speed, and statistics derived from thermal imagery. SRNL demonstrated in a previous paper [1] that a linear relationship exists between the standard deviation of image temperature and surface heat flux. In this paper, SRNL will show that the skewness of the temperature distribution derived from cooling lake thermal images correlates with instantaneous wind speed measured at the same location. SRNL collected thermal imagery, surface meteorology and water temperatures from helicopters and boats at the Comanche Peak and H. B. Robinson nuclear power plant cooling lakes. SRNL found that decreasing skewness correlated with increasing wind speed, as was the case for the laboratory experiments. Simple linear and orthogonal regression models both explained about 50% of the variance in the skewness - wind speed plots. A nonlinear (logistic) regression model produced a better fit to the data, apparently because the thermal convection and resulting skewness are related to wind speed in a highly nonlinear way in nearly calm and in windy conditions.

Garrett, A; Robert Kurzeja, R; Eliel Villa-Aleman, E; Cary Tuckfield, C; Malcolm Pendergast, M

2009-01-20T23:59:59.000Z

88

ARE660 Wind Generator: Low Wind Speed Technology for Small Turbine Development  

SciTech Connect (OSTI)

This project is for the design of a wind turbine that can generate most or all of the net energy required for homes and small businesses in moderately windy areas. The purpose is to expand the current market for residential wind generators by providing cost effective power in a lower wind regime than current technology has made available, as well as reduce noise and improve reliability and safety. Robert W. Preus’ experience designing and/or maintaining residential wind generators of many configurations helped identify the need for an improved experience of safety for the consumer. Current small wind products have unreliable or no method of stopping the wind generator in fault or high wind conditions. Consumers and their neighbors do not want to hear their wind generators. In addition, with current technology, only sites with unusually high wind speeds provide payback times that are acceptable for the on-grid user. Abundant Renewable Energy’s (ARE) basic original concept for the ARE660 was a combination of a stall controlled variable speed small wind generator and automatic fail safe furling for shutdown. The stall control for a small wind generator is not novel, but has not been developed for a variable speed application with a permanent magnet alternator (PMA). The fail safe furling approach for shutdown has not been used to our knowledge.

Robert W. Preus; DOE Project Officer - Keith Bennett

2008-04-23T23:59:59.000Z

89

CONSTRAINING HIGH-SPEED WINDS IN EXOPLANET ATMOSPHERES THROUGH OBSERVATIONS OF ANOMALOUS DOPPLER SHIFTS DURING TRANSIT  

SciTech Connect (OSTI)

Three-dimensional (3D) dynamical models of hot Jupiter atmospheres predict very strong wind speeds. For tidally locked hot Jupiters, winds at high altitude in the planet's atmosphere advect heat from the day side to the cooler night side of the planet. Net wind speeds on the order of 1-10 km s{sup -1} directed towards the night side of the planet are predicted at mbar pressures, which is the approximate pressure level probed by transmission spectroscopy. These winds should result in an observed blueshift of spectral lines in transmission on the order of the wind speed. Indeed, Snellen et al. recently observed a 2 {+-} 1 km s{sup -1} blueshift of CO transmission features for HD 209458b, which has been interpreted as a detection of the day-to-night (substellar to anti-stellar) winds that have been predicted by 3D atmospheric dynamics modeling. Here, we present the results of a coupled 3D atmospheric dynamics and transmission spectrum model, which predicts the Doppler-shifted spectrum of a hot Jupiter during transit resulting from winds in the planet's atmosphere. We explore four different models for the hot Jupiter atmosphere using different prescriptions for atmospheric drag via interaction with planetary magnetic fields. We find that models with no magnetic drag produce net Doppler blueshifts in the transmission spectrum of {approx}2 km s{sup -1} and that lower Doppler shifts of {approx}1 km s{sup -1} are found for the higher drag cases, results consistent with-but not yet strongly constrained by-the Snellen et al. measurement. We additionally explore the possibility of recovering the average terminator wind speed as a function of altitude by measuring Doppler shifts of individual spectral lines and spatially resolving wind speeds across the leading and trailing terminators during ingress and egress.

Miller-Ricci Kempton, Eliza [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Rauscher, Emily, E-mail: ekempton@ucolick.org [Lunar and Planetary Laboratory, University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721 (United States)

2012-06-01T23:59:59.000Z

90

Full scale experimental analysis of extreme coherent gust with wind direction changes (EOD)  

Science Journals Connector (OSTI)

A coherent wind speed and wind direction change (ECD) load case is defined in the wind turbine standard. This load case is an essential extreme load case that e.g. may be design driving for flap defection of active stall controlled wind turbines. The present analysis identifies statistically the magnitudes of a joint gust event defined by a simultaneously wind speed- and direction change in order to obtain an indication of the validity of the magnitudes specified in the IEC code. The analysis relates to pre-specified recurrence periods and is based on full-scale wind field measurements. The wind speed gust amplitude, occurring simultaneously with a wind direction change, corresponds well to the recommended ECD value of 15 m/s, except for the complex terrain case, where estimated extreme wind speed gust amplitudes are seen to exceed the IEC value with approximately 50%. The estimated extreme wind direction gust amplitudes associated with the investigated European sites are low compared to the recommended IEC- values. However, these values, as function of the mean wind speed, are difficult to validate thoroughly due to the limited number of fully correlated measurements.

K S Hansen; G C Larsen

2007-01-01T23:59:59.000Z

91

Blandford MTA Tower Wind Monitoring This document provides information not repeated in the monthly wind monitoring  

E-Print Network [OSTI]

on a regular basis. The logger samples wind speed and direction once every two seconds. These are then combined applicable): wind speed, wind speed standard deviation, wind direction, temperature, and solar insolation. F1 ranges applied for high and low wind speeds. A wind direction standard Blandford MTA Tower Wind

Massachusetts at Amherst, University of

92

Marion Meteorological Tower Wind Monitoring This document provides information not repeated in the monthly wind monitoring  

E-Print Network [OSTI]

. The logger samples wind speed and direction once every two seconds. These are then combined into 10-minute): wind speed, wind speed standard deviation, wind direction, temperature, and solar insolation. F1 > TF1 applied for high and low wind speeds. A wind direction standard Marion Met Tower Wind Monitoring #12

Massachusetts at Amherst, University of

93

Estimated changes in wind speed and wind power density over the western High Plains, 1971–2000  

Science Journals Connector (OSTI)

This manuscript presents the results of research on the temporal patterns in wind speed and wind power density from 1971 to 2000. The ... Mountains in an area which has a proven wind power resource. Policies and ...

J. Scott Greene; Matthew Chatelain; Mark Morrissey…

2012-08-01T23:59:59.000Z

94

Short term wind speed estimation in Saudi Arabia  

Science Journals Connector (OSTI)

Abstract In this paper, three methods are used for the prediction of wind speed, 12 h ahead, based on 72 h previous wind speed values at three locations viz. Rawdat Bin Habbas (inland north), Juaymah (east coast), and Dhulom (inland western region) in Saudi Arabia. These methods are Particle Swarm Optimization (PSO), Abductory Induction Mechanism (AIM), and the Persistence (PER) model. The available data at each site was divided into three consecutive groups. The first 50% was used for training, the second 25% for validation, and the remaining 25% for testing. The validation data set was used to select the network architecture and other user defined parameters. The testing data was used only to assess the performance of the networks on future unseen data that has not been used for training or model selection. For each of the three methods, each of 12 networks was trained to produce the wind speed at one of the next 12 h. Relatively, Close agreements were found between the predicted and measured hourly mean wind speed for all three locations with coefficient of correlation R2 values between 81.7% and 98.0% for PSO, between 79.8% and 98.5% for AIM and between 59.5% and 88.4% for persistence model. Both PSO and AIM methods underestimated WS values during most hours with an average value of 0.036 m/s and 0.02 m/s, respectively. However, persistence model overestimated the WS by an average value of 0.51 m/s. It is shown that the two developed models outperformed the persistence model on predicting wind speed 12 h ahead of time with slight advantage to the PSO method.

Mohamed Ahmed Mohandes; Shafiqur Rehman

2014-01-01T23:59:59.000Z

95

Prediction of wind speed profiles for short-term forecasting in the offshore environment R.J. Barthelmie and G. Giebel  

E-Print Network [OSTI]

in the forecast wind speed/power output might be anticipated using a directional rather than a constant bias for the calibration phase. A further advantage is that statistical techniques can predict power output directly rather than having to take the additional step of predicting power output from wind speed through the power

96

Standardization of raw wind speed data under complex terrain conditions: A data-driven scheme  

Science Journals Connector (OSTI)

Abstract Direct usage of raw wind data without modification of topographic and/or terrain effects may result in remarkable errors. Thus, standardization of raw wind datasets is of great importance to remove these influences. But, the existing standardization methods are mainly applicable for flat terrains, which may become inappropriate under complex terrain conditions. This paper presents a data-driven standardization scheme which can be applied for different terrains including complex terrains. Although this scheme is established based on wind profile records at a reference station equipped with both an anemometer at a near-ground height and a Doppler radar profiler system, it can be used for the standardization of surface winds not only at the reference station but also at other surrounding stations with only surface observation instruments. Thus, the proposed data-driven scheme is efficient and economic. As applications of this scheme, correction factors to convert raw wind speeds at about 50 weather stations in Hong Kong to those over a reference terrain are estimated. To verify the effectiveness of the proposed standardization scheme, a wind tunnel testing involved the topographic model of a weather station has been conducted. The standardization results via the proposed scheme and the wind tunnel testing are in good agreement. The proposed methodology and relevant results can be used for the analysis of topographic effects on wind speeds over complex terrains.

Y.C. He; P.W. Chan; Q.S. Li

2014-01-01T23:59:59.000Z

97

Wind Speed Retrieval Based on Sea Surface Roughness Measurements from Spaceborne Microwave Radiometers  

Science Journals Connector (OSTI)

Wind speed is the main factor responsible for the increase in ocean thermal emission because sea surface emissivity strongly depends on surface roughness. An alternative approach to estimate the surface wind speed (SWS) as a function of surface ...

Sungwook Hong; Inchul Shin

2013-02-01T23:59:59.000Z

98

Comparison of Two ARMA-GARCH Approaches for Forecasting the Mean and Volatility of Wind Speed  

Science Journals Connector (OSTI)

In this study, we develop two ARMA-GARCH models for predicting the mean and volatility of wind speed. The first model employs the standalone ARMA-GARCH model for modeling the mean wind speed and the variance simu...

Ergin Erdem; Jing Shi; Ying She

2014-01-01T23:59:59.000Z

99

Development of All-fiber Coherent Doppler Lidar to Measure Atmosphere Wind Speed  

Science Journals Connector (OSTI)

An all-fiber pulsed coherent Doppler lidar is developed to measure wind profiles. The maximum horizontal and vertical range for wind speed is 4.2km and 2km with speed accuracy of...

Liu, Jiqiao; Chen, Weibiao; Zhu, Xiaopeng

100

United States- Land Based and Offshore Annual Average Wind Speed at 100 Meters  

Broader source: Energy.gov [DOE]

Full-size, high resolution version of the 100-meter land-based and offshore wind speed resource map.

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Wind Direct Ltd | Open Energy Information  

Open Energy Info (EERE)

Wind Direct Ltd Wind Direct Ltd Place Solihull, United Kingdom Zip B91 2PQ Sector Wind energy Product Develops small wind farms (1-5MW) particularly for industrial customers. HgCapital provides working capital to the company and holds majority ownership of the wind assets. Coordinates 52.415065°, -1.777849° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":52.415065,"lon":-1.777849,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

102

Applying micro scales of horizontal axis wind turbines for operation in low wind speed regions  

Science Journals Connector (OSTI)

Abstract Utilizing the micro scales of wind turbines could noticeably supply the demand for the electricity in low wind speed regions. Aerodynamic design and optimization of the blade, as a main part of a wind turbine, were addressed in the study. Three micro scales of horizontal axis wind turbines with output power of 0.5, 0.75 and 1 kW were considered and the geometric optimization of the blades in terms of the two involved parameters, chord and twist, was undertaken. In order to improve the performance of the turbines at low wind speeds, starting time was included in an objective function in addition to the output power – the main and desirable goal of the wind turbine blade design. A purpose-built genetic algorithm was employed to maximize both the output power and the starting performance which were calculated by the blade-element momentum theory. The results emphasize that the larger values of the chord and twist at the root part of the blades are indispensable for the better performance when the wind speed is low. However, the noticeable value of the generator resistive torque could largely delay the starting of the micro-turbines especially for the considered smaller size, 0.5 kW, where the starting aerodynamic torque could not overcome the generator resistive torque. For that size, an increase in the number of blades improved both the starting performance and also output power.

Abolfazl Pourrajabian; Reza Ebrahimi; Masoud Mirzaei

2014-01-01T23:59:59.000Z

103

Simultaneous Retreival of Surface Wind Speed and Rain Rate using Radar and Radiometer Measurements  

E-Print Network [OSTI]

to simultaneously retrieve the vertical profile of precipitation and the near-surface wind speed. ResultsSimultaneous Retreival of Surface Wind Speed and Rain Rate using Radar and Radiometer Measurements simultaneously estimates the over ocean near-surface wind speed and rain rate profile using data from a 10.7 GHz

Ruf, Christopher

104

A Robust STATCOM Control to Augment LVRT capability of Fixed Speed Wind Turbines  

E-Print Network [OSTI]

A Robust STATCOM Control to Augment LVRT capability of Fixed Speed Wind Turbines M. J. Hossain, H Compensator (STATCOM) to enhance the Low-Voltage Ride- Through (LVRT) capability of fixed-speed wind turbines cost and maintenance due to rugged brushless construction. Constant speed wind turbines equipped

Pota, Himanshu Roy

105

Wind speed influence on phytoplankton bloom dynamics in the Southern Ocean Marginal Ice Zone  

E-Print Network [OSTI]

Niebauer, H. J. (1982), Wind and melt driven circulation inJ. K. Moore (2007), Wind speed influence on phytoplanktonby the NASA Ocean Vector Winds Science Team. Data are

Fitch, Dillon T; Moore, J. Keith

2007-01-01T23:59:59.000Z

106

Observed and CAM3 GCM Sea Surface Wind Speed Distributions: Characterization, Comparison, and Bias Reduction  

E-Print Network [OSTI]

data, all from 2000 to 2005. Wind speed mean, 90th percentile, standard deviation, and Weibull shape and energy fluxes depend nonlinearly on wind speed magnitude, are sensitive to the tails of the wind statistics, particularly in the Southern Hemisphere storm track, consistent with the hypothesis. These wind

Zender, Charles

107

Solar wind suprathermal electron Stahl widths across high-speed stream structures  

SciTech Connect (OSTI)

Suprathermal electrons (100-1500 eV) observed in the solar wind typically show a strahl distribution, that is, a beam directed away from the Sun along the magnetic field direction. The strahl width observed at 1 AU is highly variable, ranging from 10-70 degrees. The obsenred finite width of the strahl results from the competition between beam focusing as the interplanetary magnetic field strength drops with distance from the Sun, and pitch-angle scattering as the beam interacts with the solar wind plasma in transit from the sun. Here we examine strahl width, observed with ACE SWEPAM across high-speed stream structures to investigate variations in electron scattering as a function of local plasma characteristics. We find that narrow strahls (less than 20 degrees wide), indicating reduced scattering, are observed within high-speed streams. Narrow strahls are also observed in both very low temperature solar wind, in association with ICMEs. Case studies of high-speed streams typically show the strahl narrowing at the leading edge of the stream. In some cases, the strahl narrows at the reverse shock or pressure wave, in other cases at the stream interface. The narrowing can either occur discontinuously or gradually over a period of hours. Within the high-speed wind, the strahl remains narrow for a period of hours to days, and then gradually broadens. The strahl width is roughly constant at all energies across these structures. For some fraction of high-speed streams, counterstreaming is associated with passage of the corotating interaction region. In these cases, we find the widths of the two counterstreaming beams frequently differ by more than 40 degrees. This dramatic difference in strahl width contrasts with observations in the solar wind as a whole, in which counterstreaming strahls typically differ in width by less than 20 degrees.

Skoug, Ruth M [Los Alamos National Laboratory; Steinberg, John T [Los Alamos National Laboratory; Goodrich, Katherine A [Los Alamos National Laboratory; Anderson, Brett R [DARTMUTH UNIV.

2011-01-03T23:59:59.000Z

108

Long-distance seed dispersal by wind: disentangling the effects of species traits, vegetation types, vertical turbulence and wind speed  

Science Journals Connector (OSTI)

Long-distance dispersal (LDD) of plant seeds by wind is affected by functional traits of the ... , as well as by the meteorological parameters wind speed and vertical turbulence. The relative importance of ... fo...

Felix Heydel; Sarah Cunze; Markus Bernhardt-Römermann…

2014-07-01T23:59:59.000Z

109

MASON LAB B-7 WIND TUNNEL OPERATING INSTRUCTIONS Our wind tunnel is a low speed tunnel with a test section 15"x24" It has a digital controller  

E-Print Network [OSTI]

MASON LAB B-7 WIND TUNNEL OPERATING INSTRUCTIONS Our wind tunnel is a low speed tunnel with a test approximate wind tunnel speed in m/s (meters/second) and tunnel speed will go to that set point speed measure lift (~25 N) and drag (~8 N) PRECAUTIONS: ALL OBJECTS MUST BE SECURED BEFORE STARTING WIND TUNNEL

Haller, Gary L.

110

Correlation analysis for wind speed and failure rate of wind turbines using time series approach  

Science Journals Connector (OSTI)

The correlation between wind speed and failure rate (FR) of wind turbines is analyzed with time series approach. The time series of power index (PI) and FR of wind turbines are established based on historical data which are pretreated by singularity processing stationarity processing and wavelet de-noising. The trend variations of the time series are analyzed from both time domain and frequency domain by extracting the indicator functions including auto-correlation function cross-correlation function and spectral density function. A case study is given out to verify the validity of the model and the method which is based on the wind speed and failure data from January 1995 to December of 2002 in Nordjylland Denmark. Auto-correlation function and spectral density function show that time series of PI and FR have strong seasonal characteristics and quite similar periodicity while the cross-correlation function shows they keep high consistency and strong correlation. The results indicate that by calculating and monitoring PI the failure rule of wind turbines can be forecast which provides theoretical basis for preventive maintenance of wind turbines.

Chun Su; Quan Jin; Yequn Fu

2012-01-01T23:59:59.000Z

111

Pitch-Controlled Variable-Speed Wind Turbine Generation  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Pitch-Controlled Variable-Speed Pitch-Controlled Variable-Speed Wind Turbine Generation February 2000 * NREL/CP-500-27143 E. Muljadi and C.P. Butterfield Presented at the 1999 IEEE Industry Applications Society Annual Meeting Phoenix, Arizona October 3-7, 1999 National Renewable Energy Laboratory 1617 Cole Boulevard Golden, Colorado 80401-3393 NREL is a U.S. Department of Energy Laboratory Operated by Midwest Research Institute * * * * Battelle * * * * Bechtel Contract No. DE-AC36-99-GO10337 NOTICE The submitted manuscript has been offered by an employee of the Midwest Research Institute (MRI), a contractor of the US Government under Contract No. DE-AC36-99GO10337. Accordingly, the US Government and MRI retain a nonexclusive royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for US Government purposes.

112

Tracking an Aerodynamic Model in a Wind Tunnel with a Stereo High-speed Imaging System  

E-Print Network [OSTI]

Tracking an Aerodynamic Model in a Wind Tunnel with a Stereo High-speed Imaging System Lichuan Gui in wind tunnel tests with a stereo high-speed imaging system. The imaging system includes two high angle, pitch angle and yaw angle of the aerodynamic model in the wind tunnel. Tests and simulations were

Gui, Lichuan

113

Sliding Mode Power Control of Variable Speed Wind Energy Conversion Systems  

E-Print Network [OSTI]

Sliding Mode Power Control of Variable Speed Wind Energy Conversion Systems B. Beltran, T. Ahmed power generation in variable speed wind energy conversion systems (VS-WECS). These systems have two variations. Index Terms--Wind energy conversion system, power generation control, sliding mode control

Boyer, Edmond

114

Letters: Neural network based hybrid computing model for wind speed prediction  

Science Journals Connector (OSTI)

This paper proposes a Neural Network based hybrid computing model for wind speed prediction in renewable energy systems. Wind energy is one of the renewable energy sources which lower the cost of electricity production. Due to the fluctuation and nonlinearity ... Keywords: Hybrid Model, Multilayer Perceptron, Neural Networks, Self Organizing Maps, Wind Speed Prediction

K. Gnana Sheela; S. N. Deepa

2013-12-01T23:59:59.000Z

115

Wind: wind speed and wind power density GIS data at 50m above ground and  

Open Energy Info (EERE)

Kenya from RisoeDTU Kenya from RisoeDTU Dataset Summary Description (Abstract): These data are results from the KAMM/WASP studies for Kenya. The KAMM/WAsP methodology uses a set of wind classes to represent wind conditions for the mapped region. A mesoscale simulation for each wind class, using KAMM (Karlsruhe Mesoscale Model), is performed and statistics performed on the model output. The results are a summary of the simulated wind climate, and ii. a wind atlas, a summary of the wind climate standardized to flat, uniform roughness terrain. (Purpose): The product is intended to be used to estimate the wind resource potential in the country including the the spatial variability. This map covers regions where long term measurements are not available. In a sense this is the point of the

116

Wind: wind speed and wind power density GIS data at 50m above ground and  

Open Energy Info (EERE)

Bangladesh from RisoeDTU Bangladesh from RisoeDTU Dataset Summary Description (Abstract): These data are results from the KAMM/WASP studies for Bangladesh. Version 2 is an updated version of the earlier release and includes an adjustment to Weibull A and k to bring the Atlas values into better agreement with observations. See supplemental information.The KAMM/WAsP methodology uses a set of wind classes to represent wind conditions for the mapped region. A mesoscale simulation for each wind class, using KAMM (Karlsruhe Mesoscale Model), is performed and statistics performed on the model output. The result is i. a wind resource map, a summary of the simulated wind climate, and ii. a wind atlas, a summary of the wind climate standardized to flat, uniform roughness terrain. (Purpose): The product is intended to be used to

117

Variable speed wind turbine generator with zero-sequence filter  

DOE Patents [OSTI]

A variable speed wind turbine generator system to convert mechanical power into electrical power or energy and to recover the electrical power or energy in the form of three phase alternating current and return the power or energy to a utility or other load with single phase sinusoidal waveform at sixty (60) hertz and unity power factor includes an excitation controller for generating three phase commanded current, a generator, and a zero sequence filter. Each commanded current signal includes two components: a positive sequence variable frequency current signal to provide the balanced three phase excitation currents required in the stator windings of the generator to generate the rotating magnetic field needed to recover an optimum level of real power from the generator; and a zero frequency sixty (60) hertz current signal to allow the real power generated by the generator to be supplied to the utility. The positive sequence current signals are balanced three phase signals and are prevented from entering the utility by the zero sequence filter. The zero sequence current signals have zero phase displacement from each other and are prevented from entering the generator by the star connected stator windings. The zero sequence filter allows the zero sequence current signals to pass through to deliver power to the utility. 14 figs.

Muljadi, E.

1998-08-25T23:59:59.000Z

118

Variable Speed Wind Turbine Generator with Zero-sequence Filter  

DOE Patents [OSTI]

A variable speed wind turbine generator system to convert mechanical power into electrical power or energy and to recover the electrical power or energy in the form of three phase alternating current and return the power or energy to a utility or other load with single phase sinusoidal waveform at sixty (60) hertz and unity power factor includes an excitation controller for generating three phase commanded current, a generator, and a zero sequence filter. Each commanded current signal includes two components: a positive sequence variable frequency current signal to provide the balanced three phase excitation currents required in the stator windings of the generator to generate the rotating magnetic field needed to recover an optimum level of real power from the generator; and a zero frequency sixty (60) hertz current signal to allow the real power generated by the generator to be supplied to the utility. The positive sequence current signals are balanced three phase signals and are prevented from entering the utility by the zero sequence filter. The zero sequence current signals have zero phase displacement from each other and are prevented from entering the generator by the star connected stator windings. The zero sequence filter allows the zero sequence current signals to pass through to deliver power to the utility.

Muljadi, Eduard (Golden, CO)

1998-08-25T23:59:59.000Z

119

Variable speed wind turbine generator with zero-sequence filter  

DOE Patents [OSTI]

A variable speed wind turbine generator system to convert mechanical power into electrical power or energy and to recover the electrical power or energy in the form of three phase alternating current and return the power or energy to a utility or other load with single phase sinusoidal waveform at sixty (60) hertz and unity power factor includes an excitation controller for generating three phase commanded current, a generator, and a zero sequence filter. Each commanded current signal includes two components: a positive sequence variable frequency current signal to provide the balanced three phase excitation currents required in the stator windings of the generator to generate the rotating magnetic field needed to recover an optimum level of real power from the generator; and a zero frequency sixty (60) hertz current signal to allow the real power generated by the generator to be supplied to the utility. The positive sequence current signals are balanced three phase signals and are prevented from entering the utility by the zero sequence filter. The zero sequence current signals have zero phase displacement from each other and are prevented from entering the generator by the star connected stator windings. The zero sequence filter allows the zero sequence current signals to pass through to deliver power to the utility.

Muljadi, Eduard (Golden, CO)

1998-01-01T23:59:59.000Z

120

File:QuikSCAT - Annual Wind Speed at 10 m.pdf | Open Energy Information  

Open Energy Info (EERE)

QuikSCAT - Annual Wind Speed at 10 m.pdf QuikSCAT - Annual Wind Speed at 10 m.pdf Jump to: navigation, search File File history File usage QuikSCAT - Annual Wind Speed at 10 m Size of this preview: 463 × 599 pixels. Other resolution: 464 × 600 pixels. Full resolution ‎(1,275 × 1,650 pixels, file size: 1.19 MB, MIME type: application/pdf) Title Annual Wind Speed at 10 m Description QuikSCAT - Annual Wind Speed at 10 m Sources NREL, National Aeronautics and Space Administration Extent International Coordinates 0°, 0° Scatterometer measurements of the state of the ocean surface are used to estimate 10-m ocean winds in the QuikSCAT satellite data set. The QuikSCAT data are produced by Remote Sensing Systems and sponsored by the U.S. National Aeronautics and Space Administration Ocean Vector Winds Science

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

WIND/RAIN BACKSCATTER MODELING AND WIND/RAIN RETRIEVAL FOR SCATTEROMETER AND  

E-Print Network [OSTI]

/rain backscatter model is developed that has inputs of surface rain rate, incidence angle, wind speed, wind from rain causes estimated wind speeds to be biased high and estimated wind directions to be biased directions are used as the wind direction estimate and the wind speed is derived from SAR by inversion

Long, David G.

122

Low Wind Speed Turbine Development Project Report: November 4, 2002 - December 31, 2006  

SciTech Connect (OSTI)

This report summarizes work conducted by Clipper Windpower under the DOE Low Wind Speed Turbine project. The objective of this project was to produce a wind turbine that can lower the cost of energy.

Mikhail, A.

2009-01-01T23:59:59.000Z

123

An improved wind speed algorithm for “Jason-1” altimeter under tropical cyclone conditions  

Science Journals Connector (OSTI)

Rain effect and lack of in situ validation data are two main causes of tropical cyclone wind retrieval errors. The National Oceanic and Atmospheric ... (NRCS); Hurricane Research Division (HRD) wind speed, which ...

Bangyong Qin; Xuan Zhou; Honglei Zhang; Xiaofeng Yang; Rong Lu…

2014-07-01T23:59:59.000Z

124

A WRF Ensemble for Improved Wind Speed Forecasts at Turbine Height  

Science Journals Connector (OSTI)

The Weather Research and Forecasting Model (WRF) with 10-km horizontal grid spacing was used to explore improvements in wind speed forecasts at a typical wind turbine hub height (80 m). An ensemble consisting of WRF model simulations with ...

Adam J. Deppe; William A. Gallus Jr.; Eugene S. Takle

2013-02-01T23:59:59.000Z

125

An Isofactorial Change-of-Scale Model for the Wind Speed Probability Density Function  

Science Journals Connector (OSTI)

The wind speed probability density function (PDF) is used in a variety of applications in meteorology, oceanography, and climatology usually as a dataset comparison tool of a function of a quantity such as momentum flux or wind power density. The ...

Mark L. Morrissey; Angie Albers; J. Scott Greene; Susan Postawko

2010-02-01T23:59:59.000Z

126

The effect of wind speed fluctuations on the performance of a wind-powered membrane system for brackish water desalination   

E-Print Network [OSTI]

A wind-powered reverse osmosis membrane (wind-membrane) system without energy storage was tested using synthetic brackish water (2750 and 5500 mg/L NaCl) over a range of simulated wind speeds under both steady-state and ...

Park, Gavin L.; Schäfer, Andrea; Richards, Bryce S.

2011-01-01T23:59:59.000Z

127

A first order geometric auto regressive process for boundary layer wind speed simulation  

Science Journals Connector (OSTI)

Under certain conditions the first order geometric auto regressive (AR) process has statistical properties similar to atmospheric boundary layer wind speed. In this contribution, we investigate ... this stochas...

T. Laubrich; H. Kantz

2009-08-01T23:59:59.000Z

128

About First Order Geometric Auto Regressive Processes for Boundary Layer Wind Speed Simulation  

Science Journals Connector (OSTI)

Under certain conditions the first order geometric auto regressive process has statistical properties similar to atmospheric boundary layer wind speed. In this contribution, we investigate ... this stochastic pro...

Thomas Laubrich; Holger Kantz

2010-01-01T23:59:59.000Z

129

E-Print Network 3.0 - accurate wind speed Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Summary: anywhere in the world. As the annual mean wind speed goes up, the cost per energy unit decreases, hence... measurements are obtained at one point. Satellite derived...

130

Master's thesis: "Wind speed measurements in an offshore wind farm by remote sensing: Comparison of radar satellite TerraSAR-X and ground-based  

E-Print Network [OSTI]

Master's thesis: "Wind speed measurements in an offshore wind farm by remote sensing: Comparison of the Offshore wind farm alpha ventus with 12 wind turbines, substation and met mast Fino1. Southerly winds cause (wake) caused by wind farms and especially for the interaction of large offshore wind farms, which can

Peinke, Joachim

131

Wind Speed Estimation and Parametrization of Wake Models for Downregulated Offshore Wind Farms within the scope of PossPOW Project  

Science Journals Connector (OSTI)

With increasing installed capacity, wind farms are requested to downregulate more frequently, especially in the offshore environment. Determination and verification of possible (or available) power of downregulated offshore wind farms are the aims of the PossPOW project (see PossPOW.dtu.dk). Two main challenges encountered in the project so far are the estimation of wind speed and the recreation of the flow inside the downregulated wind farm as if it is operating ideally. The rotor effective wind speed was estimated using power, pitch angle and rotational speed as inputs combined with a generic Cp model. The results have been compared with Horns Rev-I dataset and NREL 5MW simulations under both downregulation and normal operation states. For the real-time flow recreation, the GCLarsen single wake model was re-calibrated using a 1-s dataset from Horns Rev and tested for the downregulated period. The re-calibrated model has to be further parametrized to include dynamic effects such as wind direction variability and meandering also considering different averaging time scales before implemented in full scale wind farms.

Tuhfe Göçmen Bozkurt; Gregor Giebel; Niels Kjřlstad Poulsen; Mahmood Mirzaei

2014-01-01T23:59:59.000Z

132

Wind: wind speed and wind power density GIS data at 50m above ground and  

Open Energy Info (EERE)

Ethiopia from RisoeDTU Ethiopia from RisoeDTU Dataset Summary Description (Abstract): These data are results from the KAMM/WASP studies for Ethiopia. The KAMM/WAsP methodology uses a set of wind classes to represent wind conditions for the mapped region. A mesoscale simulation for each wind class, using KAMM (Karlsruhe Mesoscale Model), is performed and statistics performed on the model output. The results are a summary of the simulated wind climate, and ii.a wind atlas, a summary of the wind climate standardized to flat, uniform roughness terrain. (Purpose): The product is intended to be used to estimate the wind resource potential in the country including the spatial variability. This map covers regions where long term measurements are not available. In a sense this is the point of the mapping exercise, but it also means that verification of results has not been as complete would be ideal. There is some concern that the results may underestimate the resource. However, new measurement data is coming and revisions to the map may be made if necessary as verification is carried out.

133

Can Satellite Sampling of Offshore Wind Speeds Realistically Represent Wind Speed Distributions? Part II: Quantifying Uncertainties Associated with Distribution Fitting Methods  

Science Journals Connector (OSTI)

Remote sensing tools represent an attractive proposition for measuring wind speeds over the oceans because, in principle, they also offer a mechanism for determining the spatial variability of flow. Presented here is the continuation of research ...

S. C. Pryor; M. Nielsen; R. J. Barthelmie; J. Mann

2004-05-01T23:59:59.000Z

134

A WRF Ensemble for Improved Wind Speed Forecasts at Turbine Height ADAM J. DEPPE AND WILLIAM A. GALLUS JR.  

E-Print Network [OSTI]

A WRF Ensemble for Improved Wind Speed Forecasts at Turbine Height ADAM J. DEPPE AND WILLIAM A in wind speed forecasts at a typical wind turbine hub height (80 m). An ensemble consisting of WRF model ensemble members for forecasting wind speed. A second configuration using three random perturbations

McCalley, James D.

135

Effects of Rain Rate and Wind Magnitude on SeaWinds Scatterometer Wind Speed Errors  

Science Journals Connector (OSTI)

Rain within the footprint of the SeaWinds scatterometer on the QuikSCAT satellite causes more significant errors than existed with its predecessor, the NASA scatterometer (NSCAT) on Advanced Earth Observing Satellite-I (ADEOS-I). Empirical ...

David E. Weissman; Mark A. Bourassa; Jeffrey Tongue

2002-05-01T23:59:59.000Z

136

Wind: wind speed and wind power density GIS data at 50m above ground and  

Open Energy Info (EERE)

Nepal from RisoeDTU Nepal from RisoeDTU Dataset Summary Description (Abstract): These data are results from the KAMM/WASP studies for Nepal. The KAMM/WAsP methodology uses a set of windclasses to represent wind conditions for the mapped region. A mesoscale simulation for each wind class, using KAMM (Karlsruhe Mesoscale Model), is performed and statistics performed on the model output. The results are a summary of the simulated wind climate, and a wind atlas, a summary of the wind climate standardized to flat, uniform roughness terrain. (Purpose): The product is intended to be used to estimate the wind resource potential in the country including the the spatial variability. This map covers regions where long term measurements are not available. In a sense this is the point of the mapping exercise, but it also means that verification of results has not been as complete would be ideal. There is some concern that the results may underestimate the resource. However, new measurement data is coming and revisions to the map may be made if necessary as verification is carried out.

137

Numerical simulation of aerodynamic derivatives and critical wind speed for long-span bridges based on simplified steady wind field  

Science Journals Connector (OSTI)

Combining the computational fluid dynamics-based numerical simulation with the forced vibration technique for extraction ... calculating the aerodynamic derivatives and the critical flutter wind speed for long-sp...

Dabo Xin Ph.D. Student ???; Jinping Ou ???

2007-06-01T23:59:59.000Z

138

Wind Conditions in a Fjordlike Bay and Predictions of Wind Speed Using Neighboring Stations Employing Neural Network Models  

Science Journals Connector (OSTI)

This paper evaluates the applicability of neural networks for estimating wind speeds at various target locations using neighboring reference locations along the south coast of Newfoundland, Canada. The stations were chosen to cover a variety of ...

Jens J. Currie; Pierre J. Goulet; Andry W. Ratsimandresy

2014-06-01T23:59:59.000Z

139

Ris0-M-2829 2 Extreme Values ofWind Speeds  

E-Print Network [OSTI]

Ris0-M-2829 2 Extreme Values ofWind Speeds overthe Great Belt Region N.O. Jensen and B. Nielsen Ris events 9 4 Extrapolation to the 50-year storm 11 5 Discussion of the 50-year wind 15 6 Crosswind extremes for extreme values of wind speeds. The data material was obtained from a 70-m mast on a small island, Sprog0

140

Instrument Design Simulations for Synthetic Aperture Microwave Radiometric Imaging of Wind Speed and  

E-Print Network [OSTI]

Instrument Design Simulations for Synthetic Aperture Microwave Radiometric Imaging of Wind Speed, US Abstract -- The measurement of peak winds in hurricanes is critical to forecasting intensity in radiative transfer modeling for hurricane force winds and large incidence angles are required for HIRad

Ruf, Christopher

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Modelling and Analysis of Variable Speed Wind Turbines with Induction Generator during Grid  

E-Print Network [OSTI]

Modelling and Analysis of Variable Speed Wind Turbines with Induction Generator during Grid Fault Wind Turbines with Induction Generator during Grid Fault by Sigrid M. Bolik Institute of Energy turbine technology has undergone rapid developments. Growth in size and the optimization of wind turbines

Hansen, René Rydhof

142

Individual Pitch Control for Mitigation of Power Fluctuation of Variable Speed Wind Turbines  

E-Print Network [OSTI]

Individual Pitch Control for Mitigation of Power Fluctuation of Variable Speed Wind Turbines, China mcheng@seu.edu.cn Abstract-- Grid connected wind turbines are the sources of power fluctuations presents an individual pitch control (IPC) strategy to mitigate the wind turbine power fluctuation at both

Hu, Weihao

143

EVALUATION OF MODELS FOR THE VERTICAL EXTRAPOLATION OF WIND SPEED MEASUREMENTS AT OFFSHORE SITES  

E-Print Network [OSTI]

EVALUATION OF MODELS FOR THE VERTICAL EXTRAPOLATION OF WIND SPEED MEASUREMENTS AT OFFSHORE SITES important for offshore wind energy utilisation are discussed and tested: Four models for the surface tested with data from the offshore field measurement Rødsand by extrapolating the measured 10 m wind

Heinemann, Detlev

144

The Impacts of Wind Speed Trends and Long-term Variability in Relation to Hydroelectric  

E-Print Network [OSTI]

The Impacts of Wind Speed Trends and Long- term Variability in Relation to Hydroelectric Reservoir and Long-term Variability in Relation to Hydroelectric Reservoir Inflows on Wind Power in the Pacific through diversification. In hydroelectric dominated systems, like the PNW, the benefits of wind power can

Kohfeld, Karen

145

An aero-elastic flutter based electromagnetic energy harvester with wind speed augmenting funnel  

E-Print Network [OSTI]

An aero-elastic flutter based electromagnetic energy harvester with wind speed augmenting funnel been used to convert wind flow energy into mechanical vibration, which is then transformed-scale renewable energy generating systems such as wind turbines, thermal generators, and solar panels, energy

Stanford University

146

An Examination of Tropical and Extratropical Gust Factors and the Associated Wind Speed Histograms  

Science Journals Connector (OSTI)

A gust factor, defined as the ratio between a peak wind gust and mean wind speed over a period of time, can be used along with other statistics to examine the structure of the wind. Gust factors are heavily dependent on upstream terrain ...

B. M. Paulsen; J. L. Schroeder

2005-02-01T23:59:59.000Z

147

Soft computing based optimum parameter design of PID controller in rotor speed control of wind turbines  

Science Journals Connector (OSTI)

Sensitivity and robustness is the primary issue while designing the controller for large non-linear systems such as offshore wind turbines. The main goal of this study is a novel soft computing based approach in controlling the rotor speed of wind turbine. ... Keywords: bacteria foraging optimization algorithm, optimization, particle swarm optimization, proportional-integral-derivative controller, wind turbines

R. Manikandan; Nilanjan Saha

2011-12-01T23:59:59.000Z

148

Magnetic-Driven Winds from Post-AGB Stars: Solutions for High Speed Winds and Extreme Collimation  

E-Print Network [OSTI]

This paper explores the effects of post-AGB winds driven solely by magnetic pressure from the stellar surface. It is found that winds can reach high speeds under this assumption, and lead to the formation of highly collimated proto-planetary nebulae. Bipolar knotty jets with periodic features and constant velocity are well reproduced by the models. Several wind models with terminal velocities from a few tens of $\\kms$ up to $10^3$ $\\kms$ are calculated, yielding outflows with linear momenta in the range $10^{36}-10^{40} \\gcms$, and kinetic energies in the range $10^{42}-10^{47} $ erg. These results are in accord with recent observations of proto-planetary nebulae that have pointed out serious energy and momentum deficits if radiation pressure is considered as the only driver for these outflows. Our models strengthen the notion that the large mass-loss rates of post-AGB stars, together with the short transition times from the late AGB to the planetary nebula stage, could be directly linked with the generation of strong magnetic fields during this transition stage.

Guillermo Garcia-Segura; Jose Alberto Lopez; Jose Franco

2004-09-24T23:59:59.000Z

149

Classification of Vertical Wind Speed Profiles Observed Above a Sloping Forest at Nighttime Using the Bulk Richardson Number  

Science Journals Connector (OSTI)

Wind speed profiles above a forest canopy relate to ... atmosphere. Many studies have reported that vertical wind speed profiles above a relatively flat forest can ... be classified by a stability index developed...

Hikaru Komatsu; Norifumi Hotta; Koichiro Kuraji…

2005-05-01T23:59:59.000Z

150

First and second order semi-Markov chains for wind speed modeling  

E-Print Network [OSTI]

The increasing interest in renewable energy, particularly in wind, has given rise to the necessity of accurate models for the generation of good synthetic wind speed data. Markov chains are often used with this purpose but better models are needed to reproduce the statistical properties of wind speed data. We downloaded a database, freely available from the web, in which are included wind speed data taken from L.S.I. -Lastem station (Italy) and sampled every 10 minutes. With the aim of reproducing the statistical properties of this data we propose the use of three semi-Markov models. We generate synthetic time series for wind speed by means of Monte Carlo simulations. The time lagged autocorrelation is then used to compare statistical properties of the proposed models with those of real data and also with a synthetic time series generated though a simple Markov chain.

D'Amico, Guglielmo; Prattico, Flavio

2012-01-01T23:59:59.000Z

151

Integral variable structure current control of DFIG-based wind turbines near cut-in speed  

Science Journals Connector (OSTI)

Based on the grid voltage orientated vector control technique, a novel integral variable structure controller for current control of variable speed doubly fed induction generator (DFIG) wind turbines near cut-in wind speed is proposed. The proposed current controller can not only ensure generators' safe cut-in switches to the grid, but also maximum energy capture after switch motion without any regulations. By these, simulations of a 1.5 MW DFIG-based wind turbine near cut-in wind speed are separately conducted under integral variable structure control (IVSC) and PI control. The results show that IVSC strategy, which gives better dynamic response, less static error, smaller controller output dithering, stronger global robustness against generator parameters uncertainty and the grid voltage fluctuation, as well as needless controller regulation after cutting-in the grid, obviously preponderates over traditional PI control for DFIG-based wind turbines near cut-in speed.

Changliang Xia; Huimin Wang; Zhanfeng Song

2009-01-01T23:59:59.000Z

152

Dependency of U.S. Hurricane Economic Loss on Maximum Wind Speed and Storm Size  

E-Print Network [OSTI]

Many empirical hurricane economic loss models consider only wind speed and neglect storm size. These models may be inadequate in accurately predicting the losses of super-sized storms, such as Hurricane Sandy in 2012. In this study, we examined the dependencies of normalized U.S. hurricane loss on both wind speed and storm size for 73 tropical cyclones that made landfall in the U.S. from 1988 to 2012. A multi-variate least squares regression is used to construct a hurricane loss model using both wind speed and size as predictors. Using maximum wind speed and size together captures more variance of losses than using wind speed or size alone. It is found that normalized hurricane loss (L) approximately follows a power law relation with maximum wind speed (Vmax) and size (R). Assuming L=10^c Vmax^a R^b, c being a scaling factor, the coefficients, a and b, generally range between 4-12 and 2-4, respectively. Both a and b tend to increase with stronger wind speed. For large losses, a weighted regression model, with...

Zhai, Alice R

2014-01-01T23:59:59.000Z

153

A new hybrid model optimized by an intelligent optimization algorithm for wind speed forecasting  

Science Journals Connector (OSTI)

Abstract Forecasting the wind speed is indispensable in wind-related engineering studies and is important in the management of wind farms. As a technique essential for the future of clean energy systems, reducing the forecasting errors related to wind speed has always been an important research subject. In this paper, an optimized hybrid method based on the Autoregressive Integrated Moving Average (ARIMA) and Kalman filter is proposed to forecast the daily mean wind speed in western China. This approach employs Particle Swarm Optimization (PSO) as an intelligent optimization algorithm to optimize the parameters of the ARIMA model, which develops a hybrid model that is best adapted to the data set, increasing the fitting accuracy and avoiding over-fitting. The proposed method is subsequently examined on the wind farms of western China, where the proposed hybrid model is shown to perform effectively and steadily.

Zhongyue Su; Jianzhou Wang; Haiyan Lu; Ge Zhao

2014-01-01T23:59:59.000Z

154

Luminescence intensity in coral skeletons from Mona Island in the Caribbean Sea and its link to precipitation and wind speed  

Science Journals Connector (OSTI)

...and its link to precipitation and wind speed Johan Nyberg 1 Present address...proxy of precipitation and (trade) wind speed. In order to find wavelength pairs...records of regional precipitation and wind speed. In the coral skeleton as well...

2002-01-01T23:59:59.000Z

155

Long-term-average, solar cycle, and seasonal response of magnetospheric energetic electrons to the solar wind speed  

E-Print Network [OSTI]

to the solar wind speed D. Vassiliadis,1 A. J. Klimas,2 S. G. Kanekal,3 D. N. Baker,3 and R. S. Weigel4. [1] Among the interplanetary activity parameters the solar wind speed is the one best correlated, and seasonal response of magnetospheric energetic electrons to the solar wind speed, J. Geophys. Res., 107(A11

Vassiliadis, Dimitrios

156

Evidence of a Threshold Wind Speed in Tower-mounted Scatterometer Data David W. Draper and David G. Long  

E-Print Network [OSTI]

Evidence of a Threshold Wind Speed in Tower-mounted Scatterometer Data David W. Draper and David G ) in scatterom- eter measurements over water is theorized to go to zero below a threshold wind speed due. Evidence of the threshold wind speed and a hysteresis effect have been observed in airship and wave tank

Long, David G.

157

Evidence of trends in near-surface wind speeds over the Baltic S.C. Pryor1,2  

E-Print Network [OSTI]

1 Evidence of trends in near-surface wind speeds over the Baltic S.C. Pryor1,2 , R.J. Barthelmie2 and Atmospheric Physics, Risoe National Laboratory, DK4000 Roskilde, Denmark ABSTRACT Annual mean wind speeds over associated with increases in the upper quartile of the wind speed distribution and the winter season. Trends

158

Luminescence intensity in coral skeletons from Mona Island in the Caribbean Sea and its link to precipitation and wind speed  

Science Journals Connector (OSTI)

...Precipitation and wind speed in combination may thus...well as turbidity and light availability. The negative...con- trolled by wind speed, precipitation and run-off...precipitation and wind speed may control some environmental...as freshwater supply, light availability and/or...

2002-01-01T23:59:59.000Z

159

Diabatic wind speed profiles in coastal regions: Comparison of an internal boundary layer (IBL) model with observations  

Science Journals Connector (OSTI)

A model is presented to transform wind speed observations at a single height over sea ... of 100 m). Only moderate and strong winds from the sea are considered, which are particularly important for wind energy ap...

A. C. M. Beljaars; A. A. M. Holtslag; W. C. Turkenburg

1990-04-01T23:59:59.000Z

160

Application of an Improved SVM Algorithm for Wind Speed Forecasting  

Science Journals Connector (OSTI)

An improved Support Vector Machine (SVM) algorithm is used to forecast wind in Doubly Fed Induction Generator (DFIG) wind power system without aerodromometer. The ... Validation (CV) method. Finally, 3.6MW DFIG w...

Huaqiang Zhang; Xinsheng Wang; Yinxiao Wu

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

LIDAR Wind Speed Measurement Analysis and Feed-Forward Blade Pitch Control for Load Mitigation in Wind Turbines: January 2010--January 2011  

SciTech Connect (OSTI)

This report examines the accuracy of measurements that rely on Doppler LIDAR systems to determine their applicability to wind turbine feed-forward control systems and discusses feed-forward control system designs that use preview wind measurements. Light Detection and Ranging (LIDAR) systems are able to measure the speed of incoming wind before it interacts with a wind turbine rotor. These preview wind measurements can be used in feed-forward control systems designed to reduce turbine loads. However, the degree to which such preview-based control techniques can reduce loads by reacting to turbulence depends on how accurately the incoming wind field can be measured. The first half of this report examines the accuracy of different measurement scenarios that rely on coherent continuous-wave or pulsed Doppler LIDAR systems to determine their applicability to feed-forward control. In particular, the impacts of measurement range and angular offset from the wind direction are studied for various wind conditions. A realistic case involving a scanning LIDAR unit mounted in the spinner of a wind turbine is studied in depth with emphasis on choices for scan radius and preview distance. The effects of turbulence parameters on measurement accuracy are studied as well. Continuous-wave and pulsed LIDAR models based on typical commercially available units were used in the studies present in this report. The second half of this report discusses feed-forward control system designs that use preview wind measurements. Combined feedback/feed-forward blade pitch control is compared to industry standard feedback control when simulated in realistic turbulent above-rated winds. The feed-forward controllers are designed to reduce fatigue loads, increasing turbine lifetime and therefore reducing the cost of energy. Three feed-forward designs are studied: non-causal series expansion, Preview Control, and optimized FIR filter. The input to the feed-forward controller is a measurement of incoming wind speeds that could be provided by LIDAR. Non-causal series expansion and Preview Control methods reduce blade root loads but increase tower bending in simulation results. The optimized FIR filter reduces loads overall, keeps pitch rates low, and maintains rotor speed regulation and power capture, while using imperfect wind measurements provided by the spinning continuous-wave LIDAR model.

Dunne, F.; Simley, E.; Pao, L.Y.

2011-10-01T23:59:59.000Z

162

ARM - Evaluation Product - Derived Wind Profiles from Doppler...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

the radial velocity data; the amplitude, phase and offset of the sinusoid determine the wind speed, wind direction and vertical velocity, respectively. The derived winds are...

163

Wind speed forecasting at different time scales: a non parametric approach  

E-Print Network [OSTI]

The prediction of wind speed is one of the most important aspects when dealing with renewable energy. In this paper we show a new nonparametric model, based on semi-Markov chains, to predict wind speed. Particularly we use an indexed semi-Markov model, that reproduces accurately the statistical behavior of wind speed, to forecast wind speed one step ahead for different time scales and for very long time horizon maintaining the goodness of prediction. In order to check the main features of the model we show, as indicator of goodness, the root mean square error between real data and predicted ones and we compare our forecasting results with those of a persistence model.

D'Amico, Guglielmo; Prattico, Flavio

2013-01-01T23:59:59.000Z

164

Probability Distributions and Threshold Selection for Monte Carlo–Type Tropical Cyclone Wind Speed Forecasts  

Science Journals Connector (OSTI)

Probabilistic wind speed forecasts for tropical cyclones from Monte Carlo–type simulations are assessed within a theoretical framework for a simple unbiased Gaussian system that is based on feature size and location error that mimic tropical ...

Michael E. Splitt; Steven M. Lazarus; Sarah Collins; Denis N. Botambekov; William P. Roeder

2014-10-01T23:59:59.000Z

165

Estimation of sector roughness lengths and the effect on prediction of the vertical wind speed profile  

Science Journals Connector (OSTI)

An estimate of roughness length is required by some atmospheric models and is also used in the logarithmic profile to determine the increase of wind speed with height under neutral conditions. The choice ... thei...

R. J. Barthelmie; J. P. Palutikof; T. D. Davies

1993-10-01T23:59:59.000Z

166

Wind direction modelling using multiple observation points  

Science Journals Connector (OSTI)

...gains in the produced output power. chaos engineering|wind forecasting|multiple measurements...realized that the modelling of power output in wind turbines needs to be performed...region; in region 3, for high winds, the power output is subject to a threshold...

2008-01-01T23:59:59.000Z

167

WIND DATA REPORT Ragged Mt Maine  

E-Print Network [OSTI]

...................................................................................................................... 8 Wind Speed Time Series............................................................................................................. 9 Wind Speed Distributions........................................................................................................... 9 Monthly Average Wind Speeds

Massachusetts at Amherst, University of

168

EVALUATION OF MODELS FOR THE VERTICAL EXTRAPOLATION OF WIND SPEED MEASUREMENTS AT OFFSHORE SITES  

E-Print Network [OSTI]

EVALUATION OF MODELS FOR THE VERTICAL EXTRAPOLATION OF WIND SPEED MEASUREMENTS AT OFFSHORE SITES important for offshore wind energy utilisation are discussed and tested: Four models for the surface tested with measurements from the offshore field measurement Rødsand by extrapolating the measured 10 m

Heinemann, Detlev

169

Dynamical Downscaling of Wind Speed in Complex Terrain Prone To Bora-Type Flows  

Science Journals Connector (OSTI)

The results of numerically modeled wind speed climate, a primary component of wind energy resource assessment in the complex terrain of Croatia, are given. For that purpose, dynamical downscaling of 10 yr (1992–2001) of the 40-yr ECMWF Re-Analysis ...

Kristian Horvath; Alica Baji?; Stjepan Ivatek-Šahdan

2011-08-01T23:59:59.000Z

170

Tractable Analytic Expressions for the Wind Speed Probability Density Functions Using Expansions of Orthogonal Polynomials  

Science Journals Connector (OSTI)

The use of the two-parameter Weibull function as an estimator of the wind speed probability density function (PDF) is known to be problematic when a high accuracy of fit is required, such as in the computation of the wind power density function. ...

Mark L. Morrissey; J. Scott Greene

2012-07-01T23:59:59.000Z

171

UNIVERSITY OF CALIFORNIA, Surface Wind Speed Distributions: Implications for Climate and Wind Power  

E-Print Network [OSTI]

and Wind Power DISSERTATION submitted in partial satisfaction of the requirements for the degree of DOCTOR . . . . . . . . . . . . . . . . . 19 1.3 Global Ocean Wind Power and Surface Layer Stability . . . . . . . . 23 1.3.1 Global Winds . . . . . . 27 1.4 Usable Offshore Wind Power . . . . . . . . . . . . . . . . . . . . . . . 31 1.4.1 Wind Turbine

Zender, Charles

172

Optimal Evolutionary Wind Turbine Placement in Wind Farms Considering New Models of Shape, Orography and Wind Speed Simulation  

Science Journals Connector (OSTI)

In this paper we present a novel evolutionary algorithm for optimal positioning of wind turbines in wind farms. We consider a realistic model for the wind farm, which includes orography, shape of the wind farm, s...

B. Saavedra-Moreno; S. Salcedo-Sanz…

2011-01-01T23:59:59.000Z

173

Euler-Bernoulli Implementation of Spherical Anemometers for High Wind Speed Calculations via Strain Gauges  

E-Print Network [OSTI]

New measuring methods continue to be developed in the field of wind anemometry for various environments subject to low-speed and high-speed flows, turbulent-present flows, and ideal and non-ideal flows. As a result, anemometry has taken different...

Castillo, Davis

2011-08-08T23:59:59.000Z

174

Wind speed equalization-based incoming wind classification by aggregating DFIGs  

Science Journals Connector (OSTI)

With the development of wind energy, it is necessary to develop equivalent models to represent dynamic behaviors of wind farms in power systems. The equivalent wind method is investigated for the aggregation o...

Zhaojun Meng; Feng Xue; Xueming Li

2013-06-01T23:59:59.000Z

175

Maximum power point tracking of permanent magnet wind turbines equipped with direct matrix converter  

Science Journals Connector (OSTI)

This paper presents a novel control method for Maximum Power Point Tracking of wind turbines (WTs) equipped with a Permanent Magnet Synchronous Generator (PMSG) and a Direct Matrix Converter (DMC). The method calculates the optimum wind turbine speed and maximizes the extracted power from wind turbine. This is done by Hill Climb Search method which is simple and does not need to know the generator parameters and no need to solve the complicated differential equations of generator. WT rotor speed is compared with its optimal value and then DMC controls WT until its rotor speed reaches its optimum value. Under this situation maximum power is extracted from WT and is injected to the grid with unity power factor. It is implemented by controlling the phase and the amplitude of the DMC output voltage by Venturini switching method. Simulations are done on a 2?MW PMSG WT in MATLAB/SIMULINK to obtain the results the wind speed was varied both using the Van Der Hoven method and changing the wind step. The obtained results verify the accuracy and simplicity of proposed method.

2014-01-01T23:59:59.000Z

176

Spatial Variation and Interpolation of Wind Speed Statistics and Its Implication in Design Wind Load.  

E-Print Network [OSTI]

??Consideration of wind load is important for design of engineered structures. Codification of wind load for structural design requires the estimation of the quantiles or… (more)

Ye, Wei

2013-01-01T23:59:59.000Z

177

Unexpected vertical wind speed profiles in the boundary layer over the southern North Sea  

Science Journals Connector (OSTI)

Abstract Shallow atmospheric internal boundary layers over the southern part of the North Sea are common. Analysis of one year of meteorological data from the FINO1 research platform in the German Bight reveals that vertical wind speed profiles frequently do not conform to the expected modified logarithmic profile of Monin–Obukhov similarity theory. The wind profiles are mostly characterized by local maxima or kinks within the first 100 m over the sea surface. The data reveals the most frequent occurrence of a single maximum, but multiple maxima are often present, and there are sometimes even reversed profiles with the wind speed decreasing with height. The expected modified logarithmic profile occurs for a minority of cases. The evidence suggests the frequent presence of internal boundary layers that propagate from coastal land masses that surround the North Sea. A census of vertical wind speed profiles is presented that shows how different inflection states are linked with wind speed and atmospheric stability. The kinks are most prevalent in the upper part of the measurement range near the 100 m hub height of modern offshore the wind turbines, so that internal boundary layers represent a possible concern for the offshore wind energy industry in the North Sea region.

Anthony J. Kettle

2014-01-01T23:59:59.000Z

178

100-Year Return Value Estimates for Ocean Wind Speed and Significant Wave Height from the ERA-40 Data  

E-Print Network [OSTI]

and time variability of significant wave height and wind speed on the prediction of their extreme values of this dataset makes it ideal for the study of extreme wind and wave phenomena over the whole globe. Initial100-Year Return Value Estimates for Ocean Wind Speed and Significant Wave Height from the ERA-40

Haak, Hein

179

Fixed-Speed and Variable-Slip Wind Turbines Providing Spinning Reserves to the Grid: Preprint  

SciTech Connect (OSTI)

As the level of wind penetration increases, wind turbine technology must move from merely generating power from wind to taking a role in supporting the bulk power system. Wind turbines should have the capability to provide inertial response and primary frequency (governor) response so they can support the frequency stability of the grid. To provide governor response, wind turbines should be able to generate less power than the available wind power and hold the rest in reserve, ready to be accessed as needed. This paper explores several ways to control wind turbine output to enable reserve-holding capability. This paper focuses on fixed-speed (also known as Type 1) and variable-slip (also known as Type 2) turbines.

Muljadi, E.; Singh, M.; Gevorgian, V.

2012-11-01T23:59:59.000Z

180

The Influence of Boundary Layer Processes on the Diurnal Variation of the Climatological Near-Surface Wind Speed Probability Distribution over Land  

Science Journals Connector (OSTI)

Knowledge of the diurnally varying land surface wind speed probability distribution is essential for surface flux estimation and wind power management. Global observations indicate that the surface wind speed probability density function (PDF) is ...

Yanping He; Norman A. McFarlane; Adam H. Monahan

2012-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Adaptive pitch control for variable speed wind turbines  

DOE Patents [OSTI]

An adaptive method for adjusting blade pitch angle, and controllers implementing such a method, for achieving higher power coefficients. Average power coefficients are determined for first and second periods of operation for the wind turbine. When the average power coefficient for the second time period is larger than for the first, a pitch increment, which may be generated based on the power coefficients, is added (or the sign is retained) to the nominal pitch angle value for the wind turbine. When the average power coefficient for the second time period is less than for the first, the pitch increment is subtracted (or the sign is changed). A control signal is generated based on the adapted pitch angle value and sent to blade pitch actuators that act to change the pitch angle of the wind turbine to the new or modified pitch angle setting, and this process is iteratively performed.

Johnson, Kathryn E. (Boulder, CO); Fingersh, Lee Jay (Westminster, CO)

2012-05-08T23:59:59.000Z

182

Passively cooled direct drive wind turbine  

DOE Patents [OSTI]

A wind turbine is provided that passively cools an electrical generator. The wind turbine includes a plurality of fins arranged peripherally around a generator house. Each of the fins being oriented at an angle greater than zero degrees to allow parallel flow of air over the fin. The fin is further tapered to allow a constant portion of the fin to extend beyond the air stream boundary layer. Turbulence initiators on the nose cone further enhance heat transfer at the fins.

Costin, Daniel P. (Chelsea, VT)

2008-03-18T23:59:59.000Z

183

WIND SPEED AND ATMOSPHERIC STABILITY TRENDS FOR SELECTED UNITED STATES SURFACE STATIONS  

SciTech Connect (OSTI)

Recently it has been suggested that global warming and a decrease in mean wind speeds over most land masses are related. Decreases in near surface wind speeds have been reported by previous investigators looking at records with time spans of 15 to 30 years. This study focuses on United States (US) surface stations that have little or no location change since the late 1940s or the 1950s--a time range of up to 58 years. Data were selected from 62 stations (24 of which had not changed location) and separated into ten groups for analysis. The group's annual averages of temperature, wind speed, and percentage of Pasquill-Gifford (PG) stability categories were fitted with linear least squares regression lines. The results showed that the temperatures have increased for eight of the ten groups as expected. Wind speeds have decreased for nine of the ten groups. The mean slope of the wind speed trend lines for stations within the coterminous US was -0.77 m s{sup -1} per century. The percentage frequency of occurrence for the neutral (D) PG stability category decreased, while that for the unstable (B) and the stable (F) categories increased in almost all cases except for the group of stations located in Alaska.

Buckley, R; Allen H. Weber, A

2006-11-01T23:59:59.000Z

184

Optimal control for variable-speed wind generation systems using General Regression Neural Network  

Science Journals Connector (OSTI)

Abstract An induction generator (IG) speed drive with the application of an optimal controller and a proposed General Regression Neural Network (GRNN) controller is introduced in this paper. Grid connected wind energy conversion system (WECS) present interesting control demands, due to the intrinsic nonlinear characteristic of wind mills and electric generators. The GRNN with adaptive ant colony optimization (AACO) torque compensation is feed-forward to increase the robustness of the wind driven induction generator system. An optimal control loop for the wind power system is designed. The optimality of the whole system is defined in relation with the trade-off between the wind energy conversion maximization and the minimization of the induction generator torque variation that is responsible for the frequency fluctuations. This is achieved by using a combined optimization criterion, resulting in a LQ tracking problem with an infinite horizon and a measurable exogenous variable (wind speed). The proposed controller is designed to drive the turbine speed to extract maximum power from the wind and adjust to the power regulation.

Chih-Ming Hong; Fu-Sheng Cheng; Chiung-Hsing Chen

2014-01-01T23:59:59.000Z

185

Probabilistic Forecasts of Wind Speed: Ensemble Model Output Statistics  

E-Print Network [OSTI]

. Over the past two decades, ensembles of numerical weather prediction (NWP) models have been developed and phrases: Continuous ranked probability score; Density forecast; Ensem- ble system; Numerical weather prediction; Heteroskedastic censored regression; Tobit model; Wind energy. 1 #12;1 Introduction Accurate

Washington at Seattle, University of

186

Intense and Extreme Wind Speeds Observed by Anemometer and Seismic Networks: An Eastern U.S. Case Study  

Science Journals Connector (OSTI)

The scale and intensity of extreme wind events have tremendous relevance to determining the impact on infrastructure and natural and managed ecosystems. Analyses presented herein show the following. 1) Wind speeds in excess of the station-specific ...

S. C. Pryor; R. Conrick; C. Miller; J. Tytell; R. J. Barthelmie

2014-11-01T23:59:59.000Z

187

Wind speed modeled as a semi-Markov process with memory  

E-Print Network [OSTI]

The increasing interest in renewable energy, particularly in wind, has given rise to the necessity of accurate models for the generation of good synthetic wind speed data. Markov chains are often used with this purpose but better models are needed to reproduce the statistical properties of wind speed data. In a previous paper we showed that semi-Markov processes are more appropriate for this purpose but to reach an accurate reproduction of real data features high order model should be used. In this work we introduce an indexed semi-Markov process that is able to fit real data. We downloaded a database, freely available from the web, in which are included wind speed data taken from L.S.I. -Lastem station (Italy) and sampled every 10 minutes. We then generate synthetic time series for wind speed by means of Monte Carlo simulations. The time lagged autocorrelation is then used to compare statistical properties of the proposed model with those of real data and also with a synthetic time series generated though a ...

D'Amico, Guglielmo; Prattico, Flavio

2012-01-01T23:59:59.000Z

188

On the relationship between temperature and wind speed in the atmospheric surface layer  

E-Print Network [OSTI]

LIBRAR& A AN m os??E " "" ON THE RELATIONSHIP BETWEEN T" MP. "RATURE AND WIND SPEED IN THE ATMOSPHERIC SURFACE LAYER A Thesis John Me Pierrard Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial... logarithmically with height+ Also, the choice of a method of determination of the roughness length must be governed by an awareness of possible errors in the wind speed meas- urementso The system used to collect the data employed in this study is susceptible...

Pierrard, John Martin

2012-06-07T23:59:59.000Z

189

The Influence of Boundary Layer Processes on the Diurnal Variation of the Climatological Near-Surface Wind Speed Probability Distribution over Land*  

E-Print Network [OSTI]

diurnally varying vertical structure of the leading three climatological moments of near-surface wind speed-Surface Wind Speed Probability Distribution over Land* YANPING HE School of Earth and Ocean Sciences wind speed probability distribution is essential for surface flux estimation and wind power management

He, Yanping

190

Creating Synthetic Wind Speed Time Series for 15 New Zealand Wind Farms  

Science Journals Connector (OSTI)

Wind data at time scales from 10 min to 1 h are an important input for modeling the performance of wind farms and their impact on many countries’ national electricity systems. Planners need long-term realistic (i.e., meteorologically spatially and ...

Richard Turner; Xiaogu Zheng; Neil Gordon; Michael Uddstrom; Greg Pearson; Rilke de Vos; Stuart Moore

2011-12-01T23:59:59.000Z

191

Documenting Wind Speed and Power Deficits behind a Utility-Scale Wind Turbine  

Science Journals Connector (OSTI)

High-spatial-and-temporal-resolution radial velocity measurements surrounding a single utility-scale wind turbine were collected using the Texas Tech University Ka-band mobile research radars. The measurements were synthesized to construct the ...

Brian D. Hirth; John L. Schroeder

2013-01-01T23:59:59.000Z

192

High resolution reanalysis of wind speeds over the British Isles for wind energy integration   

E-Print Network [OSTI]

The UK has highly ambitious targets for wind development, particularly offshore, where over 30GW of capacity is proposed for development. Integrating such a large amount of variable generation presents enormous challenges. ...

Hawkins, Samuel Lennon

2012-11-29T23:59:59.000Z

193

ON THE ORIGIN OF THE SLOW SPEED SOLAR WIND: HELIUM ABUNDANCE VARIATIONS  

SciTech Connect (OSTI)

The first ionization potential (FIP) effect is the by now well-known enhancement in abundance over photospheric values of Fe and other elements with FIP below about 10 eV observed in the solar corona and slow speed solar wind. In our model, this fractionation is achieved by means of the ponderomotive force, arising as Alfven waves propagate through or reflect from steep density gradients in the solar chromosphere. This is also the region where low FIP elements are ionized, and high FIP elements are largely neutral leading to the fractionation as ions interact with the waves but neutrals do not. Helium, the element with the highest FIP and consequently the last to remain neutral as one moves upward, can be depleted in such models. Here, we investigate this depletion for varying loop lengths and magnetic field strengths. Variations in this depletion arise as the concentration of the ponderomotive force at the top of the chromosphere varies in response to Alfven wave frequency with respect to the resonant frequency of the overlying coronal loop, the magnetic field, and possibly also the loop length. We find that stronger depletions of He are obtained for weaker magnetic field, at frequencies close to or just above the loop resonance. These results may have relevance to observed variations of the slow wind solar He abundance with wind speed, with slower slow speed solar wind having a stronger depletion of He.

Rakowski, Cara E.; Laming, J. Martin [Space Science Division, Naval Research Laboratory Code 7674L, Washington, DC 20375 (United States)

2012-07-20T23:59:59.000Z

194

Novel sensorless generator control and grid fault ride-through strategies for variable-speed wind turbines and implementation on a new real-time simulation platform.  

E-Print Network [OSTI]

??The usage of MW-size variable-speed wind turbines as sources of energy has increased significantly during the last decade. Advantages over fixed-speed wind turbines include more… (more)

Yang, Sheng

2010-01-01T23:59:59.000Z

195

WORM: A new open road line source model for low wind speed conditions  

Science Journals Connector (OSTI)

Emission from road traffic constitutes one of the most important sources of air pollution in urban areas. This paper describes a newly developed air pollution dispersion model for open roads and highways called WORM (Weak Wind Open Road Model), and give some results using this model at Nordbysletta, Norway, in the period 1 January 200215 April 2002. Generally, a good correspondence was found between observed and model-predicted concentrations of nitrogen oxides (NOx), even in periods with low wind speed and (strongly) stable atmospheric conditions.

S.E. Walker

2011-01-01T23:59:59.000Z

196

The Effect of Magnetic Field Tilt and Divergence on the Mass Flux and Flow Speed in a Line-Driven Stellar Wind  

E-Print Network [OSTI]

We carry out an extended analytic study of how the tilt and faster-than-radial expansion from a magnetic field affect the mass flux and flow speed of a line-driven stellar wind. A key motivation is to reconcile results of numerical MHD simulations with previous analyses that had predicted non-spherical expansion would lead to a strong speed enhancement. By including finite-disk correction effects, a dynamically more consistent form for the non-spherical expansion, and a moderate value of the line-driving power index $\\alpha$, we infer more modest speed enhancements that are in good quantitative agreement with MHD simulations, and also are more consistent with observational results. Our analysis also explains simulation results that show the latitudinal variation of the surface mass flux scales with the square of the cosine of the local tilt angle between the magnetic field and the radial direction. Finally, we present a perturbation analysis of the effects of a finite gas pressure on the wind mass loss rate and flow speed in both spherical and magnetic wind models, showing that these scale with the ratio of the sound speed to surface escape speed, $a/v_{esc}$, and are typically 10-20% compared to an idealized, zero-gas-pressure model.

Stan Owocki; Asif ud-Doula

2003-10-07T23:59:59.000Z

197

Fig. 1. One hour measured irradiance and wind speed data with 0.2 seconds, 3 seconds and 1 minute (interpolated) sampling time.  

E-Print Network [OSTI]

Fig. 1. One hour measured irradiance and wind speed data with 0.2 seconds, 3 seconds and 1 minute of the solar irradiance and wind speed in fast changing conditions on the utility grid. This work proposes of resolution of the solar irradiance G [W/m2 ], ambient temperature Ta [K] and wind speed v [m/s] on a study

Sera, Dezso

198

Detecting and evaluating climate change effect on frequency analysis of wind speed  

Science Journals Connector (OSTI)

The purpose of this study is to detect an existing trend in wind speed and to evaluate the effect of climate change on frequency analysis of wind speed in Iran. Twenty-two stations with a length of records higher than 50 years have been selected. Five statistical methods that were used to detect the trends are Mann-Kendall, Spearman-Conley, cumulative deviation, autocorrelation coefficient and regression analysis. It is revealed that 11 stations have a positive or a negative trend while the rest has no trend. Climate change leads to a lack of homogeneity in a number of stations. Therefore, it is impossible to use frequency analysis for those stations. One appropriate approach is dividing the stations into two smaller parts, and for each part, frequency analysis could be taken if the part is homogenous.

Saeid Eslamian; Hadi Hassanzadeh; Mohammad Javad Khordadi

2009-01-01T23:59:59.000Z

199

A Coral Reefs Optimization algorithm with Harmony Search operators for accurate wind speed prediction  

Science Journals Connector (OSTI)

Abstract This paper introduces a new hybrid bio-inspired solver which combines elements from the recently proposed Coral Reefs Optimization (CRO) algorithm with operators from the Harmony Search (HS) approach, which gives rise to the coined CRO-HS optimization technique. Specifically, this novel bio-inspired optimizer is utilized in the context of short-term wind speed prediction as a means to obtain the best set of meteorological variables to be input to a neural Extreme Learning Machine (ELM) network. The paper elaborates on the main characteristics of the proposed scheme and discusses its performance when predicting the wind speed based on the measures of two meteorological towers located in USA and Spain. The good results obtained in these experiments when compared to naďve versions of the CRO and HS algorithms are promising and pave the way towards the utilization of the derived hybrid solver in other optimization problems arising from diverse disciplines.

S. Salcedo-Sanz; A. Pastor-Sánchez; J. Del Ser; L. Prieto; Z.W. Geem

2015-01-01T23:59:59.000Z

200

Log-normal distribution based EMOS models for probabilistic wind speed forecasting  

E-Print Network [OSTI]

Ensembles of forecasts are obtained from multiple runs of numerical weather forecasting models with different initial conditions and typically employed to account for forecast uncertainties. However, biases and dispersion errors often occur in forecast ensembles, they are usually under-dispersive and uncalibrated and require statistical post-processing. We present an Ensemble Model Output Statistics (EMOS) method for calibration of wind speed forecasts based on the log-normal (LN) distribution, and we also show a regime-switching extension of the model which combines the previously studied truncated normal (TN) distribution with the LN. Both presented models are applied to wind speed forecasts of the eight-member University of Washington mesoscale ensemble, of the fifty-member ECMWF ensemble and of the eleven-member ALADIN-HUNEPS ensemble of the Hungarian Meteorological Service, and their predictive performances are compared to those of the TN and general extreme value (GEV) distribution based EMOS methods an...

Baran, Sándor

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
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201

Beyond 10 Km Range wind-speed measurement with a 1.5 µm all-fiber laser source  

Science Journals Connector (OSTI)

We report the development of a high power single-frequency all-fiber laser for long-range wind speed measurement. The laser source has been integrated in a Lidar architecture and we...

Renard, William; Goular, Didier; Valla, Matthieu; Planchat, Christophe; Augere, Beatrice; Dolfi-Bouteyre, Agnes; Besson, Claudine; Canat, Guillaume

202

Glacial Cooling in the Tropics: Exploring the Roles of Tropospheric Water Vapor, Surface Wind Speed, and Boundary Layer Processes  

Science Journals Connector (OSTI)

This paper is a modeling study of possible roles for tropospheric water vapor, surface wind speed, and boundary layer processes in glacial cooling in the Tropics. The authors divide the Tropics into a region of persistent deep convection and a ...

Richard Seager; Amy C. Clement; Mark A. Cane

2000-07-01T23:59:59.000Z

203

Correlated solar wind speed, density, and magnetic field changes at J. D. Richardson and C. Wang1  

E-Print Network [OSTI]

Correlated solar wind speed, density, and magnetic field changes at Voyager 2 J. D. Richardson and C. Wang1 Center for Space Research, Massachusetts Institute of Technology, Cambridge, Massachusetts December 2003. [1] The character of the solar wind plasma data observed by Voyager 2 recently changed

Richardson, John

204

RESEARCH ARTICLE Controlling speed and direction during interception  

E-Print Network [OSTI]

. Turning rate was controlled using a steering wheel and speed was controlled using a foot pedal (Wann and Land 2000), braking (Lee 1976; Yilmaz and Warren 1995), and fly ball catching (Chapman 1968

205

Occurrence of high-speed solar wind streams over the Grand Modern Maximum  

E-Print Network [OSTI]

In the declining phase of the solar cycle, when the new-polarity fields of the solar poles are strengthened by the transport of same-signed magnetic flux from lower latitudes, the polar coronal holes expand and form non-axisymmetric extensions toward the solar equator. These extensions enhance the occurrence of high-speed solar wind streams (HSS) and related co-rotating interaction regions in the low-latitude heliosphere, and cause moderate, recurrent geomagnetic activity in the near-Earth space. Here, using a novel definition of geomagnetic activity at high (polar cap) latitudes and the longest record of magnetic observations at a polar cap station, we calculate the annually averaged solar wind speeds as proxies for the effective annual occurrence of HSS over the whole Grand Modern Maximum (GMM) from 1920s onwards. We find that a period of high annual speeds (frequent occurrence of HSS) occurs in the declining phase of each solar cycle 16-23. For most cycles the HSS activity clearly maximizes during one year...

Mursula, Kalevi; Holappa, Lauri

2015-01-01T23:59:59.000Z

206

BBO-based small autonomous hybrid power system optimization incorporating wind speed and solar radiation forecasting  

Science Journals Connector (OSTI)

Abstract Rising carbon emission or carbon footprint imposes grave concern over the earth?s climatic condition, as it results in increasing average global temperature. Renewable energy sources seem to be the favorable solution in this regard. It can reduce the overall energy consumption rate globally. However, the renewable sources are intermittent in nature with very high initial installation price. Off-grid Small Autonomous Hybrid Power Systems (SAHPS) are good alternative for generating electricity locally in remote areas, where the transmission and distribution of electrical energy generated from conventional sources are otherwise complex, difficult and costly. In optimizing SAHPS, weather data over past several years are generally the main input, which include wind speed and solar radiation. The weather resources used in this optimization process have unsystematic variations based on the atmospheric and seasonal phenomenon and it also varies from year to year. While using past data in the analysis of SAHPS performance, it was assumed that the same pattern will be followed in the next year, which in reality is very unlikely to happen. In this paper, we use BBO optimization algorithm for SAHPS optimal component sizing by minimizing the cost of energy. We have also analysed the effect of using forecast weather data instead of past data on the SAHPS performance. ANNs, which are trained with back-propagation training algorithm, are used for wind speed and solar radiation forecasting. A case study was used for demonstrating the performance of BBO optimization algorithm along with forecasting effects. The simulation results clearly showed the advantages of utilizing wind speed and solar radiation forecasting in a SAHPS optimization problem.

R.A. Gupta; Rajesh Kumar; Ajay Kumar Bansal

2015-01-01T23:59:59.000Z

207

Effect of Tip-Speed Constraints on the Optimized Design of a Wind Turbine  

SciTech Connect (OSTI)

This study investigates the effect of tip-velocity constraints on system levelized cost of energy (LCOE). The results indicate that a change in maximum tip speed from 80 to 100~m/s could produce a 32% decrease in gearbox weight (a 33% reduction in cost) which would result in an overall reduction of 1%-9% in system LCOE depending on the design approach. Three 100~m/s design cases were considered including a low tip-speed ratio/high-solidity rotor design, a high tip-speed ratio/ low-solidity rotor design, and finally a flexible blade design in which a high tip-speed ratio was used along with removing the tip deflection constraint on the rotor design. In all three cases, the significant reduction in gearbox weight caused by the higher tip-speed and lower overall gear ratio was counterbalanced by increased weights for the rotor and/or other drivetrain components and the tower. As a result, the increased costs of either the rotor or drivetrain components offset the overall reduction in turbine costs from down-sizing the gearbox. Other system costs were not significantly affected, whereas energy production was slightly reduced in the 100~m/s case low tip-speed ratio case and increased in the high tip-speed ratio case. This resulted in system cost of energy reductions moving from the 80~m/s design to the 100~m/s designs of 1.2% for the low tip-speed ratio, 4.6% for the high tip-speed ratio, and 9.5% for the final flexible case (the latter result is optimistic because the impact of deflection of the flexible blade on power production was not modeled). Overall, the results demonstrate that there is a trade-off in system design between the maximum tip velocity and the overall wind plant cost of energy, and there are many trade-offs within the overall system in designing a turbine for a high maximum tip velocity.

Dykes, K.; Resor, B.; Platt, A.; Guo, Y.; Ning, A.; King, R.; Parsons, T.; Petch, D.; Veers, P.

2014-10-01T23:59:59.000Z

208

Coronal Heating and Acceleration of the High/Low-Speed Solar Wind by Fast/Slow MHD Shock Trains  

E-Print Network [OSTI]

We investigate coronal heating and acceleration of the high- and low-speed solar wind in the open field region by dissipation of fast and slow magnetohydrodynamical (MHD) waves through MHD shocks. Linearly polarized \\Alfven (fast MHD) waves and acoustic (slow MHD) waves travelling upwardly along with a magnetic field line eventually form fast switch-on shock trains and hydrodynamical shock trains (N-waves) respectively to heat and accelerate the plasma. We determine one dimensional structure of the corona from the bottom of the transition region (TR) to 1AU under the steady-state condition by solving evolutionary equations for the shock amplitudes simultaneously with the momentum and proton/electron energy equations. Our model reproduces the overall trend of the high-speed wind from the polar holes and the low-speed wind from the mid- to low-latitude streamer except the observed hot corona in the streamer. The heating from the slow waves is effective in the low corona to increase the density there, and plays an important role in the formation of the dense low-speed wind. On the other hand, the fast waves can carry a sizable energy to the upper level to heat the outer corona and accelerate the high-speed wind effectively. We also study dependency on field strength, $B_0$, at the bottom of the TR and non-radial expansion of a flow tube, $f_{\\rm max}$, to find that large $B_0/f_{\\rm max}\\gtrsim 2$ but small $B_0\\simeq 2$G are favorable for the high-speed wind and that small $B_0/f_{\\rm max}\\simeq 1$ is required for the low-speed wind.

Takeru K. Suzuki

2003-12-22T23:59:59.000Z

209

A data mining approach: Analyzing wind speed and insolation period data in Turkey for installations of wind and solar power plants  

Science Journals Connector (OSTI)

Wind and solar power plant installations have been recently increased rapidly with respect to the depletion of fossil-based fuels all over the world. Due to stochastic nature of meteorological conditions, wind and solar energies have a non-schedulable nature and they require several installation analyses to determine the location and the capacities of wind and solar power to be produced. This paper focuses on the similarity, feasibility and numerical analyses of 75 cities in Turkey based on the monthly average wind speed and insolation period data. The nearest and the farest neighbor algorithms are used as agglomerative hierarchical clustering methods with Euclidean, Manhattan and Minkowski distance metrics in the stage of making the similarity and feasibility analyses. The maximum cophenetic correlation coefficient is achieved by the nearest neighbor algorithm with the Minkowski distance metric in the similarity and feasibility analyses. On the other hand, graphical representations of the monthly average wind speed and insolation period data are utilized for making the numerical analysis. The highest annual average wind speed and insolation period are obtained as 3.88 m/s and 8.45 h/day, respectively. Overall, many inferences were achieved in acceptable and efficient limits for wind and solar energy.

Ilhami Colak; Seref Sagiroglu; Mehmet Demirtas; Mehmet Yesilbudak

2013-01-01T23:59:59.000Z

210

Dependence of Solar-Wind Power Spectra on the Direction of the Local Mean Magnetic Field  

Science Journals Connector (OSTI)

Wavelet analysis can be used to measure the power spectrum of solar-wind fluctuations along a line in any direction (?, ) with respect to the local mean magnetic field B 0. This technique is applied to study solar-wind turbulence in high-speed streams in the ecliptic plane near solar minimum using magnetic field measurements with a cadence of eight vectors per second. The analysis of nine high-speed streams shows that the reduced spectrum of magnetic field fluctuations (trace power) is approximately azimuthally symmetric about B 0 in both the inertial range and dissipation range; in the inertial range the spectra are characterized by a power-law exponent that changes continuously from 1.6 ± 0.1 in the direction perpendicular to the mean field to 2.0 ± 0.1 in the direction parallel to the mean field. The large uncertainties suggest that the perpendicular power-law indices 3/2 and 5/3 are both consistent with the data. The results are similar to those found by Horbury et al. at high heliographic latitudes. Comparisons between solar-wind observations and the theories of strong incompressible MHD turbulence developed by Goldreich & Sridhar and Boldyrev are not rigorously justified because these theories only apply to turbulence with vanishing cross-helicity although the normalized cross-helicity of solar-wind turbulence is not negligible. Assuming these theories can be generalized in such a way that the three-dimensional wavevector spectra have similar functional forms when the cross-helicity is nonzero, then for the interval of Ulysses data analyzed by Horbury et al. the ratio of the spectra perpendicular and parallel to B 0 is more consistent with the Goldreich & Sridhar scaling P ?/P ? ? ?1/3 than with the Boldyrev scaling ?1/2. The analysis of high-speed streams in the ecliptic plane does not yield a reliable measurement of this scaling law. The transition from a turbulent MHD-scale energy cascade to a kinetic Alfvén wave (KAW) cascade occurs when k ?? i 1, which coincides with the spectral break. At slightly higher wavenumbers, in the dissipation range, there is a peak in the power ratio with P ?/P ? 1. The decay of this peak may be caused by the damping of KAWs, which is predicted to occur near k ?? i 4.

J. J. Podesta

2009-01-01T23:59:59.000Z

211

Wind Effect, Recirculation and Thermal Flow Field of a Direct Air?cooled Condenser for a Large Power Plant  

Science Journals Connector (OSTI)

The thermal effect experiments were carried out of a direct air?cooled system in the low speed wind tunnel. The influence of effect factors on recirculation is also discussion after that the relationship between the thermal flow field structure and recirculation ratio under the cooling tower is analyzed. At last the engineering measures to reduce or avoid recirculation are proposed. For certain conditions the experimental measurement shows close agreement with numerical values.

W. L. Zhao; P. Q. Liu; H. S. Duan; J. Y. Zhu

2011-01-01T23:59:59.000Z

212

A wind-tunnel investigation of the wind speed and turbulence characteristics close to the ground over various escarpment shapes  

Science Journals Connector (OSTI)

A wind-tunnel investigation of the wind flow over two-dimensional forward-facing escarpments ... into the effects of local topography on the wind flow close to the ground. Four sharp ... -wire anemometer. The mod...

A. J. Bowen; D. Lindley

1977-10-01T23:59:59.000Z

213

Vertical axis wind turbine  

SciTech Connect (OSTI)

Wind turbines are largely divided into vertical axis wind turbines and propeller (Horizontal axis) wind turbines. The present invention discloses a vertical axis high speed wind turbine provided with rotational speed control systems. This vertical axis wind turbine is formed by having blades of a proper airfoil fitted to respective supporting arms provided radially from a vertical rotating shaft by keeping the blade span-wise direction in parallel with the shaft and being provided with aerodynamic control elements operating manually or automatically to control the rotational speed of the turbine.

Kato, Y.; Seki, K.; Shimizu, Y.

1981-01-27T23:59:59.000Z

214

EVOLUTION OF THE RELATIONSHIPS BETWEEN HELIUM ABUNDANCE, MINOR ION CHARGE STATE, AND SOLAR WIND SPEED OVER THE SOLAR CYCLE  

SciTech Connect (OSTI)

The changing relationships between solar wind speed, helium abundance, and minor ion charge state are examined over solar cycle 23. Observations of the abundance of helium relative to hydrogen (A{sub He} {identical_to} 100 Multiplication-Sign n{sub He}/n{sub H}) by the Wind spacecraft are used to examine the dependence of A{sub He} on solar wind speed and solar activity between 1994 and 2010. This work updates an earlier study of A{sub He} from 1994 to 2004 to include the recent extreme solar minimum and broadly confirms our previous result that A{sub He} in slow wind is strongly correlated with sunspot number, reaching its lowest values in each solar minima. During the last minimum, as sunspot numbers reached their lowest levels in recent history, A{sub He} continued to decrease, falling to half the levels observed in slow wind during the previous minimum and, for the first time observed, decreasing even in the fastest solar wind. We have also extended our previous analysis by adding measurements of the mean carbon and oxygen charge states observed with the Advanced Composition Explorer spacecraft since 1998. We find that as solar activity decreased, the mean charge states of oxygen and carbon for solar wind of a given speed also fell, implying that the wind was formed in cooler regions in the corona during the recent solar minimum. The physical processes in the coronal responsible for establishing the mean charge state and speed of the solar wind have evolved with solar activity and time.

Kasper, J. C.; Stevens, M. L.; Korreck, K. E.; Maruca, B. A.; Kiefer, K. K. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Schwadron, N. A. [Institute for the Study of Earth, Oceans and Space, University of New Hampshire, Durham, NH 03824 (United States); Lepri, S. T. [Department of Atmospheric, Oceanic and Space Studies, University of Michigan, Ann Arbor, MI 48109 (United States)

2012-02-01T23:59:59.000Z

215

Cross-Spectrum of Wind Speed for Meso-Gamma Scales in the Upper Surface Layer over South-Eastern Australia  

Science Journals Connector (OSTI)

Analytical expressions for the cross-spectrum of wind speed are developed for the stochastic simulation of wind power in south-eastern Australia. The expressions...?1.... The influence of site separation distance...

Milton J. Woods; Robert J. Davy; Christopher J. Russell…

2011-10-01T23:59:59.000Z

216

Effect of fluctuating wind direction on cross natural ventilation in buildings from large eddy simulation  

E-Print Network [OSTI]

wind direction, and the simulated results agree reasonably with the corresponding experimental data is the use of small-scale models in a wind tunnel to simulate natural ventilation. In general, the mean flow1 Effect of fluctuating wind direction on cross natural ventilation in buildings from large eddy

Chen, Qingyan "Yan"

217

Damage measurements on the NWTC direct-drive, variable-speed test bed  

SciTech Connect (OSTI)

The NWTC (National Wind Technology Center) Variable-Speed Test Bed turbine is a three-bladed, 10-meter, downwind machine that can be run in either fixed-speed or variable-speed mode. In the variable-speed mode, the generator torque is regulated, using a discrete-stepped load bank to maximize the turbine`s power coefficient. At rated power, a second control loop that uses blade pitch to maintain rotor speed essentially as before, i.e., using the load bank to maintain either generator power or (optionally) generator torque. In this paper, the authors will use this turbine to study the effect of variable-speed operation on blade damage. Using time-series data obtained from blade flap and edge strain gauges, the load spectrum for the turbine is developed using rainflow counting techniques. Miner`s rule is then used to determine the damage rates for variable-speed and fixed-speed operation. The results illustrate that the controller algorithm used with this turbine introduces relatively large load cycles into the blade that significantly reduce its service lifetime, while power production is only marginally increased.

Sutherland, H.J. [Sandia National Lab., Albuquerque, NM (United States); Carlin, P.W. [National Renewable Energy Lab., Golden, CO (United States)

1998-12-31T23:59:59.000Z

218

Repetitive substorms caused by Alfvenic waves of the interplanetary magnetic field during high-speed solar wind streams  

E-Print Network [OSTI]

, but they may be locally generated from stream-stream interaction effects or amplified Alfve´n waves originating-speed solar wind streams D.-Y. Lee,1 L. R. Lyons,2 K. C. Kim,1 J.-H. Baek,3 K.-H. Kim,3 H.-J. Kim,1 J. Weygand wind streams, J. Geophys. Res., 111, A12214, doi:10.1029/2006JA011685. 1. Introduction [2] During

Lyons, Larry

219

Feature selection in wind speed prediction systems based on a hybrid coral reefs optimization – Extreme learning machine approach  

Science Journals Connector (OSTI)

Abstract This paper presents a novel approach for short-term wind speed prediction based on a Coral Reefs Optimization algorithm (CRO) and an Extreme Learning Machine (ELM), using meteorological predictive variables from a physical model (the Weather Research and Forecast model, WRF). The approach is based on a Feature Selection Problem (FSP) carried out with the CRO, that must obtain a reduced number of predictive variables out of the total available from the WRF. This set of features will be the input of an ELM, that finally provides the wind speed prediction. The CRO is a novel bio-inspired approach, based on the simulation of reef formation and coral reproduction, able to obtain excellent results in optimization problems. On the other hand, the ELM is a new paradigm in neural networks’ training, that provides a robust and extremely fast training of the network. Together, these algorithms are able to successfully solve this problem of feature selection in short-term wind speed prediction. Experiments in a real wind farm in the USA show the excellent performance of the CRO–ELM approach in this FSP wind speed prediction problem.

S. Salcedo-Sanz; A. Pastor-Sánchez; L. Prieto; A. Blanco-Aguilera; R. García-Herrera

2014-01-01T23:59:59.000Z

220

Decoding the Speed and Motion Direction of Moving Targets Using a Turtle Retinal Patch Model  

E-Print Network [OSTI]

Decoding the Speed and Motion Direction of Moving Targets Using a Turtle Retinal Patch Model of the Contents . . . . . . . . . . . . . . . . . . . . . . 2 2. The Turtle Retina . . . . . . . . . . . . . . . . . . . . . . . 7 2.3 Turtle Retina . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3. Retinal Model

Ghosh, Bijoy K.

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

General study of the control principles and dynamic fault behaviour of variable-speed wind turbine and wind farm generic models  

Science Journals Connector (OSTI)

Abstract The interest towards generic models or sometimes also called standard models of wind turbine generators (WTGs) is significantly increasing. Mainly due to their improved power quality, better controllability and higher power extraction capability, variable-speed wind turbines driving a synchronous or an induction machine are capturing the global market. Throughout this paper, dynamic modelling and performance analysis of the generic models of the variable-speed WTGs, namely the doubly-fed induction generator and the fully-rated converter based WTGs, are achieved using integration between Matlab/Simulink and PSCAD/EMTDC simulation platforms. Later on, the performance of type-4 wind turbine driving a permanent magnet synchronous machine is analysed during fault and then compared with the case when driving a wound rotor induction machine. The differences in control principles and dynamic fault behaviour are highlighted. Afterwards, investigations on wind farm level are accomplished. A case study during which the developed generic models and the generic model of the variable-speed machine are compared is conducted. Different arrangements for the construction of the generic wind farm are considered.

Tareq Saber Abuaisha

2014-01-01T23:59:59.000Z

222

Low Speed Virtual Wind Tunnel Simulation For Educational Studies In Introducing Computational Fluid Dynamics And Flow Visualization  

E-Print Network [OSTI]

, the Low Speed Virtual Wind Tunnel simulation is created. This program cuts down on the require information from the user in order to perform a simulation. The program is capable of taking an airfoil coordinates that is generated according to the user...

Yang, Cher-Chiang

2008-05-05T23:59:59.000Z

223

IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 23, NO. 2, JUNE 2008 551 Sliding Mode Power Control of Variable-Speed Wind  

E-Print Network [OSTI]

IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 23, NO. 2, JUNE 2008 551 Sliding Mode Power Control of Variable-Speed Wind Energy Conversion Systems Brice Beltran, Tarek Ahmed-Ali, and Mohamed El Hachemi in variable-speed wind energy conversion sys- tems (VS-WECS). These systems have two operation regions de

Paris-Sud XI, Université de

224

10MW Class Direct Drive HTS Wind Turbine, CRADA Number CRD-08...  

Office of Scientific and Technical Information (OSTI)

10MW Class Direct Drive HTS Wind Turbine Cooperative Research and Development Final Report CRADA Number: CRD-08-00312 NREL Technical Contact: Walter Musial CRADA Report NREL...

225

Application of Ensemble Sensitivity Analysis to Observation Targeting for Short-term Wind Speed Forecasting  

SciTech Connect (OSTI)

The operators of electrical grids, sometimes referred to as Balancing Authorities (BA), typically make critical decisions on how to most reliably and economically balance electrical load and generation in time frames ranging from a few minutes to six hours ahead. At higher levels of wind power generation, there is an increasing need to improve the accuracy of 0- to 6-hour ahead wind power forecasts. Forecasts on this time scale have typically been strongly dependent on short-term trends indicated by the time series of power production and meteorological data from a wind farm. Additional input information is often available from the output of Numerical Weather Prediction (NWP) models and occasionally from off-site meteorological towers in the region surrounding the wind generation facility. A widely proposed approach to improve short-term forecasts is the deployment of off-site meteorological towers at locations upstream from the wind generation facility in order to sense approaching wind perturbations. While conceptually appealing, it turns out that, in practice, it is often very difficult to derive significant benefit in forecast performance from this approach. The difficulty is rooted in the fact that the type, scale, and amplitude of the processes controlling wind variability at a site change from day to day if not from hour to hour. Thus, a location that provides some useful forecast information for one time may not be a useful predictor a few hours later. Indeed, some processes that cause significant changes in wind power production operate predominantly in the vertical direction and thus cannot be monitored by employing a network of sensors at off-site locations. Hence, it is very challenging to determine the type of sensors and deployment locations to get the most benefit for a specific short-term forecast application. Two tools recently developed in the meteorological research community have the potential to help determine the locations and parameters to measure in order to get the maximum positive impact on forecast performance for a particular site and short-term look-ahead period. Both tools rely on the use of NWP models to assess the sensitivity of a forecast for a particular location to measurements made at a prior time (i.e. the look-ahead period) at points surrounding the target location. The fundamental hypothesis is that points and variables with high sensitivity are good candidates for measurements since information at those points are likely to have the most impact on the forecast for the desired parameter, location and look-ahead period. One approach is called the adjoint method (Errico and Vukicevic, 1992; Errico, 1997) and the other newer approach is known as Ensemble Sensitivity Analysis (ESA; Ancell and Hakim 2007; Torn and Hakim 2008). Both approaches have been tested on large-scale atmospheric prediction problems (e.g. forecasting pressure or precipitation over a relatively large region 24 hours ahead) but neither has been applied to mesoscale space-time scales of winds or any other variables near the surface of the earth. A number of factors suggest that ESA is better suited for short-term wind forecasting applications. One of the most significant advantages of this approach is that it is not necessary to linearize the mathematical representation of the processes in the underlying atmospheric model as required by the adjoint approach. Such a linearization may be especially problematic for the application of short-term forecasting of boundary layer winds in complex terrain since non-linear shifts in the structure of boundary layer due to atmospheric stability changes are a critical part of the wind power production forecast problem. The specific objective of work described in this paper is to test the ESA as a tool to identify measurement locations and variables that have the greatest positive impact on the accuracy of wind forecasts in the 0- to 6-hour look-ahead periods for the wind generation area of California's Tehachapi Pass during the warm (high generation) season. The paper is organized

Zack, J; Natenberg, E; Young, S; Manobianco, J; Kamath, C

2010-02-21T23:59:59.000Z

226

Vertical axis wind turbine  

SciTech Connect (OSTI)

Wind turbines are largely divided into vertical axis wind turbines and propeller (Horizontal axis) wind turbines. The present invention discloses a vertical axis high speed wind turbine provided with a starting and braking control system. This vertical axis wind turbine is formed by having blades of a proper airfoil fitted to respective supporting arms provided radially from a vertical rotary axis by keeping the blade span-wise direction in parallel with the axis and being provided with a low speed control windmill in which the radial position of each operating piece varies with a centrifugal force produced by the rotation of the vertical rotary axis.

Kato, Y.; Seki, K.; Shimizu, Y.

1981-01-27T23:59:59.000Z

227

Microsoft PowerPoint - 4FO-6-Parker-BNL-Direct-Wind-Magnets.pptx  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * presented by Brett Parker, BNL-SMD presented by Brett Parker, BNL-SMD BNL Direct Wind Magnets * BNL Direct Wind Magnets * *In memory of Pat Thompson *In memory of Pat Thompson * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Outline: BNL Direct Wind Magnets * Overview production process and terminology. - Coil Winding, Wrapping, Measurement, and Curing - Planar Patterns versus Serpentine Coils - Multifunction, Multi-Layer Coils and Field Quality * Examples from past and current projects. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Examples from past and current projects. - ILC QD0 R&D Prototype and ATF2 Upgrade Magnets

228

Improving an Accuracy of ANN-Based Mesoscale-Microscale Coupling Model by Data Categorization: With Application to Wind Forecast for Offshore and Complex Terrain Onshore Wind Farms  

Science Journals Connector (OSTI)

The ANN-based mesoscale-microscale coupling model forecasts wind speed and wind direction with high accuracy for wind parks located in complex terrain onshore, yet some weather regimes remains unresolved and f...

Alla Sapronova; Catherine Meissner…

2014-01-01T23:59:59.000Z

229

Modelling the reorientation of sea-ice faults as the wind changes direction  

E-Print Network [OSTI]

in the Ant- arctic. As sea ice reflects up to 80% of incident solar radiation, insulates the ocean fromModelling the reorientation of sea-ice faults as the wind changes direction Alexander V. WILCHINSKY-1290, USA ABSTRACT. A discrete-element model of sea ice is used to study how a 908 change in wind direction

Feltham, Daniel

230

Choosing wind power plant locations and sizes based on electric reliability measures using multiple-year wind speed measurements  

SciTech Connect (OSTI)

To project the US potential to meet future electricity demands with wind energy, estimates of available wind resource and costs to access that resource are critical. The US Department of Energy (DOE) Energy Information Administration (EIA) annually estimates the US market penetration of wind in its Annual Energy Outlook series. For these estimates, the EIA uses wind resource data developed by the Pacific Northwest National Laboratory for each region of the country. However, the EIA multiplies the cost of windpower by several factors, some as large as 3, to account for resource quality, market factors associated with accessing the resource, electric grid impacts, and rapid growth in the wind industry. This paper examines the rationale behind these additional costs and suggests alternatives.

Milligan, M.R.; Artig, R.

1999-07-08T23:59:59.000Z

231

Direct and Inverse Cascades in the Wind-Driven Sea  

E-Print Network [OSTI]

We offer a new form for the S(nl) term in the Hasselmann kinetic equation for squared wave amplitudes of wind-driven gravity wave. This form of S(nl) makes possible to rewrite in differential form the conservation laws for energy, momentum, and wave action, and introduce their fluxes by a natural way. We show that the stationary kinetic equation has a family of exact Kolmogorov-type solutions governed by the fluxes of motion constants: wave action, energy, and momentum. The simple "local" model for S(nl) term that is equivalent to the "diffusion approximation" is studied in details. In this case, Kolmogorov spectra are found in the explicit form. We show that a general solution of the stationary kinetic equation behind the spectral peak is described by the Kolmogorov-type solution with frequency-dependent fluxes. The domains of "inverse cascade" and "direct cascade" can be separated by natural way. The spectrum in the universal domain is close to $\\omega^{-4}$.

Zakharov, Vladimir E

2015-01-01T23:59:59.000Z

232

Structure of Turbulence in Katabatic Flows below and above the Wind-Speed Maximum  

E-Print Network [OSTI]

Measurements of small-scale turbulence made over the complex-terrain atmospheric boundary layer during the MATERHORN Program are used to describe the structure of turbulence in katabatic flows. Turbulent and mean meteorological data were continuously measured at multiple levels at four towers deployed along the East lower slope (2-4 deg) of Granite Mountain. The multi-level observations made during a 30-day long MATERHORN-Fall field campaign in September-October 2012 allowed studying of temporal and spatial structure of katabatic flows in detail, and herein we report turbulence and their variations in katabatic winds. Observed vertical profiles show steep gradients near the surface, but in the layer above the slope jet the vertical variability is smaller. It is found that the vertical (normal to the slope) momentum flux and horizontal (along the slope) heat flux in a slope-following coordinate system change their sign below and above the wind maximum of a katabatic flow. The vertical momentum flux is directed...

Grachev, Andrey A; Di Sabatino, Silvana; Fernando, Harindra J S; Pardyjak, Eric R; Fairall, Christopher W

2015-01-01T23:59:59.000Z

233

Wind velocity measurements using a pulsed LIDAR system: first results  

E-Print Network [OSTI]

. A laser beam of 1.54 µm wavelength takes measurements of the wind speed in beamwise direction. To obtain the three-dimensinal wind vector, the beam is inclined by 30 from vertical direction and measurements 12345 t [s] vh[m/s] Figure 2. Segment of measured time series of the horizontal wind speed magnitude vh

Peinke, Joachim

234

Discrete sliding mode control strategy for direct real and reactive power regulation of wind driven DFIG  

Science Journals Connector (OSTI)

Abstract This paper investigates a discrete sliding mode control (DSMC) strategy for direct real and reactive power regulation for wind driven doubly fed induction generator (DFIG). The real and reactive power errors are eliminated by directly calculating the rotor control voltages through DSMC. In the stator stationary reference frame, direct real and reactive power control strategy is implemented. Therefore, it does not require the angular information of the stator and rotor currents or voltages. It does not involve any extra current loops which results into simple design. The use of constant converter switching frequency via space vector pulse width modulation eases the AC harmonic filter design and improves the power quality. The use of fast and flexible discrete controller makes the system competent with modern digital world. Detailed simulations have been carried out to validate the method. The simulation results reveal that the real and reactive power references are followed smoothly even in the presence of speed perturbations and performance of the system is robust against parameter variations and system disturbances.

V.N. Pande; U.M. Mate; Shailaja Kurode

2013-01-01T23:59:59.000Z

235

A study of wind speed modification and internal boundary-layer heights in a coastal region  

Science Journals Connector (OSTI)

Wind profile data within the first two kilometres of a coast have been used to study the wind field modification downstream of this surface discontinuity. The land area is generally very flat, having an overal...

Hans Bergström; Per-Erik Johansson; Ann-Sofi Smedman

1988-03-01T23:59:59.000Z

236

Lorentz transformation directly from the invariance of the speed of light via the addition law of parallel speeds  

E-Print Network [OSTI]

We show that starting with the addition law of parallel speeds derived as a consequence of the invariance of the speed of light, the Lorentz transformations for the space-time coordinates can be derived.

Bernhard Rothenstein

2007-09-14T23:59:59.000Z

237

Remote sensing of total integrated water vapor, wind speed, and cloud liquid water over the ocean using the Special Sensor Microwave/Imager (SSM/I)  

E-Print Network [OSTI]

A modified D-matrix retrieval method is the basis of the refined total integrated water vapor (TIWV), total integrated cloud liquid water (CLW), and surface wind speed (WS) retrieval methods that are developed. The 85 GHZ polarization difference...

Manning, Norman Willis William

2012-06-07T23:59:59.000Z

238

Wind Power | Open Energy Information  

Open Energy Info (EERE)

Wind Power Wind Power Jump to: navigation, search Wind Power WIndfarm.Sunset.jpg Wind power is a form of solar energy.[1] Wind is caused by the uneven heating of the atmosphere by the sun, variations in the earth's surface, and rotation of the earth. Mountains, bodies of water, and vegetation all influence wind flow patterns[2], [3]. Wind energy (or wind power) describes the process by which wind is used to generate electricity. Wind turbines convert the energy in wind to electricity by rotating propeller-like blades around a rotor. The rotor turns the drive shaft, which turns an electric generator.[2] Three key factors affect the amount of energy a turbine can harness from the wind: wind speed, air density, and swept area.[4] Mechanical power can also be utilized directly for specific tasks such as

239

Effect of wind speed on the growth of the upper convective zone in a solar pond  

E-Print Network [OSTI]

[2]. The distance which the wind has to act on the surface of a pond is commonly called fetch, or fetch length. The purpose of the nets or other devices used in wind suppression is to reduce the fetch and transmit some of the energy in the waves... to the sides of the pond. Wind mixing of the upper convective zone can be thought of as converting some of the kinetic energy in the wind to potential energy in the fluid by a process called entrainment. Entrainment is defined in detail in Chapter V...

McMinn, Steven Lee

2012-06-07T23:59:59.000Z

240

Definition: Wind rose | Open Energy Information  

Open Energy Info (EERE)

rose rose Jump to: navigation, search Dictionary.png Wind rose A diagram that shows the average percentage of time that the wind blows from different directions, typically on a monthly or annual basis.[1][2] View on Wikipedia Wikipedia Definition A wind rose is a graphic tool used by meteorologists to give a succinct view of how wind speed and direction are typically distributed at a particular location. Historically, wind roses were predecessors of the compass rose, as there was no differentiation between a cardinal direction and the wind which blew from such a direction. Using a polar coordinate system of gridding, the frequency of winds over a long time period are plotted by wind direction, with color bands showing wind ranges. The directions of the rose with the longest spoke show the wind direction with

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

NIST BUILDING SCIENCE SERIES 180 Database-Assisted Design for Wind  

E-Print Network [OSTI]

climatological information on extreme wind speeds and their direction-dependence can be used in conjunction; aerodynamics; extreme winds; database-assisted design; structural dynamics; wind directionality; wind forcesNIST BUILDING SCIENCE SERIES 180 Database-Assisted Design for Wind: Concepts, Software

242

Calibration of the Merrill-G.A.L.C.I.T. wind-tunnel, and a suggestion for a variable cross-section on a small high-speed wind-tunnel.  

E-Print Network [OSTI]

??Speed, power and flow inclination calibration tests run in the Merrill-GALCIT wind-tunnel are described and results presented. A description of the new balance-system is included.… (more)

Schwarzenbach, Jean Christophe

1942-01-01T23:59:59.000Z

243

HEXOS—Humidity Exchange Over the Sea A Program for Research on Water-Vapor and Droplet Fluxes from Sea of Air at Moderate to High Wind Speeds  

Science Journals Connector (OSTI)

HEXOS is an international program for the study of evaporation and spray-droplet flux from sea to air. The program includes measurements in the field at moderate-to-high wind speeds, wind-tunnel studies, instrument development, boundary-layer ...

Kristina B. Katsaros; Stuart D. Smith; Wiebe A. Oost

1987-05-01T23:59:59.000Z

244

Wind Direction Dependence of Atmospheric Boundary Layer Turbulence Parameters in the Urban Roughness Sublayer  

Science Journals Connector (OSTI)

A variety of atmospheric boundary layer parameters are examined as a function of wind direction in both urban and suburban settings in Oklahoma City, Oklahoma, derived from measurements during the Joint Urban 2003 field campaign. Heterogeneous ...

Cheryl Klipp

2007-12-01T23:59:59.000Z

245

Dynamic modeling and direct power control of wind turbine driven DFIG under unbalanced network voltage conditions  

Science Journals Connector (OSTI)

This paper proposes an analysis and a direct power control (DPC) design of a wind turbine driven doubly-fed induction generator (DFIG) under unbalanced network voltage conditions. A DFIG model described in the po...

Jia-bing Hu; Yi-kang He; Lie Xu

2008-12-01T23:59:59.000Z

246

High-speed one-dimensional spatial light modulator for Laser Direct Imaging and other patterning applications  

E-Print Network [OSTI]

High-speed one-dimensional spatial light modulator for Laser Direct Imaging and other patterning developed a one-dimensional high-speed spatial light modulator in cooperation with Micronic Mydata AB of ultraviolet light needs to be combined with high throughput and high precision. Keywords: Laser Direct Imaging

Jonsson, Fredrik

247

On the Heating of the Solar Corona and the Acceleration of the Low-Speed Solar Wind by Acoustic Waves Generated in Corona  

E-Print Network [OSTI]

We investigate possibilities of solar coronal heating by acoustic waves generated not at the photosphere but in the corona, aiming at heating in the mid- to low-latitude corona where the low-speed wind is expected to come from. Acoustic waves of period tau ~ 100s are triggered by chromospheric reconnection, one model of small scale magnetic reconnection events recently proposed by Sturrock. These waves having a finite amplitude eventually form shocks to shape sawtooth waves (N-waves), and directly heat the surrounding corona by dissipation of their wave energy. Outward propagation of the N-waves is treated based on the weak shock theory, so that the heating rate can be evaluated consistently with physical properties of the background coronal plasma without setting a dissipation length in an ad hoc manner. We construct coronal structures from the upper chromosphere to the outside of 1AU for various inputs of the acoustic waves having a range of energy flux of F_{w,0} = (1-20) times 10^5 erg cm^{-2} s^{-1} and a period of tau = 60-300s. The heating by the N-wave dissipation effectively works in the inner corona and we find that the waves of F_{w,0} >= 2 times 10^5 erg cm^{-2} s^{-1} and tau >= 60s could maintain peak coronal temperature, T_{max} > 10^6 K. The model could also reproduce the density profile observed in the streamer region. However, due to its short dissipation length, the location of T_{max} is closer to the surface than the observation, and the resultant flow velocity of the solar wind is lower than the observed profile of the low-speed wind. The cooperations with other heating and acceleration sources with the larger dissipation length are inevitable to reproduce the real solar corona.

Takeru Ken Suzuki

2002-06-14T23:59:59.000Z

248

Wind Resource Assessment Using SODAR at Cluttered Sites William LW Henson MSc*  

E-Print Network [OSTI]

. The UMass ART VT-1 SODAR measures wind speed and direction at multiple heights using the Doppler shift tilted (approximately 15 degrees) from vertical. Three sound beams are required to resolve the wind periods of approximately ten minutes to produce estimates of the mean wind- speed and wind

Massachusetts at Amherst, University of

249

High-Speed Optical Spectroscopy of a Cataclysmic Variable Wind: BZ Camelopardalis  

E-Print Network [OSTI]

BZ Cam is the first cataclysmic variable star with an accretion disk wind evident in its optical spectrum. The wind was found by Thorstensen, who discovered intermittent P Cygni profiles occurring simultaneously in He I 5876 Angstroms and H alpha. We have since obtained spectra with 0.4-Angstroms/pixel dispersion and 60-s time resolution. We find a wind much faster and more rapidly variable than the radiatively accelerated winds of OB stars, Wolf-Rayet stars, or luminous blue variables. Instead of showing blob ejection, the whole wind of BZ Cam appears to turn on and off. We use this to measure the acceleration law of a CV wind for the first time. The velocity increases linearly with time, attaining blue edge velocities near -3000 km/s, and absorption velocities near -1700 km/s, in 6 to 8 min after starting near rest. We also find a subsequent linear deceleration to nearly rest in 30 to 40 min, perhaps an effect of dilution as the wind expands. No periodicity from rotational outflow is obvious. This wind is erratic and incessantly variable, and perhaps bipolar and face-on, but not highly collimated. The P Cygni absorption events trace out sawtooth waves, occurring within 30 to 40 white dwarf radii from the disk. This is the approximate size of the disk, as well as the disk/wind transition region recently postulated by Knigge and Drew. We estimate a distance of 830 +/- 160 pc, and an orbital inclination i such that 12 < i(degrees) < 40.

F. A. Ringwald; T. Naylor

1997-10-02T23:59:59.000Z

250

Semiconductor Laser Lidar Wind Velocity Sensor for Turbine Control  

Science Journals Connector (OSTI)

A dual line-of-sight CW lidar that measures both wind speed and direction is presented. The wind lidar employs a semiconductor laser, which allows for inexpensive remote sensors geared...

Rodrigo, Peter John; Hu, Qi; Pedersen, Christian

251

Wind Resources in Alaska | OpenEI  

Open Energy Info (EERE)

Resources in Alaska Resources in Alaska Dataset Summary Description Wind resource data for Alaska and southeast Alaska, both high resolution wind resource maps and gridded wind parameters. The two high resolution wind maps are comprised of a grid of cells each containing a single value of average wind speed (m/s) at a hub height of 30, 50, 70, and 100 meters and wind power density (W/m^2) at a hub height of 50 meters for a 40,000 square meter area. The additional gridded wind parameter data includes data for points spaced 2 kilometers apart, and include: predicted wind speed frequency distribution as well as speed and energy in 16 directions (the information needed to produce a wind rose image at a given point). Data included here as .kml files (for viewing in Google Earth). GIS shape files available for the gridded wind parameters datasets from AEDI (http://akenergyinventory.org/data.shtml).

252

A fuzzy logic supervisor for active and reactive power control of a variable speed wind energy conversion system associated to a flywheel storage system  

Science Journals Connector (OSTI)

In this paper, we propose a Wind Energy Conversion System (WECS) at variable speed using a Doubly Fed Induction Generator (DFIG) controlled on the rotor side through converters. A Flywheel Energy Storage System (FESS) is connected to the studied wind generator at the DC bus in order to evaluate its capacity to participate to the ancillary services. We study the improvement of the active and reactive power quality produced by the wind generator and its effect on the load voltage regulation connected to the wind generator. For that, a fuzzy logic supervisor is established to control the FESS operation and the DC bus voltage in order to smooth the active power fluctuations due to the random wind speed variations. A control law is also described to smooth the reactive power at the connection node to the grid.

Lilia Jerbi; Lotfi Krichen; Abderrazak Ouali

2009-01-01T23:59:59.000Z

253

Backstepping control of DFIG generators for wide-range variable-speed wind turbines  

Science Journals Connector (OSTI)

In this paper, we have presented a general study of self excited induction generator used in isolated renewable energy conversion source. Tthe behaviour of generated voltage under variable load, rotor speed and excitation capacitance is presented. Also, we have proposed a robust controller suitable in order to control the terminal DC voltage under different speed and AC load conditions for supplied an isolated DC load. The experimental characteristic curve of the generator and simulation result of proposed control scheme are presented.

Badre Bossoufi; Mohammed Karim; Ahmed Lagrioui; Mohammed Taoussi; Mohamed Larbi ElHafyani

2014-01-01T23:59:59.000Z

254

Wind pro?le assessment for wind power purposes.  

E-Print Network [OSTI]

??Preliminary estimation of wind speed at the wind turbine hub height is critically important when planning new wind farms. Wind turbine power output is proportional… (more)

Sointu, Iida

2014-01-01T23:59:59.000Z

255

Sea Surface Roughness and Drag Coefficient as Functions of Neutral Wind Speed  

Science Journals Connector (OSTI)

Near the surface, it is commonly believed that the behavior of the (turbulent) atmospheric flow can be well described by a constant stress layer. In the case of a neutrally stratified surface layer, this leads to the well-known logarithmic wind ...

Hans Hersbach

2011-01-01T23:59:59.000Z

256

MAPping Foehn Winds in the Austrian Alps  

E-Print Network [OSTI]

and the flow above mountain-top level 3. Study the vertical and cross-gap distribution of wind speed-valley horizontal wind speed ("measured") vertical wind speed (calculated) total wind speed & streamlines -20 -10 0 October 1999 ­ TEACO2 calculated 2D winds down-valley horizontal wind speed ("measured") vertical wind

Gohm, Alexander

257

Comparison of new hybrid FEEMD-MLP, FEEMD-ANFIS, Wavelet Packet-MLP and Wavelet Packet-ANFIS for wind speed predictions  

Science Journals Connector (OSTI)

Abstract The technology of wind speed prediction is important to guarantee the safety of wind power utilization. Compared to the single algorithms, the hybrid ones always have better performance in the wind speed predictions. In this paper, three most important decomposing algorithms [Wavelet Decomposition – WD/Wavelet Packet Decomposition – WPD/Empirical Mode Decomposition – EMD] and a latest decomposing algorithm [Fast Ensemble Empirical Mode Decomposition – FEEMD] are all adopted to realize the wind speed high-precision predictions with two representative networks [MLP Neural Network/ANFIS Neural Network]. Based on the hybrid forecasting framework, two new wind speed forecasting methods [FEEMD-MLP and FEEMD-ANFIS] are proposed. Additionally, a series of performance comparison is provided, which includes EMD-MLP, FEEMD-MLP, EDM-ANFIS, FEEMD-ANFIS, WD-MLP, WD-ANFIS, WPD-MLP and WPD-ANFIS. The aim of the study is to investigate the decomposing and forecasting performance of the different hybrid models. Two experimental results show that: (1) Due to the inclusion of the decomposing algorithms, the hybrid ANN algorithms have better performance than their corresponding single ANN algorithms; (2) the proposed new FEEMD-MLP hybrid model has the best performance in the three-step predictions while the WPD-MLP hybrid model has the best performance in the one-step predictions; (3) among the decomposing algorithms, the FEEMD and WPD have better performance than the EMD and WD, respectively; (4) in the forecasting neural networks, the MLP has better performance than the ANFIS; and (5) all of the proposed hybrid algorithms are suitable for the wind speed predictions.

Hui Liu; Hong-qi Tian; Yan-fei Li

2015-01-01T23:59:59.000Z

258

Bias Correction and Bayesian Model Averaging for Ensemble Forecasts of Surface Wind Direction  

E-Print Network [OSTI]

from numerical weather prediction models, which is based on a state-of-the-art circular-processing techniques for forecasts from numerical weather prediction models tend to become ineffective or inapplicableBias Correction and Bayesian Model Averaging for Ensemble Forecasts of Surface Wind Direction Le

Washington at Seattle, University of

259

Simulation of winds as seen by a rotating vertical axis wind turbine blade  

SciTech Connect (OSTI)

The objective of this report is to provide turbulent wind analyses relevant to the design and testing of Vertical Axis Wind Turbines (VAWT). A technique was developed for utilizing high-speed turbulence wind data from a line of seven anemometers at a single level to simulate the wind seen by a rotating VAWT blade. Twelve data cases, representing a range of wind speeds and stability classes, were selected from the large volume of data available from the Clayton, New Mexico, Vertical Plane Array (VPA) project. Simulations were run of the rotationally sampled wind speed relative to the earth, as well as the tangential and radial wind speeds, which are relative to the rotating wind turbine blade. Spectral analysis is used to compare and assess wind simulations from the different wind regimes, as well as from alternate wind measurement techniques. The variance in the wind speed at frequencies at or above the blade rotation rate is computed for all cases, and is used to quantitatively compare the VAWT simulations with Horizontal Axis Wind Turbine (HAWT) simulations. Qualitative comparisons are also made with direct wind measurements from a VAWT blade.

George, R.L.

1984-02-01T23:59:59.000Z

260

Wind Speeds in Two Tornadic Storms and a Tornado, Deduced from Doppler Spectra  

Science Journals Connector (OSTI)

Doppler spectra of a tornado were collected with a radar having a large unambiguous velocity range, ±91 m s?1. Thus for the first time a presentation of nonaliased spectra was possible, showing direct measurement of radial velocities. By fitting ...

Dusan Zrnic; Michael Istok

1980-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Quality Control and Verification of Weather Radar Wind Profiles IWAN HOLLEMAN  

E-Print Network [OSTI]

- tions of the vertical velocity, which is a sum of the vertical wind velocity and the hydrometeor fall. 1986). Profiles of wind speed and direction, hydrometeor fall speed, and divergence have been obtainedQuality Control and Verification of Weather Radar Wind Profiles IWAN HOLLEMAN Royal Netherlands

Stoffelen, Ad

262

Preliminary design and viability consideration of external, shroud-based stators in wind turbine generators  

E-Print Network [OSTI]

Horizontal-axis wind turbine designs often included gearboxes or large direct-drive generators to compensate for the low peripheral speeds of the turbine hub. To take advantage of high blade tip speeds, an alternative ...

Shoemaker-Trejo, Nathaniel (Nathaniel Joseph)

2012-01-01T23:59:59.000Z

263

Estimated global ocean wind power potential from QuikSCAT observations, accounting for turbine characteristics and siting  

E-Print Network [OSTI]

observations, vertical wind speed profile estimation giventhe wind speed profile is reduced, increasing vertical windvertical wind shear with respect to surface layer stability. Wind speeds

Capps, Scott B; Zender, Charles S

2010-01-01T23:59:59.000Z

264

Comparative Assessment of Direct Drive High Temperature Superconducting Generators in Multi-Megawatt Class Wind Turbines  

SciTech Connect (OSTI)

This paper summarizes the work completed under the CRADA between NREL and American Superconductor (AMSC). The CRADA combined NREL and AMSC resources to benchmark high temperature superconducting direct drive (HTSDD) generator technology by integrating the technologies into a conceptual wind turbine design, and comparing the design to geared drive and permanent magnet direct drive (PMDD) wind turbine configurations. Analysis was accomplished by upgrading the NREL Wind Turbine Design Cost and Scaling Model to represent geared and PMDD turbines at machine ratings up to 10 MW and then comparing cost and mass figures of AMSC's HTSDD wind turbine designs to theoretical geared and PMDD turbine designs at 3.1, 6, and 10 MW sizes. Based on the cost and performance data supplied by AMSC, HTSDD technology has good potential to compete successfully as an alternative technology to PMDD and geared technology turbines in the multi megawatt classes. In addition, data suggests the economics of HTSDD turbines improve with increasing size, although several uncertainties remain for all machines in the 6 to 10 MW class.

Maples, B.; Hand, M.; Musial, W.

2010-10-01T23:59:59.000Z

265

Wind power forecast error smoothing within a wind farm  

Science Journals Connector (OSTI)

Smoothing of wind power forecast errors is well-known for large areas. Comparable effects within a wind farm are investigated in this paper. A Neural Network was taken to predict the power output of a wind farm in north-western Germany comprising 17 turbines. A comparison was done between an algorithm that fits mean wind and mean power data of the wind farm and a second algorithm that fits wind and power data individually for each turbine. The evaluation of root mean square errors (RMSE) shows that relative small smoothing effects occur. However, it can be shown for this wind farm that individual calculations have the advantage that only a few turbines are needed to give better results than the use of mean data. Furthermore different results occurred if predicted wind speeds are directly fitted to observed wind power or if predicted wind speeds are first fitted to observed wind speeds and then applied to a power curve. The first approach gives slightly better RMSE values, the bias improves considerably.

Nadja Saleck; Lueder von Bremen

2007-01-01T23:59:59.000Z

266

Peak Power Bi-directional Transfer From High Speed Flywheel to Electrical Regulated Bus Voltage System  

E-Print Network [OSTI]

were performed to determine the energy transfer capabilities of a flywheel coupled high speed permanent magnet synchronous machine through the proposed system's energy storage tank. Results are presented

Szabados, Barna

267

Distributed Wind Energy in Idaho  

SciTech Connect (OSTI)

Project Objective: This project is a research and development program aimed at furthering distributed wind technology. In particular, this project addresses some of the barriers to distributed wind energy utilization in Idaho. Background: At its core, the technological challenge inherent in Wind Energy is the transformation of a highly variable form of energy to one which is compatible with the commercial power grid or another useful application. A major economic barrier to the success of distributed wind technology is the relatively high capital investment (and related long payback periods) associated with wind turbines. This project will carry out fundamental research and technology development to address both the technological and economic barriers. � Active drive train control holds the potential to improve the overall efficiency of a turbine system by allowing variable speed turbine operation while ensuring a tight control of generator shaft speed, thus greatly simplifying power conditioning. � Recent blade aerodynamic advancements have been focused on large, utility-scale wind turbine generators (WTGs) as opposed to smaller WTGs designed for distributed generation. Because of Reynolds Number considerations, blade designs do not scale well. Blades which are aerodynamically optimized for distributed-scale WTGs can potentially reduce the cost of electricity by increasing shaft-torque in a given wind speed. � Grid-connected electric generators typically operate at a fixed speed. If a generator were able to economically operate at multiple speeds, it could potentially convert more of the wind�s energy to electricity, thus reducing the cost of electricity. This research directly supports the stated goal of the Wind and Hydropower Technologies Program for Distributed Wind Energy Technology: By 2007, reduce the cost of electricity from distributed wind systems to 10 to 15 cents/kWh in Class 3 wind resources, the same level that is currently achievable in Class 5 winds.

Gardner, John; Ferguson, James; Ahmed-Zaid, Said; Johnson, Kathryn; Haynes, Todd; Bennett, Keith

2009-01-31T23:59:59.000Z

268

Review of Wind Energy Forecasting Methods for Modeling Ramping Events  

SciTech Connect (OSTI)

Tall onshore wind turbines, with hub heights between 80 m and 100 m, can extract large amounts of energy from the atmosphere since they generally encounter higher wind speeds, but they face challenges given the complexity of boundary layer flows. This complexity of the lowest layers of the atmosphere, where wind turbines reside, has made conventional modeling efforts less than ideal. To meet the nation's goal of increasing wind power into the U.S. electrical grid, the accuracy of wind power forecasts must be improved. In this report, the Lawrence Livermore National Laboratory, in collaboration with the University of Colorado at Boulder, University of California at Berkeley, and Colorado School of Mines, evaluates innovative approaches to forecasting sudden changes in wind speed or 'ramping events' at an onshore, multimegawatt wind farm. The forecast simulations are compared to observations of wind speed and direction from tall meteorological towers and a remote-sensing Sound Detection and Ranging (SODAR) instrument. Ramping events, i.e., sudden increases or decreases in wind speed and hence, power generated by a turbine, are especially problematic for wind farm operators. Sudden changes in wind speed or direction can lead to large power generation differences across a wind farm and are very difficult to predict with current forecasting tools. Here, we quantify the ability of three models, mesoscale WRF, WRF-LES, and PF.WRF, which vary in sophistication and required user expertise, to predict three ramping events at a North American wind farm.

Wharton, S; Lundquist, J K; Marjanovic, N; Williams, J L; Rhodes, M; Chow, T K; Maxwell, R

2011-03-28T23:59:59.000Z

269

Reactive capability limits of wind farms  

Science Journals Connector (OSTI)

Wind Energy Conversion Systems (WECS) technology can be classified into two main types: fixed speed and variable speed. Fixed speed WECS use an induction generator connected directly to the grid while variable speed WECS use a power converter to connect the generator to the grid. Fixed speed WECS require shunt capacitors for reactive power compensation, while variable speed WECS have reactive power capability. Under the Spanish grid code, wind farms have to operate in a range of power factor values. This paper determines the reactive power capability of wind farms equipped with both fixed and variable speed WECS. The reactive power capability can be represented as a reactive capability curve. In this paper, the reactive capability curve is used to calculate the additional reactive power compensation needed to meet the requirements of the Spanish grid code.

Alberto Rios Villacorta; Santiago Arnaltes Gomez; Jose Luis Rodriguez-Amenedo

2005-01-01T23:59:59.000Z

270

Wind variability in the northwestern part of the Black Sea from the offshore fixed platform observation data  

Science Journals Connector (OSTI)

The statistically ensured estimates of characteristics of temporal variability of wind speed and wind direction are obtained on the basis of ... observations carried out in 1996–2001 at the offshore fixed platfor...

A. V. Garmashov; A. B. Polonskii

2011-12-01T23:59:59.000Z

271

Investigation of 4-ASK modulation with digital filtering to increase 20 times of direct modulation speed of white-light LED visible light communication system  

Science Journals Connector (OSTI)

In this demonstration, we propose and experimentally investigate the quaternary-amplitude-shift-keying (4-ASK) modulation with digital filtering to enhance the direct modulation speed...

Yeh, C H; Liu, Y F; Chow, C W; Liu, Y; Huang, P Y; Tsang, H K

2012-01-01T23:59:59.000Z

272

A framework for estimating stratospheric wind speeds from unknown sources and application to the 2010 December 25 bolide  

Science Journals Connector (OSTI)

......provide group velocities (referred to...the Horizontal Wind Model (HWM)/Mass Spectrometer...measured trace velocity and celerity...measured trace velocity of the signal...Green 2012). Wind and temperature...Figure 1. Map of the Utah......

Stephen J. Arrowsmith; Omar Marcillo; Douglas P. Drob

2013-01-01T23:59:59.000Z

273

SODAR Wind Resource Measurement Results at Falmouth, MA Prepared for  

E-Print Network [OSTI]

of Massachusetts at Amherst. The data were collected to estimate the wind resource for possible wind turbines to well over 100 m. The operation of a SODAR and the SODAR data are described in this report. SODAR Technology The UMass ART VT-1 SODAR measures wind speed and direction at multiple heights using an acoustic

Massachusetts at Amherst, University of

274

Low Wind Speed Technology Phase I: Evaluation of Design and Construction Approaches for Economical Hybrid Steel/Concrete Wind Turbine Towers; BERGER/ABAM Engineers Inc.  

SciTech Connect (OSTI)

This fact sheet describes a subcontract with BERGER/ABAM Engineers Inc. to study the economic feasibility of concrete and hybrid concrete/steel wind turbine towers.

Not Available

2006-03-01T23:59:59.000Z

275

The Inside of a Wind Turbine | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

The Inside of a Wind Turbine The Inside of a Wind Turbine The Inside of a Wind Turbine 1 of 17 Tower: 2 of 17 Tower: Made from tubular steel (shown here), concrete, or steel lattice. Supports the structure of the turbine. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity. Generator: 3 of 17 Generator: Produces 60-cycle AC electricity; it is usually an off-the-shelf induction generator. High-speed shaft: 4 of 17 High-speed shaft: Drives the generator. Nacelle: 5 of 17 Nacelle: Sits atop the tower and contains the gear box, low- and high-speed shafts, generator, controller, and brake. Some nacelles are large enough for a helicopter to land on. Wind vane: 6 of 17 Wind vane: Measures wind direction and communicates with the yaw drive to orient the

276

The effect of ocean waves on offshore wind turbines  

Science Journals Connector (OSTI)

The Ocean has a varying surface roughness where the roughness length is determined by the characteristics of the waves. In this paper, a method is established where the roughness length of the ocean is calculated from the wind speed and the fetch length. The fetch length depends on the wind direction and a case study is performed for a wind turbine exposed to wind blowing in two opposite directions: from the shore and the sea. For each case, the vertical wind speed distribution is calculated in order to study the influence that the direction of the wind has on the annual energy production. The potential for using a site-specific offshore turbine design, dependent on the prevailing wind direction, is also explored.

T. Thorsen; H. Naeser

2002-01-01T23:59:59.000Z

277

Employing two novel mechanical fault ride through controllers for keeping stability of fixed speed wind generation systems hosted by standalone micro-grid  

Science Journals Connector (OSTI)

Abstract This paper proposes and designs two novels Fault Ride Through (FRT) controllers for maintaining Fixed Speed Wind Generation system (FSWGs) stability during fault events. The first technique has been implemented by increasing the wind turbine blade pitch angle with maximum possible rate to reduce the mechanical extracted wind power and consequently suppress wind generation system acceleration. The second FRT technique has been verified by adapting gear ratio of wind generation system to run far from optimum maximum power point and help FRT process. Effectiveness of the two proposed FRT techniques has been proven by accurate simulation of the most severe disturbance conditions. Also, Results indicated that second technique gives faster response than the first one. Without employing any FRT technique, \\{FSWGs\\} cannot keep its stability and the standalone Micro-Grid (MG) transfers to the blackout mode. Implementation the two FRT techniques requires no additional hardware. Only, control algorithms need little modification to deal with fault event and help FRT process. This fact makes the two proposed FRT techniques are simple, practical and highly economical attractive.

Rashad M. Kamel

2014-01-01T23:59:59.000Z

278

Direct measurement of instantaneous source speed for a HDR brachytherapy unit using an optical fiber based detector  

SciTech Connect (OSTI)

Purpose: Several attempts to determine the transit time of a high dose rate (HDR) brachytherapy unit have been reported in the literature with controversial results. The determination of the source speed is necessary to accurately calculate the transient dose in brachytherapy treatments. In these studies, only the average speed of the source was measured as a parameter for transit dose calculation, which does not account for the realistic movement of the source, and is therefore inaccurate for numerical simulations. The purpose of this work is to report the implementation and technical design of an optical fiber based detector to directly measure the instantaneous speed profile of a {sup 192}Ir source in a Nucletron HDR brachytherapy unit. Methods: To accomplish this task, we have developed a setup that uses the Cerenkov light induced in optical fibers as a detection signal for the radiation source moving inside the HDR catheter. As the {sup 192}Ir source travels between two optical fibers with known distance, the threshold of the induced signals are used to extract the transit time and thus the velocity. The high resolution of the detector enables the measurement of the transit time at short separation distance of the fibers, providing the instantaneous speed. Results: Accurate and high resolution speed profiles of the {sup 192}Ir radiation source traveling from the safe to the end of the catheter and between dwell positions are presented. The maximum and minimum velocities of the source were found to be 52.0{+-}1.0 and 17.3{+-}1.2 cm/s. The authors demonstrate that the radiation source follows a uniformly accelerated linear motion with acceleration of |a|=113 cm/s{sup 2}. In addition, the authors compare the average speed measured using the optical fiber detector to those obtained in the literature, showing deviation up to 265%. Conclusions: To the best of the authors' knowledge, the authors directly measured for the first time the instantaneous speed profile of a radiation source in a HDR brachytherapy unit traveling from the unit safe to the end of the catheter and between interdwell distances. The method is feasible and accurate to implement on quality assurance tests and provides a unique database for efficient computational simulations of the transient dose.

Minamisawa, R. A.; Rubo, R. A.; Seraide, R. M.; Rocha, J. R. O.; Almeida, A. [Department of Physics and Mathematics, FFCLRP, University of Sao Paulo, 14040-901, Ribeirao Preto-SP (Brazil); INRAD, Medical School - University of Sao Paulo, Clinical Hospital (HCUSP), 05403-001, Sao Paulo-SP (Brazil); CAISM Radiotherapy Service, CEB, State University of Campinas, 13083-881, Campinas-SP (Brazil); Department of Physics and Mathematics, FFCLRP, University of Sao Paulo, 14040-901, Ribeirao Preto-SP (Brazil)

2010-10-15T23:59:59.000Z

279

Connecting speeds, directions and arrival times of 22 coronal mass ejections from the Sun to 1 AU  

E-Print Network [OSTI]

Forecasting the in situ properties of coronal mass ejections (CMEs) from remote images is expected to strongly enhance predictions of space weather, and is of general interest for studying the interaction of CMEs with planetary environments. We study the feasibility of using a single heliospheric imager (HI) instrument, imaging the solar wind density from the Sun to 1 AU, for connecting remote images to in situ observations of CMEs. We compare the predictions of speed and arrival time for 22 CMEs (in 2008-2012) to the corresponding interplanetary coronal mass ejection (ICME) parameters at in situ observatories (STEREO PLASTIC/IMPACT, Wind SWE/MFI). The list consists of front- and backsided, slow and fast CMEs (up to $2700 \\: km \\: s^{-1}$). We track the CMEs to $34.9 \\pm 7.1$ degrees elongation from the Sun with J-maps constructed using the SATPLOT tool, resulting in prediction lead times of $-26.4 \\pm 15.3$ hours. The geometrical models we use assume different CME front shapes (Fixed-$\\Phi$, Harmonic Mean, S...

Möstl, C; Hall, J R; Liewer, P C; De Jong, E M; Colaninno, R C; Veronig, A M; Rollett, T; Temmer, M; Peinhart, V; Davies, J A; Lugaz, N; Liu, Y D; Farrugia, C J; Luhmann, J G; Vršnak, B; Harrison, R A; Galvin, A B

2014-01-01T23:59:59.000Z

280

Analysis of Alongwind Tall Building Response to Transient Nonstationary Winds  

E-Print Network [OSTI]

where the mean wind speed is characterized by a time-invariant vertical profile and a single time of time varying mean wind speed, mean wind speed vertical profile, and spatial correlation of wind flows in terms of its unique mean wind speed vertical profile, rapid time varying mean wind speed

Chen, Xinzhong

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Wind Tunnel Evaluation of PAM II Pressure Ports  

Science Journals Connector (OSTI)

The Portable Automated Mesonet II (PAM II) is a network of automated remote weather stations developed by the National Center for Atmospheric Research (NCAR) for measuring wind speed and direction, atmospheric pressure, temperature, humidity, and ...

Fikri Adnan Akyüz; Henry Liu; Tom Horst

1991-06-01T23:59:59.000Z

282

10MW Class Direct Drive HTS Wind Turbine: Cooperative Research and Development Final Report, CRADA Number CRD-08-00312  

SciTech Connect (OSTI)

This paper summarizes the work completed under the CRADA between NREL and American Superconductor (AMSC). The CRADA combined NREL and AMSC resources to benchmark high temperature superconducting direct drive (HTSDD) generator technology by integrating the technologies into a conceptual wind turbine design, and comparing the design to geared drive and permanent magnet direct drive (PMDD) wind turbine configurations. Analysis was accomplished by upgrading the NREL Wind Turbine Design Cost and Scaling Model to represent geared and PMDD turbines at machine ratings up to 10 MW and then comparing cost and mass figures of AMSC's HTSDD wind turbine designs to theoretical geared and PMDD turbine designs at 3.1, 6, and 10 MW sizes.

Musial, W.

2011-05-01T23:59:59.000Z

283

Space-time forecasting and evaluation of wind speed with statistical tests for comparing accuracy of spatial predictions  

E-Print Network [OSTI]

). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 11 Comparing the predictive distributions for the models when the TDD model produces the best forecast (top panel) and when the BST model produces the best forecast (bottom panel). The small vertical line on the x-axis of each plot represents... of wind to benefit humans is not a new concept. Historically, wind- mills have been used to pump water from wells or to grind grain for centuries. But fast- forwarding into the 21st century, ?windmills? are being used to generate electricity. Wind turbines...

Hering, Amanda S.

2010-10-12T23:59:59.000Z

284

An Efficient Wide-Speed Direct Torque Control Based on Fuzzy Logic Technique.  

E-Print Network [OSTI]

??Conventional Direct Torque Control (CDTC) system faces the problems of high flux and torque ripples, and has difficulty in improving the performance of dynamic torque… (more)

Zhao, Jibo

2012-01-01T23:59:59.000Z

285

A Climatological Study of Boundary Layer Wind Speed Using a Meso-?-Scale Higher-Order Closure Model  

Science Journals Connector (OSTI)

A mesoscale higher-order closure atmospheric boundary layer model has been used to get more detailed information than is possible from observations regarding horizontal and vertical variations of the wind in an area in southeastern Sweden. To ...

Hans Bergström

1996-08-01T23:59:59.000Z

286

Aeroacoustic Testing of Wind Turbine Airfoils: February 20, 2004 - February 19, 2008  

SciTech Connect (OSTI)

The U.S. Department of Energy (DOE), working through its National Renewable Energy Laboratory (NREL), is engaged in a comprehensive research effort to improve the understanding of wind turbine aeroacoustics. The motivation for this effort is the desire to exploit the large expanse of low wind speed sites that tend to be close to U.S. load centers. Quiet wind turbines are an inducement to widespread deployment, so the goal of NREL's aeroacoustic research is to develop tools that the U.S. wind industry can use in developing and deploying highly efficient, quiet wind turbines at low wind speed sites. NREL's National Wind Technology Center (NWTC) is implementing a multifaceted approach that includes wind tunnel tests, field tests, and theoretical analyses in direct support of low wind speed turbine development by its industry partners. NWTC researchers are working hand in hand with engineers in industry to ensure that research findings are available to support ongoing design decisions.

Devenport, W.; Burdisso, R. A.; Camargo, H.; Crede, E.; Remillieux, M.; Rasnick, M.; Van Seeters, P.

2010-05-01T23:59:59.000Z

287

Hydrodynamics and drive-train dynamics of a direct-drive floating wind turbine   

E-Print Network [OSTI]

Floating wind turbines (FWTs) are considered a new lease of opportunity for sustaining growth from offshore wind energy. In recent years, several new concepts have emerged, with only a few making it to demonstration or ...

Sethuraman, Latha

2014-06-30T23:59:59.000Z

288

Guide to Using the WIND Toolkit Validation Code  

SciTech Connect (OSTI)

In response to the U.S. Department of Energy's goal of using 20% wind energy by 2030, the Wind Integration National Dataset (WIND) Toolkit was created to provide information on wind speed, wind direction, temperature, surface air pressure, and air density on more than 126,000 locations across the United States from 2007 to 2013. The numerical weather prediction model output, gridded at 2-km and at a 5-minute resolution, was further converted to detail the wind power production time series of existing and potential wind facility sites. For users of the dataset it is important that the information presented in the WIND Toolkit is accurate and that errors are known, as then corrective steps can be taken. Therefore, we provide validation code written in R that will be made public to provide users with tools to validate data of their own locations. Validation is based on statistical analyses of wind speed, using error metrics such as bias, root-mean-square error, centered root-mean-square error, mean absolute error, and percent error. Plots of diurnal cycles, annual cycles, wind roses, histograms of wind speed, and quantile-quantile plots are created to visualize how well observational data compares to model data. Ideally, validation will confirm beneficial locations to utilize wind energy and encourage regional wind integration studies using the WIND Toolkit.

Lieberman-Cribbin, W.; Draxl, C.; Clifton, A.

2014-12-01T23:59:59.000Z

289

Modelling and control of a variable speed wind turbine driving doubly fed induction generator using three-level PWM converter  

Science Journals Connector (OSTI)

The aim of this researcher is to develop a complete wind central model driven doubly fed induction generator (DFIG) which feeds an AC power grid. For that, two-pulse width modulated (PWM) voltage converters are connected back to back between the rotor terminals of DFIG and the utility grid via a common DC link, in there, our contribution will appear in the utilisation of three levels voltage inverters in order to ameliorate the energy quality. The simulation was carried out on a 2 MW wind-turbine driven DFIG system and the developed unified model validity and the proposed control strategies feasibility are all confirmed by the simulated results.

Fairouz Kendouli; Khoudir Abed; Khalil Nabti; Hocine Benalla

2012-01-01T23:59:59.000Z

290

The InterHourly-Variability (IHV) Index of Geomagnetic Activity and its Use in Deriving the Long-term Variation of Solar Wind Speed  

E-Print Network [OSTI]

We describe the derivation of the InterHourly Variability (IHV) index of geomagnetic activity. The IHV-index for a geomagnetic element is mechanically derived from hourly values as the sum of the unsigned differences between adjacent hours over a seven-hour interval centered on local midnight. The index is derived separately for stations in both hemispheres within six longitude sectors using only local night hours. It is intended as a long-term index. Available data allows derivation of the index back well into the 19th century. On a time scale of a 27-day Bartels rotation, IHV averages for stations with corrected geomagnetic latitude less than 55 degrees are strongly correlated with midlatitude range indices. Assuming a constant calibration of the aa-index we find that observed yearly values of aa before the year 1957 are 2.9 nT too small compared to values calculated from IHV using the regression constants based on 1980-2004. We interpret this discrepancy as an indication that the calibration of the aa index is in error before 1957. There is no such problem with the ap index. Rotation averages of IHV are also strongly correlated with solar wind parameters (BV^2). On a time scale of a year combining the IHV-index and the recently-developed Inter-Diurnal Variability (IDV) index (giving B) allows determination of solar wind speed, V, from 1890-present. Over the ~120-year series, the yearly mean solar wind speed varied from a low of 303 km/s in 1902 to a high value of 545 km/s in 2003. The calculated yearly values of the product BV using B and V separately derived from IDV and IHV agree quantitatively with (completely independent) BV derived from the amplitude of the diurnal variation of the H component in the polar caps since 1926 and sporadically beyond.

Leif Svalgaard; Edward W. Cliver

2007-06-07T23:59:59.000Z

291

Potential wind power generation in South Egypt  

Science Journals Connector (OSTI)

Egypt is one of the developing countries. The production of electricity in Egypt is basically on petroleum, natural gas, hydro-power and wind energy. The objective of this work to prove the availability of sufficient wind potential in the wide area of deep south Egypt for the operation of wind turbines there. Nevertheless, it gives in general an approximate profile which is useful to the wind parks design for this area. The data used in the calculation are published and analyzed for the first time. The diagrams of the measured wind data for three meteorological stations over a period of two years (wind speed, frequency, direction), wind shear coefficient, the mean monthly and annual wind speed profile for every location are presented. Monthly Weibull parameters, standard deviation and coefficient of variation have been statistically discussed. A comparison of the rose diagrams shows that the wind speed is more persistent and blow over this region of Egypt in two main sectors N and NNW with long duration of frequencies from 67% to 87% over the year with an average wind speed in the range 6.8–7.9 m/s at the three stations. Evaluation of monthly wind energy density at 10 m height by two different methods was carried out. And the final diagram for every site shows no significant difference between them. The annual natural wind energies at 70 m A.G.L. lie between 333 and 377 W/m2 for Dakhla South and Kharga stations, respectively, which is similar to the inland wind potential of Vindeby (Denmark) and some European countries. These results indicate that Kharga and Dakhla South locations are new explored sites for future wind power generation projects.

Ahmed Shata Ahmed

2012-01-01T23:59:59.000Z

292

Optimization of direct drive induction motors for electric ship propulsion with high speed propellers  

Science Journals Connector (OSTI)

Direct drive electric ship propulsion can offer increased flexibility and reduced overall fuel consumption compared to geared mechanical systems [Davis 1987, Doerry 2007]. As a well-established technology, induction motors are a dependable and economical ... Keywords: AC motors, induction motor drives, induction motors, thermal analysis

S. C. Englebretson; J. L. Kirtley, Jr; C. Chryssostomidis

2009-07-01T23:59:59.000Z

293

Assembling spatially explicit landscape models of pollen and spore dispersal by wind for risk assessment  

Science Journals Connector (OSTI)

...the direction of the wind, a simplified physical...rise to an inverse power-law with an exponent 3/2 along the wind. Using a more detailed...particles, such as most plant seeds, with a terminal...with mean vertical wind speeds. This model...cut-off and within this power-law behaviour with...

2006-01-01T23:59:59.000Z

294

Commuting fruit bats beneficially modulate their flight in relation to wind  

Science Journals Connector (OSTI)

...depicted by colour, according to wind direction (x-axis) and wind speed (y-axis). (a) Results...out under permission from the Wildlife Division of the Forestry Commission...12219 ) 3 Alerstam, T . 1979 Wind as selective agent in bird migration...

2014-01-01T23:59:59.000Z

295

ARM - Measurement - Horizontal wind  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

govMeasurementsHorizontal wind govMeasurementsHorizontal wind ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Horizontal wind The horizontal wind in terms of either speed and direction, or the zonal (u) and meridional (v) components. Categories Atmospheric State Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments SONDE : Balloon-Borne Sounding System CO2FLX : Carbon Dioxide Flux Measurement Systems ECOR : Eddy Correlation Flux Measurement System DISDROMETER : Impact Disdrometer

296

Study of the Reliability Enhancement of Wind Turbines Employing Direct-drive Technology.  

E-Print Network [OSTI]

??In traditional wind turbines employing gearboxes, the blades spin a shaft that is connected through a gearbox to the generator. The multiple wheels and bearings… (more)

Sara George, Reeba

2012-01-01T23:59:59.000Z

297

A new design of wind tower for passive ventilation in buildings to reduce energy consumption in windy regions  

Science Journals Connector (OSTI)

Abstract In today’s world, the significance of energy and energy conservation is a common knowledge. Wind towers can save the electrical energy used to provide thermal comfort during the warm months of the year, especially during the peak hours. In this paper, we propose a new design for wind towers. The proposed wind towers are installed on top of the buildings, in the direction of the maximum wind speed in the region. If the desired wind speed is accessible in several directions, additional wind towers can be installed in several positions. The proposed wind tower can also rotate and set itself in the direction of the maximum wind speed. In the regions where the wind speed is low, to improve the efficiency of the system a solar chimney or a one-sided wind tower can be installed in another part of the building in the opposite direction. Using transparent materials in the manufacturing of the proposed wind towers improves the use of natural light inside the building. The major advantage of wind towers is that they are passive systems requiring no energy for operation. Also, wind towers reduce electrical energy consumption and environmental pollution.

A.R. Dehghani-sanij; M. Soltani; K. Raahemifar

2015-01-01T23:59:59.000Z

298

Technology Improvement Opportunities for Low Wind Speed Turbines and Implications for Cost of Energy Reduction: July 9, 2005 - July 8, 2006  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Technology Improvement Technology Improvement Opportunities for Low Wind Speed Turbines and Implications for Cost of Energy Reduction July 9, 2005 - July 8, 2006 J. Cohen and T. Schweizer Princeton Energy Resources International (PERI) Rockville, Maryland A. Laxson, S. Butterfield, S. Schreck, and L. Fingersh National Renewable Energy Laboratory Golden, Colorado P. Veers and T. Ashwill Sandia National Laboratories Albuquerque, New Mexico Technical Report NREL/TP-500-41036 February 2008 NREL is operated by Midwest Research Institute â—Ź Battelle Contract No. DE-AC36-99-GO10337 National Renewable Energy Laboratory 1617 Cole Boulevard, Golden, Colorado 80401-3393 303-275-3000 * www.nrel.gov Operated for the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy

299

WP2 IEA Wind Task 26:The Past and Future Cost of Wind Energy  

E-Print Network [OSTI]

Energy Efficiency and Renewable Energy, Wind and HydropowerSpeed Sites. ” European Wind Energy Association. Marseille,Innovation and the price of wind energy in the US. ” Energy

Lantz, Eric

2014-01-01T23:59:59.000Z

300

WP2 IEA Wind Task 26:The Past and Future Cost of Wind Energy  

E-Print Network [OSTI]

Speed Sites. ” European Wind Energy Association. Marseille,Innovation and the price of wind energy in the US. ” EnergyThe Economics of Wind Energy. ” Renewable and Sustainable

Lantz, Eric

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

An Analysis of Wintertime Winds in Washington, D.C.  

SciTech Connect (OSTI)

This report consists of a description of the wintertime climatology of wind speed and wind direction around the National Mall in Washington, D.C. Meteorological data for this study were collected at Ronald Reagan Washington National Airport (Reagan National), Dulles International Airport (Dulles), and a set of surface meteorological stations that are located on a number of building tops around the National Mall. A five-year wintertime climatology of wind speed and wind direction measured at Reagan National and Dulles are presented. A more detailed analysis was completed for the period December 2003 through February 2004 using data gathered from stations located around the National Mall, Reagan National, and Dulles. Key findings of our study include the following: * There are systematic differences between the wind speed and wind direction observed at Reagan National and the wind speed and wind direction measured by building top weather stations located in the National Mall. Although Dulles is located much further from the National Mall than Reagan National, there is better agreement between the wind speed and wind direction measured at Dulles and the weather stations in the National Mall. * When the winds are light (less than 3 ms-1 or 7 mph), there are significant differences in the wind directions reported at the various weather stations within the Mall. * Although the mean characteristics of the wind are similar at the various locations, significant, short-term differences are found when the time series are compared. These differences have important implications for the dispersion of airborne contaminants. In support of wintertime special events in the area of the National Mall, we recommend placing four additional meteorological instruments: three additional surface stations, one on the east bank of the Potomac River, one south of the Reflecting Pool (to better define the flow within the Mall), and a surface station near the Herbert C. Hoover Building; and wind-profiling instrument located along the southern edge of the National Mall to give measurements of the wind speed and direction as a function of height.

Berg, Larry K.; Allwine, K Jerry

2006-06-20T23:59:59.000Z

302

Offshore Wind Potential Tables  

Wind Powering America (EERE)

Offshore wind resource by state and wind speed interval within 50 nm of shore. Wind Speed at 90 m (ms) 7.0 - 7.5 7.5 - 8.0 8.0 - 8.5 8.5 - 9.0 9.0 - 9.5 9.5 - 10.0 >10.0 Total...

303

Towers for Offshore Wind Turbines  

Science Journals Connector (OSTI)

Increasing energy demand coupled with pollution free production of energy has found a viable solution in wind energy. Land based windmills have been utilized for power generation for more than two thousand years. In modern times wind generated power has become popular in many countries. Offshore wind turbines are being used in a number of countries to tap the energy from wind over the oceans and convert to electric energy. The advantages of offshore wind turbines as compared to land are that offshore winds flow at higher speed than onshore winds and the more available space. In some land based settings for better efficiency turbines are separated as much as 10 rotor diameters from each other. In offshore applications where only two wind directions are likely to predominate the distances between the turbines arranged in a line can be shortened to as little as two or four rotor diameters. Today more than a dozen offshore European wind facilities with turbine ratings of 450 kw to 3.6 MW exist offshore in very shallow waters of 5 to 12 m. Compared to onshore wind turbines offshore wind turbines are bigger and the tower height in offshore are in the range of 60 to 80 m. The water depths in oceans where offshore turbines can be located are within 30 m. However as the distance from land increases the costs of building and maintaining the turbines and transmitting the power back to shore also increase sharply. The objective of this paper is to review the parameters of design for the maximum efficiency of offshore wind turbines and to develop types offshore towers to support the wind turbines. The methodology of design of offshore towers to support the wind turbine would be given and the environmental loads for the design of the towers would be calculated for specific cases. The marine corrosion on the towers and the methods to control the corrosion also would be briefly presented. As the wind speeds tend to increase with distance from the shore turbines build father offshore will be able to capture more wind energy. Currently two types of towers are considered. Cylindrical tubular structures and truss type structures. But truss type structures have less weight and flexibility in design. The construction of the offshore towers to harness the wind energy is also presented. The results will include the calculation of wind and wave forces on the tower and the design details for the tower.

V. J. Kurian; S. P. Narayanan; C. Ganapathy

2010-01-01T23:59:59.000Z

304

A study of wind variation with time in the vicinity of the jet stream  

E-Print Network [OSTI]

to remember when using any meteorological data, particularly wind reports, is that, even if extremely large amounts of wind data were available at all levels ower the entire globe, average values of wind flow obtained by statistical analysis would... be of little value for planniag operations or design problems, 'Ihe deviations from the average values of wind direction and speed which occur at any location over a short interval of time are very large, The extremes and the time variations...

Bandow, Donald Elmer

2012-06-07T23:59:59.000Z

305

Investigation of wind characteristics and wind energy potential at Ras Ghareb, Egypt  

Science Journals Connector (OSTI)

To study the structure of a coastal location «Ras Ghareb» on the Red Sea in Egypt, a measurement station with mast of 24.5 m has been established in a built-up area, near the seashore. First, a statistical analysis of the measured data over the period 2000–2005 was performed, including calculation of the wind speed power law index which was found to be 0.18 for Ras Ghareb area. Then, wind speed data was expressed at the height of (usually 10 m) which makes it directly related to the objective of those people working in the renewable energy sector. Therefore, the mean wind speeds, availability of data, seasonal variation and the distribution by the wind direction were studied to ascertain its potential for wind energy development. The annual wind speed over this site varies from 8.3 to 9.8 m/s at 10 and 24.5 m heights, respectively. Most of the time 73% the mean wind speed in the ranges 5–10 and 10–17 m/s at 10 m. Also, higher winds of the order 10 m/s and more observed during summer months. The main wind direction is north–northwest sector (330°) for about 51% of the times during the year that makes it unique for installation of wind parks. Second, numerical estimations to determine the seasonal power law coefficient and Weibull parameters at different heights from 10 to 100 m were carried out. Finally, Rayleigh distribution and our method stated in Ref. [3] were adopted for defining the monthly wind power available at 10 m height for this region. It is emphasized that Rayleigh model is not appropriate and our method is more efficient for Ras Ghareb area. Where the expected mean of wind power density was found to quite high 360 W/m2 per year at 10 m hub height, which makes this station likely candidates for wind power utilization. It is appear from our analysis that Ras Ghareb region can be explored for generating the electricity. Where the monthly and annual pattern of wind speed matches the electricity load pattern of the location.

Ahmed Shata Ahmed

2011-01-01T23:59:59.000Z

306

Ris-PhD-Report Sensing the wind profile  

E-Print Network [OSTI]

for wind speed measurements performed at either sites. The wind speed measurements are averaged for several to scale the wind speed with the surface friction velocity, whereas at Horns Rev a new scaling is added deviate from the logarithmic wind prole, but agree better with the wind speed measurements. The length

307

Simulation of Short-term Wind Speed Forecast Errors using a Multi-variate ARMA(1,1) Time-series Model.  

E-Print Network [OSTI]

?? The short-term (1 to 48 hours) predictability of wind power production from wind power plants in a power system is critical to the value… (more)

Boone, Andrew

2005-01-01T23:59:59.000Z

308

ABO Wind AG | Open Energy Information  

Open Energy Info (EERE)

AG Place: Hessen, Germany Zip: 65193 Sector: Bioenergy, Wind energy Product: German developer of wind and bioenergy generation assets. ABO Wind has no direct holding in any wind...

309

Method and apparatus for digitally based high speed x-ray spectrometer for direct coupled use with continuous discharge preamplifiers  

DOE Patents [OSTI]

A high speed, digitally based, signal processing system which accepts directly coupled input data from a detector with a continuous discharge type preamplifier and produces a spectral analysis of the x-rays illuminating the detector. The system's principal elements are an analog signal conditioning section, a combinatorial logic section which implements digital triangular filtering and pileup inspection, and a microprocessor which accepts values captured by the logic section and uses them to compute x-ray energy values. Operating without pole-zero correction, the system achieves high resolution by capturing, in conjunction with each peak value from the digital filter, an associated value of the unfiltered signal, and using this latter signal to correct the former for errors which arise from its local slope terms. This correction greatly reduces both energy resolution degradation and peak centroid shifting in the output spectrum as a function of input count rate. When the noise of this correction is excessive, a modification allows two filtered averages of the signal to be captured and a corrected peak amplitude computed therefrom.

Warburton, William K. (1300 Mills St., Menlo Park, CA 94025)

1998-01-01T23:59:59.000Z

310

Method and apparatus for digitally based high speed x-ray spectrometer for direct coupled use with continuous discharge preamplifiers  

DOE Patents [OSTI]

A high speed, digitally based, signal processing system is disclosed which accepts directly coupled input data from a detector with a continuous discharge type preamplifier and produces a spectral analysis of the x-rays illuminating the detector. The system`s principal elements are an analog signal conditioning section, a combinatorial logic section which implements digital triangular filtering and pileup inspection, and a microprocessor which accepts values captured by the logic section and uses them to compute x-ray energy values. Operating without pole-zero correction, the system achieves high resolution by capturing, in conjunction with each peak value from the digital filter, an associated value of the unfiltered signal, and using this latter signal to correct the former for errors which arise from its local slope terms. This correction greatly reduces both energy resolution degradation and peak centroid shifting in the output spectrum as a function of input count rate. When the noise of this correction is excessive, a modification allows two filtered averages of the signal to be captured and a corrected peak amplitude computed therefrom. 14 figs.

Warburton, W.K.

1998-06-30T23:59:59.000Z

311

An Improved Method for Estimating the Wind Power Density Distribution Function  

Science Journals Connector (OSTI)

The wind power density (WPD) distribution curve is essential for wind power assessment and wind turbine engineering. The usual practice of estimating this curve from wind speed data is to first estimate the wind speed probability density function ...

Mark L. Morrissey; Werner E. Cook; J. Scott Greene

2010-07-01T23:59:59.000Z

312

New England Wind Forum: Wind Power Economics  

Wind Powering America (EERE)

State Activities Projects in New England Building Wind Energy in New England Wind Resource Wind Power Technology Economics Cost Components Determining Factors Influencing Wind Economics in New England How does wind compare to the cost of other electricity options? Markets Siting Policy Technical Challenges Issues Small Wind Large Wind Newsletter Perspectives Events Quick Links to States CT MA ME NH RI VT Bookmark and Share Wind Power Economics Long-Term Cost Trends Since the first major installations of commercial-scale wind turbines in the 1980s, the cost of energy from wind power projects has decreased substantially due to larger turbine generators, towers, and rotor lengths; scale economies associated with larger projects; improvements in manufacturing efficiency, and technological advances in turbine generator and blade design. These technological advances have allowed for higher generating capacities per turbine and more efficient capture of wind, especially at lower wind speeds.

313

Direct Simulations of Wind-Driven Breaking Ocean Waves with Data Assimilation  

E-Print Network [OSTI]

A formulation is developed to assimilate ocean-wave data into the Numerical Flow Analysis (NFA) code. NFA is a Cartesian-based implicit Large-Eddy Simulation (LES) code with Volume of Fluid (VOF) interface capturing. The sequential assimilation of data into NFA permits detailed analysis of ocean-wave physics with higher bandwidths than is possible using either other formulations, such as High-Order Spectral (HOS) methods, or field measurements. A framework is provided for assimilating the wavy and vortical portions of the flow. Nudging is used to assimilate wave data at low wavenumbers, and the wave data at high wavenumbers form naturally through nonlinear interactions, wave breaking, and wind forcing. Similarly, the vertical profiles of the mean vortical flow in the wind and the wind drift are nudged, and the turbulent fluctuations are allowed to form naturally. As a demonstration, the results of a HOS of a JONSWAP wave spectrum are assimilated to study short-crested seas in equilibrium with the wind. Log pr...

Dommermuth, Douglas G; Tran, Vu H; Valenciano, Miguel A

2014-01-01T23:59:59.000Z

314

Direct Power Control of Doubly-Fed Generator Based Wind Turbine Converters to Improve Low Voltage  

E-Print Network [OSTI]

Control (DPC) is discussed for Low Voltage Ride Through (LVRT) of DFIG based wind turbine converters power integration state that doubly fed induction generator (DFIG) controllers should be capable and maintaining dc bus voltage, then the DFIG will stay online during the disturbance. A fast acting controller

Kimball, Jonathan W.

315

Wind dependence of deep ocean ambient noise at low frequencies  

Science Journals Connector (OSTI)

A series of experiments has been carried out using a vertical line array to measure low?frequency ambient noise at deep ocean sites in the Northeast Pacific Ocean. Data in the band from 13 to 300 Hz were processed to obtain the array response directed vertically upward in order to study the noise due to local winds. The results indicate that there are two regimes of behavior depending on the wind speed v with the transition occurring at the onset of wave breaking v?10 kn. The noise level (NL) for a specific wind noise process was related to a power n of the wind speed according to the relationship NL=B+20n?log?v and the model parameters were obtained by fitting the data. The average value over the band was n=0.3 for wind speeds wind?generated noise was determined over the low?frequency band for wind speeds from 10–30 kn. The values are consistent with those of a recent analysis of available noise data [Kewley e t a l. ‘‘Low?frequency wind?generated ambient noise source levels ’’ J. Acoust. Soc. Am. 8 8 1894–1902 (1990)] and the model provides good agreement with wind noise measurements obtained with omni hydrophones in the southern oceans.

N. R. Chapman; J. W. Cornish

1993-01-01T23:59:59.000Z

316

Candidate wind turbine generator site: annual data summary, January 1981-December 1981  

SciTech Connect (OSTI)

Summarized hourly meteorological data for 34 candidate and wind turbine generator sites for calendar year 1981 are presented. These data are collected for the purpose of evaluating the wind energy potential at these sites and are used to assist in selection of potential sites for installation and testing of large wind turbines in electric utility systems. For each site, wind speed, direction, and distribution data are given in eight tables. Use of information from these tables, with information about specific wind turbines, should allow the user to estimate the potential for wind energy production at each site.

Sandusky, W.F.; Buck, J.W.; Renne, D.S.; Hadley, D.L.; Abbey, O.B.

1982-07-01T23:59:59.000Z

317

Zoning for Small Wind: The Importance of Tower Height  

Wind Powering America (EERE)

1 1 Zoning for Small Wind: The Importance of Tower Height An ASES Small Wind Webinar Mick Sagrillo-Wisconsin's Focus on Energy © 2008 by Mick Sagrillo 2 Definitions: rotor L&S Tech. Assoc., Inc. Rotor = "collector" for a wind system 3 Definitions: wind * Wind = the 'fuel' * Wind has two 'components' - Quantity = wind speed (velocity or V) - Quality = 'clean' flowing wind 4 Quantity * = average annual wind speed * Climate, not weather * Akin to annual average sun hours for PV or head and flow for hydro * Wind speed increases with height above ground... * ...Due to diminished ground drag (friction) 5 Power in the wind V³ * Wind speed = V * Power available is proportional to wind speed x wind speed x wind speed - or P ~ V x V x V - or P ~ V ³ * Therefore, 10% V = 33% P * Lesson !

318

Wind energy conversion system  

DOE Patents [OSTI]

The wind energy conversion system includes a wind machine having a propeller connected to a generator of electric power, the propeller rotating the generator in response to force of an incident wind. The generator converts the power of the wind to electric power for use by an electric load. Circuitry for varying the duty factor of the generator output power is connected between the generator and the load to thereby alter a loading of the generator and the propeller by the electric load. Wind speed is sensed electro-optically to provide data of wind speed upwind of the propeller, to thereby permit tip speed ratio circuitry to operate the power control circuitry and thereby optimize the tip speed ratio by varying the loading of the propeller. Accordingly, the efficiency of the wind energy conversion system is maximized.

Longrigg, Paul (Golden, CO)

1987-01-01T23:59:59.000Z

319

Technology Improvement Opportunities for Low Wind Speed Turbines and Implications for Cost of Energy Reduction: July 9, 2005 - July 8, 2006  

SciTech Connect (OSTI)

This report analyzes the status of wind energy technology in 2002 and describes the potential for technology advancements to reduce the cost and increase the performance of wind turbines.

Cohen, J.; Schweizer, T.; Laxson, A.; Butterfield, S.; Schreck, S.; Fingersh, L.; Veers, P.; Ashwill, T.

2008-02-01T23:59:59.000Z

320

Optimization of Wind Turbine Operation  

E-Print Network [OSTI]

inclination angle was about 1°. The spinner anemometer measurements were correlated with wind speed and windOptimization of Wind Turbine Operation by Use of Spinner Anemometer TF Pedersen, NN Sørensen, L Title: Optimization of Wind Turbine Operation by Use of Spinner Anemometer Department: Wind Energy

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

The Influence of Turbulence and Vertical Wind Profile in Wind Turbine Power Curve  

Science Journals Connector (OSTI)

To identify the influence of turbulence and vertical wind profile in wind turbine performance, wind speed measurements at different heights have been ... equipment, specifically a pulsed wave one. The wind profil...

A. Honrubia; A. Vigueras-Rodríguez…

2012-01-01T23:59:59.000Z

322

Hurricane wind fields needed to assess risk to offshore wind farms  

Science Journals Connector (OSTI)

...Scatterplot of maximum landfall winds at wind farm locations (y axis) compared with the peak life cycle wind speed for the same hurricane while...Quantifying the hurricane risk to offshore wind turbines . Proc Natl Acad Sci USA 109 : 3247...

Mark D. Powell; Steven Cocke

2012-01-01T23:59:59.000Z

323

Seismic experiments provide new clues to earthquake wave directionality and growth speed PASADENA, Calif.--In recent years, seismologists thought they were getting a handle on how an earthquake  

E-Print Network [OSTI]

Seismic experiments provide new clues to earthquake wave directionality and growth speed PASADENA that direction. The phenomenon has to do with the basic ways rupture fronts (generating seismic waves

324

A sensitivity study of the WRF model in wind simulation for an area of high wind energy  

Science Journals Connector (OSTI)

The performance of the Weather Research and Forecast (WRF) model in wind simulation was evaluated under different numerical and physical options for an area of Portugal, located in complex terrain and characterized by its significant wind energy resource. The grid nudging and integration time of the simulations were the tested numerical options. Since the goal is to simulate the near-surface wind, the physical parameterization schemes regarding the boundary layer were the ones under evaluation. Also, the influences of the local terrain complexity and simulation domain resolution on the model results were also studied. Data from three wind measuring stations located within the chosen area were compared with the model results, in terms of Root Mean Square Error, Standard Deviation Error and Bias. Wind speed histograms, occurrences and energy wind roses were also used for model evaluation. Globally, the model accurately reproduced the local wind regime, despite a significant underestimation of the wind speed. The wind direction is reasonably simulated by the model especially in wind regimes where there is a clear dominant sector, but in the presence of low wind speeds the characterization of the wind direction (observed and simulated) is very subjective and led to higher deviations between simulations and observations. Within the tested options, results show that the use of grid nudging in simulations that should not exceed an integration time of 2 days is the best numerical configuration, and the parameterization set composed by the physical schemes MM5–Yonsei University–Noah are the most suitable for this site. Results were poorer in sites with higher terrain complexity, mainly due to limitations of the terrain data supplied to the model. The increase of the simulation domain resolution alone is not enough to significantly improve the model performance. Results suggest that error minimization in the wind simulation can be achieved by testing and choosing a suitable numerical and physical configuration for the region of interest together with the use of high resolution terrain data, if available.

David Carvalho; Alfredo Rocha; Moncho Gómez-Gesteira; Carlos Santos

2012-01-01T23:59:59.000Z

325

PHYSICAL REVIEW E 88, 042146 (2013) Uncovering wind turbine properties through two-dimensional stochastic modeling of wind dynamics  

E-Print Network [OSTI]

PHYSICAL REVIEW E 88, 042146 (2013) Uncovering wind turbine properties through two, such as the rated speed of the wind turbine or the descriptive wind speed statistics, can be related to the equations describing the evolution of power production and wind speed at single wind turbines. DOI: 10

Peinke, Joachim

326

On prediction of wind-borne plumes with simple models of turbulent transport  

E-Print Network [OSTI]

of x, and the vertical wind speed of gas above ground wass x 10 Vertical gas velocity, horizontal wind speed = 1 m/ss x 10 Vertical gas velocity, horizontal wind speed = 5 m/s

Schwarz, Katherine; Patzek, Tad; Silin, Dmitriy

2008-01-01T23:59:59.000Z

327

Wind energy conversion system  

SciTech Connect (OSTI)

This patent describes a wind energy conversion system comprising: a propeller rotatable by force of wind; a generator of electricity mechanically coupled to the propeller for converting power of the wind to electric power for use by an electric load; means coupled between the generator and the electric load for varying the electric power drawn by the electric load to alter the electric loading of the generator; means for electro-optically sensing the speed of the wind at a location upwind from the propeller; and means coupled between the sensing means and the power varying means for operating the power varying means to adjust the electric load of the generator in accordance with a sensed value of wind speed to thereby obtain a desired ratio of wind speed to the speed of a tip of a blade of the propeller.

Longrigg, P.

1987-03-17T23:59:59.000Z

328

NREL: Wind Research - NREL's Wind Technology Patents Boost Efficiency and  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

NREL's Wind Technology Patents Boost Efficiency and Lower Costs NREL's Wind Technology Patents Boost Efficiency and Lower Costs March 22, 2013 Wind energy research conducted at the National Wind Technology Center (NWTC) at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) during the last decade has earned the lab two patents, one for adaptive pitch control and one for a resonance blade test system that will ultimately help its industry partners increase the efficiency of wind technologies and reduce the cost of wind energy. The most recent patent for adaptive pitch control for variable-speed wind turbines was granted in May 2012. Variable-speed wind turbines use rotor blade pitch control to regulate rotor speed at the high wind speed limit. Although manufacturers and operators have been interested in developing a nominal pitch to improve

329

Doppler Lidar–Based Wind-Profile Measurement System for Offshore Wind-Energy and Other Marine Boundary Layer Applications  

Science Journals Connector (OSTI)

Accurate measurement of wind speed profiles aloft in the marine boundary layer is a difficult challenge. The development of offshore wind energy requires accurate information on wind speeds above the surface at least at the levels occupied by ...

Yelena L. Pichugina; Robert M. Banta; W. Alan Brewer; Scott P. Sandberg; R. Michael Hardesty

2012-02-01T23:59:59.000Z

330

IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 40, NO. 2, MARCH/APRIL 2004 565 Modeling and Control of a Variable-Speed  

E-Print Network [OSTI]

. The advantages of the proposed system are reduced harmonic injection to power grid, wide speed operation range. It can be directly applied to wind power generators, small-scale hydroelectric generators, stand Identifier 10.1109/TIA.2004.824504 Fig. 1. Traditional wind power generation systems. (a) Variable

Mi, Chunting "Chris"

331

Definition: Wind power | Open Energy Information  

Open Energy Info (EERE)

Wind power Wind power Jump to: navigation, search Dictionary.png Wind power The amount of power available to a wind turbine depends on: air density, wind speed and the swept area of the rotor. While the power is proportional to air density and swept area, it varies with the cube of wind speed, so small changes in wind speed can have a relatively large impact on wind power.[1] View on Wikipedia Wikipedia Definition Wind power is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electrical power, windmills for mechanical power, windpumps for water pumping or drainage, or sails to propel ships. Large wind farms consist of hundreds of individual wind turbines which are connected to the electric power transmission network. Offshore wind is steadier and stronger than on land, and offshore farms

332

Global potential for wind-generated electricity  

Science Journals Connector (OSTI)

...6 MW, deployed offshore, reflecting the greater...incentive to deploy larger turbines to capture the higher wind speeds available in...Electricity-Producing Wind Turbines ( International Electrotechnical...2008 ) Assessing offshore wind resources: An accessible...

Xi Lu; Michael B. McElroy; Juha Kiviluoma

2009-01-01T23:59:59.000Z

333

WIND ENERGY Wind Energ. 2013; 00:112  

E-Print Network [OSTI]

WIND ENERGY Wind Energ. 2013; 00:1­12 DOI: 10.1002/we RESEARCH ARTICLE Model predictive control in wind speed, ensuring certain power gradients, with an insignificant loss in energy production rejection, model predictive control, convex optimization, wind power control, energy storage, power output

334

High-pressure late cycle direct injection of natural gas in a rail medium speed diesel engine  

SciTech Connect (OSTI)

The performance of an Electro-Motive Division (EMD) 567B, two-cylinder locomotive research engine, when operated on high-pressure/late-cycle injection of natural gas, is presented in this paper. A redesign and fabrication of the fuel system was undertaken to facilitate the consumption of natural gas. A small percentage of No.2 diesel fuel (DF-2) was used to ignite the natural gas. Engine performance, while running natural gas, resulted in matching rated speed and power with slightly lower thermal efficiency. Full power was achieved with a ratio of 99 percent natural gas and 1 percent diesel fuel. However, at high natural gas to diesel fuel ratios, audible knock was detected. The primary objective of the project was to establish technical feasibility of, and basic technology for, operating medium-speed rail diesel engines on high-pressure natural gas. Secondary objectives were to attain adequate engine performance levels for rail application, develop a system oriented toward retrofit of in-service locomotives, and realize any potential improvements in thermal efficiency due to use of the high-pressure/late-cycle approach.

Wakenell, J.F.; O'Neal, G.B.; Baker, Q.A.

1987-01-01T23:59:59.000Z

335

How Distributed Wind Works | Department of Energy  

Energy Savers [EERE]

Basics How Distributed Wind Works How Distributed Wind Works Residential Small wind turbines can be used in residential settings to directly offset electricity usage using net...

336

Wind Technology Advancements and Impacts on Western Wind Resources (Presentation)  

SciTech Connect (OSTI)

Robi Robichaud made this presentation at the Bureau of Land Management West-wide Wind Opportunities and Constraints Mapping (WWOCM) Project public meeting in Denver, Colorado in September 2014. This presentation outlines recent wind technology advancements, evolving turbine technologies, and industry challenges. The presentation includes maps of mean wind speeds at 50-m, 80-m, and 100-m hub heights on BLM lands. Robichaud also presented on the difference in mean wind speeds from 80m to 100m in Wyoming.

Robichaud, R.

2014-09-01T23:59:59.000Z

337

Non-Directed Line-of-Sight Visible Light System providing High-Speed and Robustness to Ambient Light  

Science Journals Connector (OSTI)

We demonstrate the first optical wireless link operating in non-direct line-of-sight configuration over typical room distances, with data-rate up to 200 Mbit/s at acceptable...

Cossu, Giulio; Khalid, Amir M; Corsini, Raffaele; Ciaramella, Ernesto

338

National Wind Technology Center (Fact Sheet), National Wind Technology...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

hydrokinetic (MHK) energy devices are high-force, low-speed machines, similar to wind turbines that convert the kinetic energy of a moving fluid into electrical energy....

339

Performance of PI controller for control of active and reactive power in DFIG operating in a grid-connected variable speed wind energy conversion system  

Science Journals Connector (OSTI)

Due to several factors, wind energy becomes an essential type of electricity generation. The share of this type of energy in the network is becoming increasingly important. The objective of this work is to presen...

Azzouz Tamaarat; Abdelhamid Benakcha

2014-09-01T23:59:59.000Z

340

Innovative Power?Augmentation?Guide?Vane Design of Wind?Solar Hybrid Renewable Energy Harvester for Urban High Rise Application  

Science Journals Connector (OSTI)

To generate greater quantities of energy from wind the most efficient solution would be by increasing the wind speed. Also due to the decreasing number of economic wind energy sites there are plans to place wind turbines closer to populated areas. To site wind turbines out from rural areas the current problems of wind turbines need to be resolved especially visual impact poor starting behaviour in low wind speeds noise and danger caused by blade failure. In this paper a patented wind?solar hybrid renewable energy harvester is introduced. It is a compact system that integrates and optimizes several green elements and can be built on the top (or between upper levels) of high rise buildings or structures. This system can be used in remote and urban areas particularly at locations where the wind speed is lower and more turbulent. It overcomes the inferior aspect on the low wind speed by guiding and increasing the speed of the high altitude free?stream wind through fixed or yaw?able power?augmentation?guide?vane (PAGV) before entering the wind turbine (straight?bladed vertical axis wind turbine VAWT in this project) at center portion. PAGV is a new and innovative design where its appearance or outer design can be blended into the building architecture without negative visual impact. From the studies it is shown that the wind speed increment in the PAGV can be produced according to the Bernoulli’s principle. Computational fluid dynamics (CFD) simulation is used to optimize the geometry of the PAGV and the simulation results demonstrated the technical possibility of this innovative concept. The PAGV replaces the free air?stream from wind by multiple channels of speed?increased and directional?controlled air?stream. With the PAGV this lift?type VAWT can be self?started and its size can be reduced for a given power output. The design is also safer since the VAWT is enclosed by the PAGV. By integrating the PAGV with the VAWT (the diameter and height of PAGV are 2 times larger than the VAWT’s) the predicted power generated (at free?stream wind speed ?=?3.5? m / s ) is 1.25 times higher than the VAWT that has the same size as the PAGV. This new wind energy generation configuration should generate interest in the international market even for regions with weaker winds. The correlation between CFD simulation and wind tunnel test will be carried out and reported elsewhere.

Chong Wen Tong; M. Z. Zainon; Poh Sin Chew; Soo Chun Kui; Wee Seng Keong; Pan Kok Chen

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

RIS0-M-2432 SIMPLIFIED LAWS OF SIMIALRITY FOR WIND TURBINE ROTORS  

E-Print Network [OSTI]

comments are presented on comparison of stall-and pitch-regu- lated wind turbines and on two speed Shape factor (Weibull) Rotational speed Power Rotor radius Wind speed Rotor tip speed Tip speed ratio V is the wind speed at hub height, j> is the air density, #12;0 . 5 u ·p C

342

Wind Gallery | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

(shown here), concrete, or steel lattice. Supports the structure of the turbine. Because wind speed increases with height, taller towers enable turbines to capture more energy and...

343

NREL: Wind Research - Offshore Wind Resource Characterization  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Offshore Wind Resource Characterization Offshore Wind Resource Characterization Map of the United States, showing the wind potential of offshore areas across the country. Enlarge image US offshore wind speed estimates at 90-m height NREL scientists and engineers are leading efforts in resource mapping, remote sensor measurement and development, and forecasting that are essential for the development of offshore wind. Resource Mapping For more than 15 years, NREL's meteorologists, engineers, and Geographic Information System experts have led the production of wind resource characterization maps and reports used by policy makers, private industry, and other government organizations to inform and accelerate the development of wind energy in the United States. Offshore wind resource data and mapping has strategic uses. As with terrestrial developments, traditional

344

Analysis of an extremely fast valve opening camless system to improve transient performance in a turbocharged high speed direct injection diesel engine  

Science Journals Connector (OSTI)

This article describes a theoretical study on the performance optimisation of a high speed direct injection turbocharged diesel engine equipped with an electro-hydraulic variable valve actuation 'camless' system. This system provides extremely fast valve opening and closing slopes. Thus, its potential for recovering part of the energy lost in the valves by reducing gas flow sonic conditions in the valve throat has been investigated. This study has been mainly focused on the analysis of engine performance during a load transient evolution, but the full load steady state attained at the end of the load transient has been also discussed. The results of this investigation have confirmed important improvements in engine performance during the load transient owing to less energy being lost across the valves, which directly results in more energy being available in the turbine. This benefit has also been observed at full load steady state conditions.

J. Benajes; J.R. Serrano; V. Dolz; R. Novella

2009-01-01T23:59:59.000Z

345

Synoptic and local influences on boundary layer processes, with an application to California wind power  

E-Print Network [OSTI]

corresponding to extreme winds for di?erent stations andin turn would lead to extreme downscaled wind speed changeextreme quintiles or more exacting classi?cations of wind

Mansbach, David K.

2010-01-01T23:59:59.000Z

346

Turbine Inflow Characterization at the National Wind Technology Center  

SciTech Connect (OSTI)

Utility-scale wind turbines operate in dynamic flows that can vary significantly over timescales from less than a second to several years. To better understand the inflow to utility-scale turbines, two inflow towers were installed and commissioned at the National Renewable Energy Laboratory's (NREL) National Wind Technology Center near Boulder, Colorado, in 2011. These towers are 135 m tall and instrumented with a combination of sonic anemometers, cup anemometers, wind vanes, and temperature measurements to characterize the inflow wind speed and direction, turbulence, stability and thermal stratification to two utility-scale turbines. Herein, we present variations in mean and turbulent wind parameters with height, atmospheric stability, and as a function of wind direction that could be important for turbine operation as well as persistence of turbine wakes. Wind speed, turbulence intensity, and dissipation are all factors that affect turbine performance. Our results show that these all vary with height across the rotor disk, demonstrating the importance of measuring atmospheric conditions that influence wind turbine performance at multiple heights in the rotor disk, rather than relying on extrapolation from lower levels.

Clifton, A.; Schreck, S.; Scott, G.; Kelley, N.; Lundquist, J. K.

2012-01-01T23:59:59.000Z

347

Demonstration of wind turbine. Final technical report at grant program  

SciTech Connect (OSTI)

Proposal F-602 is a demonstration of a commercially available wind-electric device - an Enertech Corp. Series 1800 model wind turbine. The demonstration site selected was the New Directions school campus, a public school facility, in Sarasota, Florida. During testing, an investigation of the wind power potential for the area was undertaken. In addition, negotiations with the Florida Power and Light Company for parallel operation of the wind system (utility interface), were initiated. An Operating Agreement contract is now pending approval by the Sarasota County School Board. The results to date, of this site's wind power potential, have been well below computational expectancies based upon wind speed data for the area. Analysis will continue, to determine the cause of the windplant's low net output.

Pendola, W. Jr.

1982-06-01T23:59:59.000Z

348

An Evaluation of the Cascaded H-Bridge Multilevel Inverter Topology For Direct-Drive Synchronous Wind Farm Applications.  

E-Print Network [OSTI]

?? A key driver in the recent success of wind has been engineering advances that have lead to improved economics. Many of these advances have… (more)

Callison, Gerald Robert

2006-01-01T23:59:59.000Z

349

Performance of propeller wind turbines  

SciTech Connect (OSTI)

Presented herein is a parametric study of the performance of propeller wind turbines with realistic drag/lift ratios. Calculations were made using the complete Glauert vortex blade element theory in annular streamtube elements with the complete turbine performance being the sum of the elemental results up to a specified tip speed ratio. The objective here is to exhibit a new computational technique which yields performance directly when tangential speed ratio and section aerodynamic characteristics are specified. It was found that for a tip speed ratio of 4, turbines with drag/lift ratios of 0.00 and 0.01 had power coefficients of 0.575 and 0.55, respectively. The off-design performance of the finite drag/lift was far better than that of their zero drag counterparts, except in a + or - 20% region about the design conditions. Tolerance to off-design operation increased with decreasing tip speed ratios so that the annual energy capture for tip speed ratios between 2 and 4 was about 87% of the ideal turbine value. The results are intended to provide a basis for re-evaluation of the power range classes of fixed pitch turbines and design tip speed ratios.

Wortman, A.

1983-11-01T23:59:59.000Z

350

NREL: Wind Research - Site Wind Resource Characteristics  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Site Wind Resource Characteristics Site Wind Resource Characteristics A graphic showing the location of National Wind Technology Center and its wind power class 2. Click on the image to view a larger version. Enlarge image This graphic shows the wind power class at the National Wind Technology Center. You can download a printable copy. The National Wind Technology Center (NWTC) is on the Great Plains just miles from the Rocky Mountains. The site is flat and covered with short grasses. The terrain and lack of obstructions make the site highly suitable for testing wind turbines. Take a tour of the NWTC and its facilities to better understand its location and layout. Another prime feature of the NWTC is the strong directionality of the wind - most of the strong winds come within a few degrees of 285°. West of

351

Analysis of Temporal and Spatial Characteristics on Output of Wind Farms with Doubly Fed Induction Generator Wind Turbines  

Science Journals Connector (OSTI)

Due to the large number of wind turbines and covering too large area in a large wind farm, wake effects among wind turbines and wind speed time delays will have a greater impact of wind farms models. Taking wind farms with doubly fed induction generator(DFIG) ... Keywords: wind farm, modeling, temporal and spatial characteristics, DFIG, output characteristics

Shupo Bu; Xunwen Su

2012-12-01T23:59:59.000Z

352

Modeling of wind farm controllers Poul Srensen1  

E-Print Network [OSTI]

and dead band. Two types of wind farms are presented. The first using variable speed wind turbines with doubly fed induction generators and fixed speed wind turbines with active stall control. Keywords: wind the wind turbines have increased in size, the costs have been reduced, and the controllability developed

353

Design of a wind turbine-generator system considering the conformability to wind velocity fluctuations  

SciTech Connect (OSTI)

The conformability of the rated power output of the wind turbine-generator system and of the wind turbine type to wind velocity fluctuations are investigated with a simulation model. The authors examine three types of wind turbines: the Darrieus-Savonius hybrid, the Darrieus proper and the Propeller. These systems are mainly operated at a constant tip speed ratio, which refers to a maximum power coefficient points. As a computed result of the net extracting power, the Darrieus turbine proper has little conformability to wind velocity fluctuations because of its output characteristics. As for the other turbines, large-scale systems do not always have an advantage over small-scale systems as the effect of its dynamic characteristics. Furthermore, it is confirmed that the net extracting power of the Propeller turbine, under wind direction fluctuation, is much reduced when compared with the hybrid wind turbine. Thus, the authors conclude that the appropriate rated power output of the system exists with relation to the wind turbine type for each wind condition.

Wakui, Tetsuya; Hashizume, Takumi; Outa, Eisuke

1999-07-01T23:59:59.000Z

354

Structural responses and power output of a wind turbine are strongly affected by the wind field acting on the wind turbine. Knowledge about the wind field and its  

E-Print Network [OSTI]

ABSTRACT Structural responses and power output of a wind turbine are strongly affected by the wind affect the power output and structural responses of a wind turbine. Wind field characteristics are conventionally described by time averaged features, such as mean wind speed, turbulence intensity and power

Stanford University

355

Wind/Wave Misalignment in the Loads Analysis of a Floating Offshore Wind Turbine: Preprint  

SciTech Connect (OSTI)

Wind resources far from the shore and in deeper seas have encouraged the offshore wind industry to look into floating platforms. The International Electrotechnical Commission (IEC) is developing a new technical specification for the design of floating offshore wind turbines that extends existing design standards for land-based and fixed-bottom offshore wind turbines. The work summarized in this paper supports the development of best practices and simulation requirements in the loads analysis of floating offshore wind turbines by examining the impact of wind/wave misalignment on the system loads under normal operation. Simulations of the OC3-Hywind floating offshore wind turbine system under a wide range of wind speeds, significant wave heights, peak-spectral periods and wind/wave misalignments have been carried out with the aero-servo-hydro-elastic tool FAST [4]. The extreme and fatigue loads have been calculated for all the simulations. The extreme and fatigue loading as a function of wind/wave misalignment have been represented as load roses and a directional binning sensitivity study has been carried out. This study focused on identifying the number and type of wind/wave misalignment simulations needed to accurately capture the extreme and fatigue loads of the system in all possible metocean conditions considered, and for a down-selected set identified as the generic US East Coast site. For this axisymmetric platform, perpendicular wind and waves play an important role in the support structure and including these cases in the design loads analysis can improve the estimation of extreme and fatigue loads. However, most structural locations see their highest extreme and fatigue loads with aligned wind and waves. These results are specific to the spar type platform, but it is expected that the results presented here will be similar to other floating platforms.

Barj, L.; Stewart, S.; Stewart, G.; Lackner, M.; Jonkman, J.; Robertson, A.

2014-02-01T23:59:59.000Z

356

Double row loop-coil configuration for high-speed electrodynamic maglev suspension, guidance, propulsion and guideway directional switching  

DOE Patents [OSTI]

A stabilization and propulsion system are disclosed comprising a series of loop-coils arranged in parallel rows wherein two rows combine to form one of two magnetic rails. Levitation and lateral stability are provided when the induced field in the magnetic rails interacts with the superconducting magnets mounted on the magnetic levitation vehicle. The loop-coils forming the magnetic rails have specified dimensions and a specified number of turns and by constructing differently these specifications, for one rail with respect to the other, the angle of tilt of the vehicle can be controlled during directional switching. Propulsion is provided by the interaction of a traveling magnetic wave associated with the coils forming the rails and the superconducting magnets on the vehicle. 12 figs.

He, J.; Rote, D.M.

1996-05-21T23:59:59.000Z

357

Aerodynamic interference between two Darrieus wind turbines  

SciTech Connect (OSTI)

The effect of aerodynamic interference on the performance of two curved bladed Darrieus-type vertical axis wind turbines has been calculated using a vortex/lifting line aerodynamic model. The turbines have a tower-to-tower separation distance of 1.5 turbine diameters, with the line of turbine centers varying with respect to the ambient wind direction. The effects of freestream turbulence were neglected. For the cases examined, the calculations showed that the downwind turbine power decrement (1) was significant only when the line of turbine centers was coincident with the ambient wind direction, (2) increased with increasing tipspeed ratio, and (3) is due more to induced flow angularities downstream than to speed deficits near the downstream turbine.

Schatzle, P.R.; Klimas, P.C.; Spahr, H.R.

1981-04-01T23:59:59.000Z

358

Wind Rose Bias Correction  

Science Journals Connector (OSTI)

Wind rose summaries, which provide a basis for understanding and evaluating the climatological behavior of local wind, have a directional bias if a conventional method is used in their generation. Three techniques used to remove this bias are ...

Scott Applequist

2012-07-01T23:59:59.000Z

359

Wind energy | Open Energy Information  

Open Energy Info (EERE)

(Redirected from Wind) (Redirected from Wind) Jump to: navigation, search Wind energy is a form of solar energy.[1] Wind energy (or wind power) describes the process by which wind is used to generate electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. A generator can convert mechanical power into electricity[2]. Mechanical power can also be utilized directly for specific tasks such as pumping water. The US DOE developed a short wind power animation that provides an overview of how a wind turbine works and describes the wind resources in the United States. Contents 1 Wind Energy Basics 1.1 Equation for Wind Power 2 DOE Wind Programs and Information 3 Worldwide Installed Capacity 3.1 United States Installed Capacity 4 Wind Farm Development 4.1 Land Requirements

360

Sustainable Development and Kish Island Environment Protection, using Wind Energy  

E-Print Network [OSTI]

Abstract—Kish Islands in South of Iran is located in coastal water near Hormozgan Province. Based on the wind 3-hour statistics in Kish station, the mean annual windspeed in this Island is 8.6 knot (4.3 m/s). The maximum windspeed recorded in this stations 47 knot (23.5 m/s). In 45.7 percent of recorded times, windspeed has been Zero or less than 8 knot which is not suitable to use the wind energy. But in 54.3 percent of recorded times, windspeed has been more than 8 knot and suitable to use wind energy to run turbines. In 40.2 percent of recorded times, windspeed has been between 8 to 16 knot, in 13 percent of times between 16 to 24 knot and in 1 percent of times it has been higher than 24 knot. In this station, the direction of winds higher than 8 is west and wind direction in Kish station is stable in most times of the year.With regard to high – speed and stable direction winds during the year and also shallow coasts near this is land, it is possible to build offshore wind farms near Kish Island and utilize wind energy produce the electricity required in this Island during most of the year.

Amir Gandomkar

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Wind Resource Assessment of Gujarat (India)  

SciTech Connect (OSTI)

India is one of the largest wind energy markets in the world. In 1986 Gujarat was the first Indian state to install a wind power project. In February 2013, the installed wind capacity in Gujarat was 3,093 MW. Due to the uncertainty around existing wind energy assessments in India, this analysis uses the Weather Research and Forecasting (WRF) model to simulate the wind at current hub heights for one year to provide more precise estimates of wind resources in Gujarat. The WRF model allows for accurate simulations of winds near the surface and at heights important for wind energy purposes. While previous resource assessments published wind power density, we focus on average wind speeds, which can be converted to wind power densities by the user with methods of their choice. The wind resource estimates in this study show regions with average annual wind speeds of more than 8 m/s.

Draxl, C.; Purkayastha, A.; Parker, Z.

2014-07-01T23:59:59.000Z

362

Synoptic and local influences on boundary layer processes, with an application to California wind power  

E-Print Network [OSTI]

th percentiles of daily wind speeds (vertical axis) largelyand warm SST. Mean vertical pro?les of wind speed from EPICspeed at the wind farm sites, since inversion strength is largely controlled by the vertical

Mansbach, David K.

2010-01-01T23:59:59.000Z

363

Operational behavior of a double-fed permanent magnet generator for wind turbines  

E-Print Network [OSTI]

Greater efficiency in wind turbine systems is achieved by allowing the rotor to change its rate of rotation as the wind speed changes. The wind turbine system is decoupled from the utility grid and a variable speed operation ...

Reddy, Sivananda Kumjula

2005-01-01T23:59:59.000Z

364

Wind Turbine Blade Design  

K-12 Energy Lesson Plans and Activities Web site (EERE)

Blade engineering and design is one of the most complicated and important aspects of modern wind turbine technology. Engineers strive to design blades that extract as much energy from the wind as possible throughout a range of wind speeds and gusts, yet are still durable, quiet and cheap. A variety of ideas for building turbines and teacher handouts are included in this document and at the Web site.

365

Thermodynamic analysis of energy conversion and transfer in hybrid system consisting of wind turbine and advanced adiabatic compressed air energy storage  

Science Journals Connector (OSTI)

Abstract A simulation model consisting of wind speed, wind turbine and AA-CAES (advanced adiabatic compressed air energy storage) system is developed in this paper, and thermodynamic analysis on energy conversion and transfer in hybrid system is carried out. The impacts of stable wind speed and unstable wind speed on the hybrid system are analyzed and compared from the viewpoint of energy conversion and system efficiency. Besides, energy conversion relationship between wind turbine and AA-CAES system is investigated on the basis of process analysis. The results show that there are several different forms of energy in hybrid system, which have distinct conversion relationship. As to wind turbine, power coefficient determines wind energy utilization efficiency, and in AA-CAES system, it is compressor efficiency that mainly affects energy conversion efficiencies of other components. The strength and fluctuation of wind speed have a direct impact on energy conversion efficiencies of components of hybrid system, and within proper wind speed scope, the maximum of system efficiency could be expected.

Yuan Zhang; Ke Yang; Xuemei Li; Jianzhong Xu

2014-01-01T23:59:59.000Z

366

Description of the Columbia Basin Wind Energy Study (CBWES)  

SciTech Connect (OSTI)

The purpose of this Technical Report is to provide background information about the Columbia Basin Wind Energy Study (CBWES). This study, which was supported by the U.S. Department of Energy’s Wind and Water Power Program, was conducted from 16 November 2010 through 21 March 2012 at a field site in northeastern Oregon. The primary goal of the study was to provide profiles of wind speed and wind direction over the depth of the boundary layer in an operating wind farm located in an area of complex terrain. Measurements from propeller and vane anemometers mounted on a 62 m tall tower, Doppler Sodar, and Radar Wind Profiler were combined into a single data product to provide the best estimate of the winds above the site during the first part of CBWES. An additional goal of the study was to provide measurements of Turbulence Kinetic Energy (TKE) near the surface. To address this specific goal, sonic anemometers were mounted at two heights on the 62 m tower on 23 April 2011. Prior to the deployment of the sonic anemometers on the tall tower, a single sonic anemometer was deployed on a short tower 3.1 m tall that was located just to the south of the radar wind profiler. Data from the radar wind profiler, as well as the wind profile data product are available from the Atmospheric Radiation Measurements (ARM) Data Archive (http://www.arm.gov/data/campaigns). Data from the sonic anemometers are available from the authors.

Berg, Larry K.; Pekour, Mikhail S.; Nelson, Danny A.

2012-10-01T23:59:59.000Z

367

Wind energy resources analysis of Western Greece coast in terms of sustainable environmental indicators and towards their community-based exploitation in South-East Europe  

Science Journals Connector (OSTI)

Wind energy resources in the Ionian-Adriatic coast of South-East Europe were analyzed. Status of wind energy development in the countries of Greece Albania Montenegro Bosnia-Herzegovina and Croatia and regions of moderate and high wind potential at their west coasts were reviewed. The feasibility of the application of specific wind turbine generators with lower cut-in cut-out and rated speeds in moderate wind fields was investigated. The wind speed and direction as well as the availability the duration and the diurnal variation of several coastal sites in Western Greece were assessed and the results were statistically analyzed as time-series or with the Weibull probability distribution function. The mean wind power densities were less than 200?W?m?2 at 10?m suggesting the limiting suitability of the sites for the usual wind energy applications. However further technical-economical analysis revealed that the recent technological turbine improvements with lower cut-in and rated speeds make wind power viable even at moderate wind fields. Environmental indicators like energy payback period and avoided greenhouse emissions were determined to be significant for the utilization of wind energy resources in these coastal areas. Since the region is important for sea-related activities the implementation of wind energy applications in the frame of cross-border cooperation should be prioritized.

2013-01-01T23:59:59.000Z

368

Ris R 1068EN Extreme Winds  

E-Print Network [OSTI]

Ris R 1068EN Extreme Winds in Denmark Leif Kristensen and Ole Rathmann Ris National Laboratory of this investigationis to study, on basis of climatologicalrecords, how large extreme wind speeds are in various parts;Abstract Wind-speed data from four sites in Denmark have been analyzed in order to obtain estimates

369

Section 4 - Wind  

Science Journals Connector (OSTI)

The exploitation of wind power for useful energy is both a practice dating back to ancient times and a key component of today’s effort to substitute renewable energy sources for fossil fuels. Use of wind energy has progressed historically through three stages. First came the use of wind for propulsion of water craft via sails. Then the windmill came into use in agriculture, originally to grind grain and then later to drain water from fields or raise it from a well. Finally (much later) came the use of wind to power turbines to generate electricity. The two historic uses of wind power, sailing ships and windmills, are both still in existence today, though on a lesser scale than in the past. The earliest use of the sail is thought to have occurred more than 5,000 years ago on the Nile River and in the Mediterranean Sea. A major advance in sailing came in the era of the Roman Empire, as early as the 2nd century A.D., with the appearance on the Mediterranean of the lateen (triangular) sail, which was capable of taking the wind on either side and thus could sail into the wind, as opposed to the earlier square sail which could only sail with the wind. This technology is believed to have originated with Arab sailors on the Red Sea about 200 years earlier. The use of multiple triangular sails, in combination with square sails, led to the Age of Sail, during which sailing vessels were employed for global exploration, international trade, and naval warfare. The ultimate in wind-powered ships were the clipper ships of the mid 19th century, famous for their high speed, elegant design, and graceful appearance. Ironically, the finest clipper ships appeared just as the Age of Sail was in its twilight years, having been overtaken by the development of the steam-powered ship. The classic European windmill first appeared in the Middle Ages, probably in the 12th century. A written record of one in England dates from the 1180s. The common type was the tower mill, which was developed shortly afterward. It became known as the Dutch windmill because it was ubiquitous in that country, and even today it is a popular symbol of the Dutch nation. The windmill influenced the topography of the Netherlands in that it was widely used to provide the power to reclaim submerged land. The windmill also was reported in China at about the same time it emerged in Europe, though it may have developed even earlier. In the United States the so-called American farm or American-style windmill became a familiar sight from the middle of the 19th century onward, especially in the developing Western region. It was used to provide power to raise well water and to run farm machinery. New technology enabled it to turn its wheel to adjust to changing wind direction, and also to restrict the wheel speed so that the blades would not be destroyed during storms. The use of steel rather than wood as the blade material was a later refinement. This type of windmill eventually spread far beyond the U.S. borders to be used globally. The beginnings of the use of wind power to generate electricity came in the late 1880s and early 1890s, through the work of Charles Brush in the U.S. and Poul la Cour in Denmark. Brush modified a windmill to operate a DC generator, creating what is considered to be the first wind power plant. The experiments of la Cour with wind turbines laid the foundation for modern wind energy technology. In the 1920s the U.S. wind pioneer Marcellus Jacobs developed the first commercial propeller-type rotor for a wind turbine. Companies such as his Jacobs Wind continued on the path established by Brush of modifying existing windmills to provide power to drive DC generators, especially for use by farms that were not on the electrical grid prior to the coming of widespread rural electrification. Another major development of the 1920s was the vertical axis wind turbine (VAWT), which was patented by the French engineer Georges J. M. Darrieus. This new type of wind turbine had a distinctive “eggbeater”or “skipping rope” design, in contrast with the horizontal a

Cutler J. Cleveland; Christopher Morris

2014-01-01T23:59:59.000Z

370

High-Order Sliding Mode Control of DFIG-Based Wind Turbines  

Science Journals Connector (OSTI)

Actually, variable speed wind turbines are continuously increasing their market share, since it is possible to track the changes in wind speed by adapting shaft speed, and thus maintaining optimal power genera...

Mohamed Benbouzid

2014-01-01T23:59:59.000Z

371

A doubly-fed permanent magnet generator for wind turbines  

E-Print Network [OSTI]

Optimum extraction of energy from a wind turbine requires that turbine speed vary with wind speed. Existing solutions to produce constant-frequency electrical output under windspeed variations are undesirable due to ...

Thomas, Andrew J. (Andrew Joseph), 1981-

2004-01-01T23:59:59.000Z

372

Control of wind generator associated to a flywheel energy storage system  

Science Journals Connector (OSTI)

In this paper, a doubly fed variable speed wind induction generator connected to the grid associated to a flywheel energy storage system (FESS) is investigated. The dynamic behaviour of a wind generator, including the models of the wind turbine (aerodynamic), the doubly fed induction generator (DFIG), a ac/ac direct converter, the converter control (algorithm of VENTURINI) and the power control of this system, is studied. Also investigated is a control method of the FESS system, which consists of the classical squirrel-cage induction machine supplied off the variable speed wind generator (VSWG) through a rectifier–inverter cascade arrangement. Simulation results obtained on the basis of the dynamic models of the wind generator are presented, for different operating points, to demonstrate the performance of the proposed system.

K. Ghedamsi; D. Aouzellag; E.M. Berkouk

2008-01-01T23:59:59.000Z

373

Development of an Offshore Direct-Drive Wind Turbine Model by Using a Flexible Multibody Simulation (Poster)  

SciTech Connect (OSTI)

Modern wind turbines are complex, highly-coupled systems. The dynamic interaction between various components is especially pronounced for multi-megawatt wind turbines. As a result, design process is generally split in several phases. First step consists of creating a global aero-elastic model that includes essential dynamics of structural components using the minimum-possible number of degrees of freedom (d.o.f.). The most important simplifications concern drivetrain and rotor-nacelle assembly (RNA). This approach has been shown valid for several wind turbine configurations. Nevertheless, with increasing size of wind turbines, any simplified design approach must be validated. The present work deals with the comparison and validation of the two modeling approaches for directdrive offshore wind turbines. ARNA/drivetrain model idealized as collection of lumped masses and springs is compared to a detailed Finite Element Method (FEM) based model. The comparison between models focuses on dynamic loads concerning drivetrain system. The comparison is performed in several operational conditions in order to explore the range of validity of the simplified model. Finally, the paper proposes a numerical-based workflow to assess the validity of simplified models of RNA/drivetrain in an aero-elastic global WT model.

Bergua, R.; Jove, J.; Campbell, J.; Guo, Y.; Van Dam, J.

2014-05-01T23:59:59.000Z

374

Dynamic valuation model For wind development in regard to land value, proximity to transmission lines, and capacity factor  

E-Print Network [OSTI]

Developing a wind farm involves many variables that can make or break the success of a potential wind farm project. Some variables such as wind data (capacity factor, wind rose, wind speed, etc.) are readily available in ...

Nikandrou, Paul

2009-01-01T23:59:59.000Z

375

Models for Assessing Power Fluctuations from Large Wind Farms N. A. Cutululis1)  

E-Print Network [OSTI]

typical and worst case power fluctuations using the geographical sitting of wind turbines as an input comprehensive, with one year of wind speeds and power from all individual wind turbines in the wind farms of the fluctuating nature of wind speeds, the increasing use of wind turbines for power generation has caused more

376

Wind News | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

Wind News Wind News Wind News RSS February 7, 2011 Salazar, Chu Announce Major Offshore Wind Initiatives Strategic plan, $50 million in R&D funding, identified Wind Energy Areas will speed offshore wind energy development December 16, 2010 Department of Energy Finalizes Loan Guarantee to Support World's Largest Wind Project 845-Megawatt Wind Facility Will Create Hundreds of Jobs and Avoid Over 1.2 Million Tons of Carbon Dioxide Annually October 29, 2010 Statement by Energy Secretary Steven Chu on Today's Grand Opening of the Nordex Manufacturing Facility in Jonesboro, Arkansas Recovery Act investment creates jobs, helps lay the foundation for a clean energy economy September 13, 2010 DOE Announces More than $5 Million to Support Wind Energy Development Funds to Enhance Short-Term Wind Forecasting and Accelerate Midsize Wind

377

First direct measurements of formaldehyde flux via eddy covariance: implications for missing in-canopy formaldehyde sources  

E-Print Network [OSTI]

correlation plot for vertical wind speed (w) with both HCHOtemperature with vertical wind speed during half-hour? w · c where w is the vertical wind speed, c is the tracer

2011-01-01T23:59:59.000Z

378

NREL: Wind Research - Gaia-Wind's 11 Kilowatt Wind Turbine Testing and  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Gaia-Wind's 11 Kilowatt Wind Turbine Testing and Results Gaia-Wind's 11 Kilowatt Wind Turbine Testing and Results A video of Gaia-Wind's 11-kW wind turbine. Text Version As part of the National Renewable Energy Laboratory and U.S. Department of Energy (NREL/DOE) Independent Testing project, NREL tested Gaia-Wind's 11-kilowatt (kW) small wind turbine at the National Wind Technology Center (NWTC). Gaia-Wind's turbine is a three-phase induction generator that operates at 480 volts. The turbine's downwind rotor has a 13-meter diameter, and its tower is 18 meters tall. The two-bladed, oversized rotor is designed for low to moderate wind speeds. Testing Summary The summary of the tests is below with the final reports. Cumulative Energy Production 6/11/2008: 210; 6/13/2008: 528; 6/16/2008: 716; 6/18/2008: 731; 6/19/2008:

379

Blind Test 2 calculations for two in-line model wind turbines where the downstream turbine operates at various rotational speeds  

Science Journals Connector (OSTI)

Abstract In this paper we report on the results of the Blind Test 2 workshop, organized by Norcowe and Nowitech in Trondheim, Norway in October 2012. This workshop was arranged in order to find out how well wind turbine simulation models perform when applied to two turbines operating in line. Modelers with a suitable code were given boundary conditions of a wind tunnel test performed in the large wind tunnel facility at the Department of Energy and Process Engineering, at NTNU Trondheim, where two almost identical model turbines with a diameter of about 0.9?m had been tested under various operating conditions. A detailed geometry specification of the models could be downloaded and the modelers were invited to submit the calculation without knowing the experimental results in advance. Nine different contributions from eight institutions were received, representing a wide range of simulation models, such as a LES coupled with an actuator line rotor model, RANS using an actuator disc, U-RANS models applied to fully resolved turbine model geometries, as well as a vortex panel method. The comparison showed a larger than expected scatter on the performance calculation of the upstream turbine (±20%), and an even higher uncertainty for the downstream turbine, especially at operating conditions close to the runaway point. The modelers were requested to document the wake development downstream of the second turbine, the development behind the first turbine had been the challenge for a previous blind test (see Krogstad and Eriksen [17]). Mean flow calculations reported at X = 1D downstream of the second turbine showed that the models which fully resolved boundary layers on the rotor surface performed best. Including the tower and the hub in the simulation improved the accuracy of the predictions and is essential in capturing the important asymmetries that develop in the wake. These turbine details strongly influence the development near the center of the wake, but are often omitted in simulations in order to incorporate simplifying symmetry conditions in the calculations. Further from the rotor, at X = 4D, the LES simulations coupled to actuator line rotor models performed well and were able to capture the main features of the mean and turbulent flows, while RANS models using actuator disc models showed limitations especially in predicting correctly the turbulent kinetic energy.

Fabio Pierella; Per-Ĺge Krogstad; Lars Sćtran

2014-01-01T23:59:59.000Z

380

Direct  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

interactions, and the pollutant emission is hence directly proportional to the bulk neutral density. Simultaneously monitoring the total emission at 1040 nm and the...

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Dynamic analysis of a 5 megawatt offshore floating wind turbine  

E-Print Network [OSTI]

wind turbine. Rating Control Rotor Radius Rated Wind Speed Towerwind turbine is used in this design, however there are slight modifications of the tower.of the tower. Figure 2.3: NREL 5 MW Reference Wind Turbine [

Harriger, Evan Michael

2011-01-01T23:59:59.000Z

382

Electric power from offshore wind via synoptic-scale interconnection  

Science Journals Connector (OSTI)

...hub-height of modern offshore wind turbines. Our extrapolation...output of an offshore turbine at each selected station with wind speed measurements...Practical commercial offshore wind developments...minimum of 100 turbines at each location...

Willett Kempton; Felipe M. Pimenta; Dana E. Veron; Brian A. Colle

2010-01-01T23:59:59.000Z

383

Analysis of the effects of integrating wind turbines into a conventional utility: a case study. Final report  

SciTech Connect (OSTI)

The impact on a utility incorporating wind turbine generation due to wind speed sampling frequency, wind turbine performance model, and wind speed forecasting accuracy is examined. The utility analyzed in the study was the Los Angeles Department of Water and Power and the wind turbine assumed was the MOD-2. The sensitivity of the economic value of wind turbine generation to wind speed sampling frequency and wind turbine modeling technique is examined as well as the impact of wind forecasting accuracy on utility operation and production costs. Wind speed data from San Gorgonio Pass, California during 1979 are used to estimate wind turbine performance using four different simulation methods. (LEW)

Goldenblatt, M.K.; Wegley, H.L.; Miller, A.H.

1982-08-01T23:59:59.000Z

384

Analysis of the effects of integrating wind turbines into a conventional utility: a case study. Revised final report  

SciTech Connect (OSTI)

The impact on a utility incorporating wind turbine generation due to wind speed sampling frequency, wind turbine performance model, and wind speed forecasting accuracy is examined. The utility analyzed in this study was the Los Angeles Department of Water and Power, and the wind turbine assumed was the MOD-2. The sensitivity of the economic value of wind turbine generation to wind speed sampling frequency and wind turbine modeling technique is examined as well as the impact of wind forecasting accuracy on utility operation and production costs. Wind speed data from San Gorgonio Pass, California during 1979 are used to estimate wind turbine performance using four different simulation methods. (LEW)

Goldenblatt, M.K.; Wegley, H.L.; Miller, A.H.

1983-03-01T23:59:59.000Z

385

Wind Regimes in Complex Terrain of the Great Valley of Eastern Tennessee  

SciTech Connect (OSTI)

This research was designed to provide an understanding of physical wind mechanisms within the complex terrain of the Great Valley of Eastern Tennessee to assess the impacts of regional air flow with regard to synoptic and mesoscale weather changes, wind direction shifts, and air quality. Meteorological data from 2008 2009 were analyzed from 13 meteorological sites along with associated upper level data. Up to 15 ancillary sites were used for reference. Two-step complete linkage and K-means cluster analyses, synoptic weather studies, and ambient meteorological comparisons were performed to generate hourly wind classifications. These wind regimes revealed seasonal variations of underlying physical wind mechanisms (forced channeled, vertically coupled, pressure-driven, and thermally-driven winds). Synoptic and ambient meteorological analysis (mixing depth, pressure gradient, pressure gradient ratio, atmospheric and surface stability) suggested up to 93% accuracy for the clustered results. Probabilistic prediction schemes of wind flow and wind class change were developed through characterization of flow change data and wind class succession. Data analysis revealed that wind flow in the Great Valley was dominated by forced channeled winds (45 67%) and vertically coupled flow (22 38%). Down-valley pressure-driven and thermally-driven winds also played significant roles (0 17% and 2 20%, respectively), usually accompanied by convergent wind patterns (15 20%) and large wind direction shifts, especially in the Central/Upper Great Valley. The behavior of most wind regimes was associated with detectable pressure differences between the Lower and Upper Great Valley. Mixing depth and synoptic pressure gradients were significant contributors to wind pattern behavior. Up to 15 wind classes and 10 sub-classes were identified in the Central Great Valley with 67 joined classes for the Great Valley at-large. Two-thirds of Great Valley at-large flow was defined by 12 classes. Winds flowed on-axis only 40% of the time. The Great Smoky Mountains helped create down-valley pressure-driven winds, downslope mountain breezes, and divergent air flow. The Cumberland Mountains and Plateau were associated with wind speed reductions in the Central Great Valley, Emory Gap Flow, weak thermally-driven winds, and northwesterly down sloping. Ridge-and-valley terrain enhanced wind direction reversals, pressure-driven winds, as well as locally and regionally produced thermally-driven flow.

Birdwell, Kevin R [ORNL

2011-05-01T23:59:59.000Z

386

Global ocean wind power sensitivity to surface layer stability  

E-Print Network [OSTI]

observa- tions, vertical wind speed profile estimation givenspeed differences compared to over the Gulf Stream, 80 m wind power is relatively smaller because of reduced verticalvertical momentum transfer over the Gulf Stream and North Atlantic Current results in sub-logarithmic wind profiles, reduced 80 – 10 m wind speed

Capps, Scott B; Zender, Charles S

2009-01-01T23:59:59.000Z

387

Influence of wind characteristics on turbine performance Ioannis Antoniou (1)  

E-Print Network [OSTI]

(2) , Peder Enevoldsen (2) , Leo Thesbjerg (3) (1): Wind Energy Department, Risø of measuring the power curve is by using the wind speed at hub height. The assumption behind this is that the wind speed is representative of the wind over the whole turbine rotor. While this assumption

388

Use of synthetic aperture radar for offshore wind resource assessment and wind farm development in the UK   

E-Print Network [OSTI]

The UK has an abundant offshore wind resource with offshore wind farming set to grow rapidly over the coming years. Optimisation of energy production is of the utmost importance and accurate estimates of wind speed distributions are critical...

Cameron, Iain Dickson

2008-01-01T23:59:59.000Z

389

Wind energy  

Science Journals Connector (OSTI)

Wind energy is rapidly growing. In 2006 the installed generating capacity in the world increased by 25%, a growth rate which has more or less been sustained during the last decade. And there is no reason to believe that this growth will slow significantly in the coming years. For example, the United Kingdom's goal for installed wind turbines by 2020 is 33 GW up from 2 GW in 2006, an average annual growth rate of 22% over that period. More than half of all turbines are installed in Europe, but United States, India and lately China are also rapidly growing markets. The cradle of modern wind energy was set by innovative blacksmiths in rural Denmark. Now the wind provides more than 20% of the electrical power in Denmark, the industry has professionalized and has close ties with public research at universities. This focus issue is concerned with research in wind energy. The main purposes of research in wind energy are to: decrease the cost of power generated by the wind; increase the reliability and predictability of the energy source; investigate and reduce the adverse environmental impact of massive deployment of wind turbines; build research based educations for wind energy engineers. This focus issue contains contributions from several fields of research. Decreased costs cover a very wide range of activities from aerodynamics of the wind turbine blades, optimal site selection for the turbines, optimization of the electrical grid and power market for a fluctuating source, more efficient electrical generators and gears, and new materials and production techniques for turbine manufacturing. The United Kingdom recently started the construction of the London Array, a 1 GW off-shore wind farm east of London consisting of several hundred turbines. To design such a farm optimally it is necessary to understand the chaotic and very turbulent flow downwind from a turbine, which decreases the power production and increases the mechanical loads on other nearby turbines. Also addressed within the issue is how much conventional power production can be replaced by the ceaseless wind, with the question of how Greece's target of 29% renewables by 2020 is to be met efficiently. Other topics include an innovative way to determine the power curve of a turbine experimentally more accurately, the use of fluid dynamics tools to investigate the implications of placing vortex generators on wind turbine blades (thereby possibly improving their efficiency) and a study of the perception of wind turbine noise. It turns out that a small but significant fraction of wind turbine neighbours feel that turbine generated noise impairs their ability to rest. The annoyance is correlated with a negative attitude towards the visual impact on the landscape, but what is cause and effect is too early to say. As mentioned there is a rush for wind turbines in many countries. However, this positive development for the global climate is currently limited by practical barriers. One bottleneck is the difficulties for the sub-suppliers of gears and other parts to meet the demand. Another is the difficulties to meet the demand for engineers specialized in wind. For that reason the Technical University of Denmark (DTU) recently launched the world's first Wind Energy Masters Program. Here and elsewhere in the world of wind education and research we should really speed up now, as our chances of contributing to emission free energy production and a healthier global climate have never been better. Focus on Wind Energy Contents The articles below represent the first accepted contributions and further additions will appear in the near future. Wind turbines—low level noise sources interfering with restoration? Eja Pedersen and Kerstin Persson Waye On the effect of spatial dispersion of wind power plants on the wind energy capacity credit in Greece George Caralis, Yiannis Perivolaris, Konstantinos Rados and Arthouros Zervos Large-eddy simulation of spectral coherence in a wind turbine wake A Jimenez, A Crespo, E Migoya and J Garcia How to improve the estimation of

Jakob Mann; Jens Nřrkćr Sřrensen; Poul-Erik Morthorst

2008-01-01T23:59:59.000Z

390

Optimal Siting of Offshore Wind Farms  

Science Journals Connector (OSTI)

The goal of this study is finding the best location for constructing an offshore wind farm with respect to investment and operation costs and technical limitations. Wind speed, sea depth and distance between shor...

Salman Kheirabadi Shahvali…

2014-01-01T23:59:59.000Z

391

Floating offshore wind farms : demand planning & logistical challenges of electricity generation  

E-Print Network [OSTI]

Floating offshore wind farms are likely to become the next paradigm in electricity generation from wind energy mainly because of the near constant high wind speeds in an offshore environment as opposed to the erratic wind ...

Nnadili, Christopher Dozie, 1978-

2009-01-01T23:59:59.000Z

392

The effects of energy storage properties and forecast accuracy on mitigating variability in wind power generation  

E-Print Network [OSTI]

Electricity generation from wind power is increasing worldwide. Wind power can offset traditional fossil fuel generators which is beneficial to the environment. However, wind generation is unpredictable. Wind speeds have ...

Jaworsky, Christina A

2013-01-01T23:59:59.000Z

393

Near-surface meteorological conditions associated with active resuspension of dust by wind erosion  

SciTech Connect (OSTI)

The meteorological conditions associated with extreme winds in the lee of the Colorado Rocky Mountains were studied from the viewpoint of dust resuspension and dispersion. Wind, dispersion, temperature, and dew point conditions occurring near the surface were discussed in detail for a selected event. Near-surface wind speeds were compared to observations made at a standard sampling height. These field data were developed to aid in validation and interpretation of wind tunnel observations and application of dispersion models to wind erosion resuspension. Three conclusions can immediately be drawn from this investigation. First, wind storms in nature are quite gusty, with gusts exceeding the mean speed by 50 percent or more. However, wind direction variations are small by comparison. Thus, wind tunnel studies should be able to simulate the large along-flow turbulence, while keeping cross-flow turbulence to a moderate level. This also has an application to the puff modeling of high winds. Puff models normally assume that the along-flow dispersion coefficient is equal to the cross-flow value. This study suggests that the along-flow coefficient should be much larger than its cross-flow counterpart. Another conclusion involves the usual assumption of Pasquill-Gifford stability class D. In the event studied here, the atmosphere was well mixed with near-neutral thermal stability, yet the horizontal dispersion stability class varied from G to A. Thus, an assumption of Class D horizontal dispersion during high winds would not have been valid during this case. A final conclusion involves the widely applied assumption of a logarithmic wind speed profile during high wind events. This study has indicated that such an assumption is appropriate.

Hodgin, C.R.

1982-01-01T23:59:59.000Z

394

Low-frequency wind noise correlation in microphone arrays  

Science Journals Connector (OSTI)

A three-axis orthogonal microphone array with ten sensors in each arm has been used to study wind noise in the frequency range from 0.05 to 50 Hz. Simultaneous measurements were made of the three components of the varying wind velocity.Measurements have been made for wind speeds from 4 to 7 m/s at three different sites. The frequency-dependent correlation of the wind noise over a range of wind velocities and atmospheric and environmental conditions in the downwind direction varies as exp (?3.2X) cos (2?X). For the crosswind and vertical directions the correlation decays approximately as exp (?7Y) where X is the separation in wavelengths in the downwind direction and Y is this separation in the crosswind or vertical direction. Over a limited range of wave numbers the power density spectra of the varying wind velocity varied as the wave number to the ? 5 3 power and the pressure spectra as the ? 7 3 power.

F. Douglas Shields

2005-01-01T23:59:59.000Z

395

Saturation wind power potential and its implications for wind energy  

Science Journals Connector (OSTI)

...and natural gas produce electricity...As such, wind turbines reduce direct...power, part I: Technologies, energy resources...arrays of wind turbines . J Wind Eng Ind...Yamada T (1982) Development of a turbulence...biofuel soot and gases, and methane...a single wind turbine intersects...

Mark Z. Jacobson; Cristina L. Archer

2012-01-01T23:59:59.000Z

396

Influence of Thermal Stratification on Wind Profiles for Heights up to 140 m  

E-Print Network [OSTI]

.energiemeteorologie.de The vertical wind speed profile has to be know for many wind power applications. Although the large effect speeds are not measured or predicted in the hubheight of the wind turbine. For the vertical trans stratification of the boundary layer has also an important influence on the vertical wind speed profile. Only

Heinemann, Detlev

397

Measured wind turbine loads and their dependence on inflow parameters L. Manuel & L. D. Nelson  

E-Print Network [OSTI]

of the hub-height horizontal wind speed as well as secondary pa- rameters such as Reynolds stresses, vertical to other previous studies, but we do not bin the data sets by wind speed since dependen- cies in one wind turbine loads. Inflow parameters might include, for example, mean wind speed, turbu- lence intensity

Manuel, Lance

398

Research on Control System of High Power DFIG Wind Power System  

Science Journals Connector (OSTI)

Compared with constant speed constant frequency wind turbine, variable speed constant frequency wind turbine has many advantages: higher efficiency of wind energy converting to electric power, absorbing gust energy, smoothly cutting into the network ... Keywords: wind power, DFIG, high power, LQR, variable speed constant frequency, constant power control

Li Jianlin; Xu Honghua

2008-12-01T23:59:59.000Z

399

Sensitivity of the wind stress and storm surges to surface drag  

E-Print Network [OSTI]

- 29 April 2009 , CD zU ln~ #12;Background Air-Sea Interaction High and/or extreme wind speeds , CD ? #12;Background Air-Sea Interaction High and/or extreme wind speeds ­ Dynamics Sensitivity High and/or extreme wind speeds ­ Dynamics Sensitivity of the wind stress and storm surges to surface

Vries, Hans de

400

Operating wind turbines in strong wind conditions by using feedforward-feedback control  

Science Journals Connector (OSTI)

Due to the increasing penetration of wind energy into power systems, it becomes critical to reduce the impact of wind energy on the stability and reliability of the overall power system. In precedent works, Shen and his co-workers developed a re-designed operation schema to run wind turbines in strong wind conditions based on optimization method and standard PI feedback control, which can prevent the typical shutdowns of wind turbines when reaching the cut-out wind speed. In this paper, a new control strategy combing the standard PI feedback control with feedforward controls using the optimization results is investigated for the operation of variable-speed pitch-regulated wind turbines in strong wind conditions. It is shown that the developed control strategy is capable of smoothening the power output of wind turbine and avoiding its sudden showdown at high wind speeds without worsening the loads on rotor and blades.

Ju Feng; Wen Zhong Sheng

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Power Electronic Control for Wind Generation Systems  

Science Journals Connector (OSTI)

...? mathematical models for wind turbines such as wind turbine (WT) with doubly fed induction generator (DFIG) and WT with direct-drive permanent magnet...

Xiao-Ping Zhang; Christian Rehtanz…

2012-01-01T23:59:59.000Z

402

Measured speed versus true speed  

E-Print Network [OSTI]

The theoretical predictions, derived from the Lorentz and the Tangherlini transformations, for the one-way speed of any physical entity are confronted with the corresponding expressions for the one-way measured speed obtained from a gedanken experiment. The experiment demonstrates that, for an inertial frame $K'$ in motion relative to an inertial frame $K$ where the one-way speed of light is isotropic, even the special theory of relativity renders the one-way speed of light as function of the velocity of $K'$ in agreement with the Tangherlini transformations. However, the two-way speed of light remains constant for all inertial frames, in agreement with the two-way experimental techniques. This implies that there must exist \\emph{one and only one} inertial frame where the one-way speed of light is isotropic. These investigations also show how we can determine, with certain restrictions, the true speed of a physical entity and of the true speed of $K'$ relative to $K$.

Israel Perez

2010-05-10T23:59:59.000Z

403

Uncovering wind turbine properties through two-dimensional stochastic modeling of wind dynamics  

E-Print Network [OSTI]

Using a method for stochastic data analysis, borrowed from statistical physics, we analyze synthetic data from a Markov chain model that reproduces measurements of wind speed and power production in a wind park in Portugal. From the theoretical point of view we argue that our methods can be used to extract unknown functional relations between two variables. We first show that indeed our analysis retrieves the power performance curve, which yields the relationship between wind speed and power production and discuss how such procedure can be extended for extracting functional relationships between pairs of physical variables in general. Second, we show how specific features, such as the turbine rated wind speed or the descriptive wind speed statistics, can be related with the equations describing the evolution of power production and wind speed at single wind turbines.

Raischel, Frank; Lopes, Vitor V; Lind, Pedro G

2012-01-01T23:59:59.000Z

404

Environmental impact of wind energy  

Science Journals Connector (OSTI)

One purpose of wind turbines is to provide pollution-free electric power at a reasonable price in an environmentally sound way. In this focus issue the latest research on the environmental impact of wind farms is presented. Offshore wind farms affect the marine fauna in both positive and negative ways. For example, some farms are safe havens for porpoises while other farms show fewer harbor porpoises even after ten years. Atmospheric computer experiments are carried out to investigate the possible impact and resource of future massive installations of wind turbines. The following questions are treated. What is the global capacity for energy production by the wind? Will the added turbulence and reduced wind speeds generated by massive wind farms cool or heat the surface? Can wind farms affect precipitation? It is also shown through life-cycle analysis how wind energy can reduce the atmospheric emission of eight air pollutants. Finally, noise generation and its impact on humans are studied.

J Mann; J Teilmann

2013-01-01T23:59:59.000Z

405

A bio-inspired approach to enhancing wind power conversion  

Science Journals Connector (OSTI)

The primary objective of this investigation is to develop a new control method for wind turbines that can increase their wind energy capture efficiency. Since the resultant wind turbinesystemdynamics are profoundly nonlinear and coupled with significant uncertainties traditional model-based control is found to be not only structurally complex but also computationally expensive. Here we explore two sets of control algorithms to enhance wind to electrical energy conversion. The first accounts for system nonlinearities and external disturbances by integrating variable structure control with adaptive control. The second accommodates the nonlinearities arising from rotor aerodynamics and pitch (actuation) dynamics as well as external disturbances through a method inspired by a 1st order human memory/learning model. The second method allows direct maximum power coefficient tracking for winds under the rated speed and ensures rated power output for winds over the rated speed. Basically it uses the system current and most recent memorized responses together with past control experience to generate new control actions. Both rotor dynamics and actuation (pitch) dynamics are reflected indirectly through the observed/measured system response at each instant and are embedded within the control mechanism. Thus there is no need for detailed information on the system model or system parameters in the control’s design and implementation. The efficacy of both proposed approaches is analyzed through numerical simulations.

YongDuan Song; WenChuan Cai; Peng Li; YongSheng Hu

2012-01-01T23:59:59.000Z

406

Analysis and forecasting of wind velocity in chetumal, quintana roo, using the single exponential smoothing method  

Science Journals Connector (OSTI)

In this paper the analysis and forecasting of wind velocities in Chetumal, Quintana Roo, Mexico is presented. Measurements were made by the Instituto de Investigaciones Eléctricas (IIE) during two years, from 2004 to 2005. This location exemplifies the wind energy generation potential in the Caribbean coast of Mexico that could be employed in the hotel industry in the next decade. The wind speed and wind direction were measured at 10 m above ground level. Sensors with high accuracy and a low starting threshold were used. The wind velocity was recorded using a data acquisition system supplied by a 10 W photovoltaic panel. The wind speed values were measured with a frequency of 1 Hz and the average wind speed was recorded considering regular intervals of 10 min. First a statistical analysis of the time series was made in the first part of the paper through conventional and robust measures. Also the forecasting of the last day of measurements was made utilizing the single exponential smoothing method (SES). The results showed a very good accuracy of the data with this technique for an ? value of 0.9. Finally the SES method was compared with the artificial neural network (ANN) method showing the former better results.

E. Cadenas; O.A. Jaramillo; W. Rivera

2010-01-01T23:59:59.000Z

407

Evaluation of global wind power Cristina L. Archer and Mark Z. Jacobson  

E-Print Network [OSTI]

Evaluation of global wind power Cristina L. Archer and Mark Z. Jacobson Department of Civil the world's wind power potential for the first time from data. Wind speeds are calculated at 80 m, the hub% of all reporting stations experience annual mean wind speeds ! 6.9 m/s at 80 m (i.e., wind power class 3

408

Is the Weibull distribution really suited for wind statistics modeling and wind power evaluation?  

E-Print Network [OSTI]

Wind speed statistics is generally modeled using the Weibull distribution. This distribution is convenient since it fully characterizes analytically with only two parameters (the shape and scale parameters) the shape of distribution and the different moments of the wind speed (mean, standard deviation, skewness and kurtosis). This distribution is broadly used in the wind energy sector to produce maps of wind energy potential. However, the Weibull distribution is based on empirical rather than physical justification and might display strong limitations for its applications. The philosophy of this article is based on the modeling of the wind components instead of the wind speed itself. This provides more physical insights on the validity domain of the Weibull distribution as a possible relevant model for wind statistics and the quantification of the error made by using such a distribution. We thereby propose alternative expressions of more suited wind speed distribution.

Drobinski, Philippe

2012-01-01T23:59:59.000Z

409

PSO (FU 2101) Ensemble-forecasts for wind power  

E-Print Network [OSTI]

PSO (FU 2101) Ensemble-forecasts for wind power Wind Power Ensemble Forecasting Using Wind Speed the problems of (i) transforming the meteorological ensembles to wind power ensembles and, (ii) correcting) data. However, quite often the actual wind power production is outside the range of ensemble forecast

410

Wind Farm Power Prediction: A Data-Mining Approach  

E-Print Network [OSTI]

into a wind power plant. A number of different approaches have been used in forecasting wind speed and windWind Farm Power Prediction: A Data-Mining Approach Andrew Kusiak*, Haiyang Zheng and Zhe Song, IA 52242­1527, USA In this paper, models for short- and long-term prediction of wind farm power

Kusiak, Andrew

411

Ris-R-1111(EN) Ultimate Loading of Wind Turbines  

E-Print Network [OSTI]

-R-1111(EN) 2 Abstract An extreme loading study has been conducted comprising a general wind climate the environmental wind climate. With the trend of persistently growing turbines, the extreme loading seems to become, and extreme wind events. Examples of extreme wind events are extreme mean wind speeds with a recurrence period

412

Optimum propeller wind turbines  

SciTech Connect (OSTI)

The Prandtl-Betz-Theodorsen theory of heavily loaded airscrews has been adapted to the design of propeller windmills which are to be optimized for maximum power coefficient. It is shown that the simpler, light-loading, constant-area wake assumption can generate significantly different ''optimum'' performance and geometry, and that it is therefore not appropriate to the design of propeller wind turbines when operating in their normal range of high-tip-speed-to-wind-speed ratio. Design curves for optimum power coefficient are presented and an example of the design of a typical two-blade optimum rotor is given.

Sanderson, R.J.; Archer, R.D.

1983-11-01T23:59:59.000Z

413

E-Print Network 3.0 - aggregated wind power Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

and the increased wind power penetration in power systems the main trend for modern wind turbines is clearly... variable speed operation and grid connection via ... Source: Ris...

414

NREL GIS Data: Global Offshore Wind - Datasets - OpenEI Datasets  

Open Energy Info (EERE)

NREL GIS Data: Global ... Dataset Activity Stream NREL GIS Data: Global Offshore Wind GIS data for offshore wind speed (meterssecond). Specified to Exclusive Economic Zones (EEZ)....

415

The effect of high penetration of wind power on primary frequency control of power systems.  

E-Print Network [OSTI]

??In this work, a power system with wind power units and hydro power units are considered. The hydro power unit and variable speed wind turbine… (more)

Motamed, Bardia

2013-01-01T23:59:59.000Z

416

Quantifying the system balancing cost when wind energy is incorporated into electricity generation system.  

E-Print Network [OSTI]

??Incorporation of wind energy into the electricity generation system requires a detailed analysis of wind speed in order to minimize system balancing cost and avoid… (more)

Issaeva, Natalia

2009-01-01T23:59:59.000Z

417

Revisiting an Old Concept: The Gradient Wind  

Science Journals Connector (OSTI)

The gradient wind is defined as a horizontal wind having the same direction as the geostrophic wind but with a magnitude consistent with a balance of three forces: the pressure gradient force, the Coriolis force, and the centrifugal force arising ...

Keith F. Brill

2014-04-01T23:59:59.000Z

418

Microphysical Structure of the Marine Boundary Layer under Strong Wind and Spray Formation as Seen from Simulations Using a 2D Explicit  

E-Print Network [OSTI]

in the vertical profiles of wind speed occurring with in- creasing wind speeds were attributed to a decrease generation is de- termined by a source function depending on the background wind speed assumed in the surface roughness and the drag coefficient for wind speeds exceeding about 33 m s21 . This decrease

Mark, Pinsky

419

Active control system for high speed windmills  

DOE Patents [OSTI]

A pump stroke is matched to the operating speed of a high speed windmill. The windmill drives a hydraulic pump for a control. Changes in speed of a wind driven shaft open supply and exhaust valves to opposite ends of a hydraulic actuator to lengthen and shorten an oscillating arm thereby lengthening and shortening the stroke of an output pump. Diminishing wind to a stall speed causes the valves to operate the hydraulic cylinder to shorten the oscillating arm to zero. A pressure accumulator in the hydraulic system provides the force necessary to supply the hydraulic fluid under pressure to drive the actuator into and out of the zero position in response to the windmill shaft speed approaching and exceeding windmill stall speed. 4 figs.

Avery, D.E.

1988-01-12T23:59:59.000Z

420

New England Wind Forum: Markets  

Wind Powering America (EERE)

Markets Markets Selling Wind Power Wind generators interconnected directly to the transmission or distribution grid, or sized in excess of the load of a host end-user, interact with either well-developed or developing markets for the products produced by wind generators: electricity and generation attributes. Buying Wind Power Individuals, companies, institutions, and governments throughout New England have a number of opportunities to buying wind power or support the development of wind power. The links below take you to information on opportunities and guidance for buying wind power in New England. Motivations for Buying Wind Power Buying Wind Power Resources and Tools for Large Energy Users Printable Version Skip footer navigation to end of page. New England Wind Forum Home | Wind Program Home | EERE Home | U.S. Department of Energy

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Wind derivatives: hedging wind risk:.  

E-Print Network [OSTI]

??Wind derivatives are financial contracts that can be used to hedge or mitigate wind risk. In this thesis, the focus was on pricing these wind… (more)

Hoyer, S.A.

2013-01-01T23:59:59.000Z

422

Solar Wind Forecasting with Coronal Holes  

E-Print Network [OSTI]

An empirical model for forecasting solar wind speed related geomagnetic events is presented here. The model is based on the estimated location and size of solar coronal holes. This method differs from models that are based on photospheric magnetograms (e.g., Wang-Sheeley model) to estimate the open field line configuration. Rather than requiring the use of a full magnetic synoptic map, the method presented here can be used to forecast solar wind velocities and magnetic polarity from a single coronal hole image, along with a single magnetic full-disk image. The coronal hole parameters used in this study are estimated with Kitt Peak Vacuum Telescope He I 1083 nm spectrograms and photospheric magnetograms. Solar wind and coronal hole data for the period between May 1992 and September 2003 are investigated. The new model is found to be accurate to within 10% of observed solar wind measurements for its best one-month periods, and it has a linear correlation coefficient of ~0.38 for the full 11 years studied. Using a single estimated coronal hole map, the model can forecast the Earth directed solar wind velocity up to 8.5 days in advance. In addition, this method can be used with any source of coronal hole area and location data.

S. Robbins; C. J. Henney; J. W. Harvey

2007-01-09T23:59:59.000Z

423

Characteristics of 50–200-m Winds and Temperatures Derived from an Iowa Tall-Tower Network  

Science Journals Connector (OSTI)

Limitations in skill of wind speed forecasts lead to conservative bids of wind-plant production in the day-ahead energy market and usually to an underutilization of wind resources. Improvements are needed in understanding wind characteristics in ...

Renee A. Walton; Eugene S. Takle; William A. Gallus Jr.

2014-10-01T23:59:59.000Z

424

Numeric-modeling sensitivity analysis of the performance of wind turbine arrays  

SciTech Connect (OSTI)

An evaluation of the numerical model created by Lissaman for predicting the performance of wind turbine arrays has been made. Model predictions of the wake parameters have been compared with both full-scale and wind tunnel measurements. Only limited, full-scale data were available, while wind tunnel studies showed difficulties in representing real meteorological conditions. Nevertheless, several modifications and additions have been made to the model using both theoretical and empirical techniques and the new model shows good correlation with experiment. The larger wake growth rate and shorter near wake length predicted by the new model lead to reduced interference effects on downstream turbines and hence greater array efficiencies. The array model has also been re-examined and now incorporates the ability to show the effects of real meteorological conditions such as variations in wind speed and unsteady winds. The resulting computer code has been run to show the sensitivity of array performance to meteorological, machine, and array parameters. Ambient turbulence and windwise spacing are shown to dominate, while hub height ratio is seen to be relatively unimportant. Finally, a detailed analysis of the Goodnoe Hills wind farm in Washington has been made to show how power output can be expected to vary with ambient turbulence, wind speed, and wind direction.

Lissaman, P.B.S.; Gyatt, G.W.; Zalay, A.D.

1982-06-01T23:59:59.000Z

425

Can Wind Lidars Measure Turbulence?  

Science Journals Connector (OSTI)

Modeling of the systematic errors in the second-order moments of wind speeds measured by continuous-wave (ZephIR) and pulsed (WindCube) lidars is presented. These lidars use the conical scanning technique to measure the velocity field. The model ...

A. Sathe; J. Mann; J. Gottschall; M. S. Courtney

2011-07-01T23:59:59.000Z

426

A Study on Vibration Isolation in a Wind Turbine Subjected to Wind and Seismic Loading.  

E-Print Network [OSTI]

??The primary loading on wind turbines is in the lateral direction and is of a stochastic nature, due to wind and seismic forces. As turbines… (more)

Van der Woude, Chad

2011-01-01T23:59:59.000Z

427

Small wind turbine emulator with armature controlled separately excited DC motor via analogue electronic circuit  

Science Journals Connector (OSTI)

In this paper, a small wind turbine emulator (WTE) using separately excited DC motor is modelled, designed, simulated, implemented and tested. A 1 HP separately excited DC motor is used to emulate the characteristics of the rotor of small wind turbine. The DC motor is driven by a thyristor bridge with closed-loop cascaded PI controller for armature control. A separately excited DC generator with a variable resistive load is directly coupled to the DC motor. A small cheap analogue electronic circuit, with less interfacing, is used to generate a specific reference wind turbine speed based on the wind turbine rotor characteristics and the mechanical wind power available. Simulation and experimental results are compared to proof the validity and accuracy of the WTE.

A. Mahdy; S.M. El-Hakim; Hanafy Hassan Hanafy

2012-01-01T23:59:59.000Z

428

Distribution of Extreme Winds in the Bonneville Power Administration Service Area  

Science Journals Connector (OSTI)

Annual extreme 1 min wind speeds at 78 Pacific Northwest locations were analyzed using the Fisher-Tippet type II extreme value function. From computed mean recurrence intervals, we could easily determine the wind speed likely to recur in a ...

J. William Wantz; Robert E. Sinclair

1981-12-01T23:59:59.000Z

429

Market penetration of wind turbine concepts over the years Anca D. Hansen1  

E-Print Network [OSTI]

speed wind turbine concept with partial-scale power converter (DFIG) This configuration denotes the variable speed controlled wind turbine with doubly fed induction generator (DFIG) and pitch control

430

Investigation of Flow, Turbulence, and Dispersion within Built Environments  

E-Print Network [OSTI]

fluctuation and vertical mean wind speed reduced finefluctuation ( ? w ) and vertical mean wind speed (W) on DTFPwind speed; W -vertical mean wind speed; WD -wind direction;

Pan, Hansheng

2011-01-01T23:59:59.000Z

431

Wind Structure in the Atmospheric Boundary Layer  

Science Journals Connector (OSTI)

13 May 1971 research-article Wind Structure in the Atmospheric Boundary Layer...semi-empirical laws for the variation of mean wind speed with height and for the statistical...provide some useful ordering of the mean wind profile characteristics in relation to...

1971-01-01T23:59:59.000Z

432

Offshore wind resource assessment through satellite images  

E-Print Network [OSTI]

1 Slide no. 4 Offshore wind resource assessment through satellite images Charlotte Bay Hasager images for offshore wind ressource assessment in lieu of in-situ mast observations #12;4 Slide no Hasager, Dellwik, Nielsen and Furevik, 2004, Validation of ERS-2 SAR offshore wind-speed maps in the North

433

Offshore Wind Turbine Wakes Measured by Sodar  

Science Journals Connector (OSTI)

A ship-mounted sodar was used to measure wind turbine wakes in an offshore wind farm in Denmark. The wake magnitude and vertical extent were determined by measuring the wind speed profile behind an operating turbine, then shutting down the ...

R. J. Barthelmie; L. Folkerts; F. T. Ormel; P. Sanderhoff; P. J. Eecen; O. Stobbe; N. M. Nielsen

2003-04-01T23:59:59.000Z

434

Wind Speed Scaling in Fully Developed Seas  

Science Journals Connector (OSTI)

Recent tests of all generations of numerical wave models indicate that extreme wave heights are significantly underpredicted by these models. This behavior is consistent with the finding by Ewing and Laing that fully developed wave spectra do not ...

Donald T. Resio; Val R. Swail; Robert E. Jensen; Vincent J. Cardone

1999-08-01T23:59:59.000Z

435

Final Statewide Wind Maps and Modifications Report N e v a d aN e v a d a  

E-Print Network [OSTI]

4500000 4500000 4750000 4750000 Mean Annual Wind Speed of California at 30 MetersMean Annual Wind Speed 4500000 4500000 4750000 4750000 Mean Annual Wind Speed of California at 50 MetersMean Annual Wind SpeedV Final Statewide Wind Maps and Modifications Report #12;N e v a d aN e v a d a O r e g o nO r e g

436

Abstract--Wind power generation is growing rapidly. However, maintaining the wind turbine connection to grid is a real  

E-Print Network [OSTI]

1 Abstract--Wind power generation is growing rapidly. However, maintaining the wind turbine and the generator design. The fixed-speed wind turbine has the advantage of the low cost of A. F. Abdou and H. R advantages over the fixed-speed operation, such as maximum power capture, less mechanical stresses, and less

Pota, Himanshu Roy

437

Mesoscale Simulations of a Wind Ramping Event for Wind Energy Prediction  

SciTech Connect (OSTI)

Ramping events, or rapid changes of wind speed and wind direction over a short period of time, present challenges to power grid operators in regions with significant penetrations of wind energy in the power grid portfolio. Improved predictions of wind power availability require adequate predictions of the timing of ramping events. For the ramping event investigated here, the Weather Research and Forecasting (WRF) model was run at three horizontal resolutions in 'mesoscale' mode: 8100m, 2700m, and 900m. Two Planetary Boundary Layer (PBL) schemes, the Yonsei University (YSU) and Mellor-Yamada-Janjic (MYJ) schemes, were run at each resolution as well. Simulations were not 'tuned' with nuanced choices of vertical resolution or tuning parameters so that these simulations may be considered 'out-of-the-box' tests of a numerical weather prediction code. Simulations are compared with sodar observations during a wind ramping event at a 'West Coast North America' wind farm. Despite differences in the boundary-layer schemes, no significant differences were observed in the abilities of the schemes to capture the timing of the ramping event. As collaborators have identified, the boundary conditions of these simulations probably dominate the physics of the simulations. They suggest that future investigations into characterization of ramping events employ ensembles of simulations, and that the ensembles include variations of boundary conditions. Furthermore, the failure of these simulations to capture not only the timing of the ramping event but the shape of the wind profile during the ramping event (regardless of its timing) indicates that the set-up and execution of such simulations for wind power forecasting requires skill and tuning of the simulations for a specific site.

Rhodes, M; Lundquist, J K

2011-09-21T23:59:59.000Z

438

Wind power generating system  

SciTech Connect (OSTI)

Normally feathered propeller blades of a wind power generating system unfeather in response to the actuation of a power cylinder that responds to actuating signals. Once operational, the propellers generate power over a large range of wind velocities. A maximum power generation design point signals a feather response of the propellers so that once the design point is reached no increase in power results, but the system still generates power. At wind speeds below this maximum point, propeller speed and power output optimize to preset values. The propellers drive a positive displacement pump that in turn drives a positive displacement motor of the swash plate type. The displacement of the motor varies depending on the load on the system, with increasing displacement resulting in increasing propeller speeds, and the converse. In the event of dangerous but not clandestine problems developing in the system, a control circuit dumps hydraulic pressure from the unfeathering cylinder resulting in a predetermined, lower operating pressure produced by the pump. In the event that a problem of potentially cladestine consequence arises, the propeller unfeathering cylinder immediately unloads. Upon startup, a bypass around the motor is blocked, applying a pressure across the motor. The motor drives the generator until the generator reaches a predetermined speed whereupon the generator is placed in circuit with a utility grid and permitted to motor up to synchronous speed.

Schachle, Ch.; Schachle, E. C.; Schachle, J. R.; Schachle, P. J.

1985-03-12T23:59:59.000Z

439

Stakeholder Engagement and Outreach: Where Is Wind Power?  

Wind Powering America (EERE)

Where Is Wind Power? Where Is Wind Power? Wind Powering America offers maps to help you visualize the wind resource at a local level and to show how much wind power has been installed in the United States. How much wind power is on my land? Go to the wind resource maps. Go to the wind resource maps. Go to the wind resource maps. If you want to know how much wind power is in a particular area, these wind resource maps can give you a visual indication of the average wind speeds to a local level such as a neighborhood. These maps have been developed using the same mathematical models that are used by weather forecasters and are even used to estimate the wind energy potential-or how much wind energy could potentially be produced at the state level, if wind power were developed there.

440

New England Wind Forum: Determining Factors Influencing Wind Economics in  

Wind Powering America (EERE)

Determining Factors Influencing Wind Economics in New England Determining Factors Influencing Wind Economics in New England Figure 1: Installed Wind Project Costs by Region: 2003 through 2006 Projects Only New England's high land values, smaller land parcels, varied terrain, and more moderate wind speeds make for projects of smaller scale and higher unit cost than those likely to be built in Texas or the Great Plains states. Click on the graph to view a larger version. New England's high land values, smaller land parcels, varied terrain, and more moderate wind speeds make for projects of smaller scale and higher unit cost than those likely to be built in Texas or the Great Plains states. View a larger version of the graph. Figure 2: 2006 Project Capacity Factors by Region: 2002 through 2005 Projects Only The chart depicts project capacity factor by region. Click on the graph to view a larger version.

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Confronting the winds: orientation and flight behaviour of roosting swifts, Apus apus  

Science Journals Connector (OSTI)

...expected to match the wind speed up to the maximum speed that their power capacity allows...stationary ight into the wind at speed W, under...conditions of a convex power func- tion P(V...carried away by the wind. 3. METHODS We used...X-band, 200kW peak power, 0.25ms pulse duration...

2001-01-01T23:59:59.000Z

442

Wind modelling based on wind input data conditions using Weibull distribution  

Science Journals Connector (OSTI)

Weibull distribution can be used to model the wind speed distribution at a particular site and hence, it can help in wind resource assessment (WRA) of a site. By calculating the shape (k) and scale (c) parameters for Weibull distribution, the wind speed frequency curve for a site can be made. Once this wind speed distribution for site is determined, it can be convolved with the power curve for a wind turbine and the annual energy output from the site can be determined. This paper presents how the Weibull distribution is used to determine the wind speed distribution for Vadravadra site in Gau Island of Fiji and how closely the annual energy output from the modelled wind speed distribution matches with the annual energy output using the actual wind speed distribution. It also presents how k is related to the turbulence intensity for a site; how the c is related to the annual mean wind speed and how a formula for estimating c is derived at a new height.

R.D. Prasad; R.C. Bansal; M. Sauturaga

2009-01-01T23:59:59.000Z

443

Coastal Ohio Wind Project for Reduced Barriers to Deployment of Offshore Wind Energy  

SciTech Connect (OSTI)

The Coastal Ohio Wind Project was created to establish the viability of wind turbines on the coastal and offshore regions of Northern Ohio. The project’s main goal was to improve operational unit strategies used for environmental impact assessment of offshore turbines on lake wildlife by optimizing and fusing data from the multi-instrument surveillance system and providing an engineering analysis of potential design/operational alternatives for offshore wind turbines. The project also developed a general economic model for offshore WTG deployment to quantify potential revenue losses due to wind turbine shutdown related to ice and avian issues. In a previous phase of this project (Award Number: DE-FG36-06GO86096), we developed a surveillance system that was used to collect different parameters such as passage rates, flight paths, flight directions, and flight altitudes of nocturnal migrating species, movements of birds and bats, and bird calls for assessing patterns and peak passage rates during migration. To derive such parameters we used thermal IR imaging cameras, acoustic recorders, and marine radar Furuno (XANK250), which was coupled with a XIR3000B digitizing card from Russell Technologies and open source radR processing software. The integration yielded a development of different computational techniques and methods, which we further developed and optimized as a combined surveillance system. To accomplish this task we implemented marine radar calibration, optimization of processing parameters, and fusion of the multi-sensor data in order to make inferences about the potential avian targets. The main goal of the data fusion from the multi-sensor environment was aimed at reduction of uncertainties while providing acceptable confidence levels with detailed information about the migration patterns. Another component comprised of an assessment of wind resources in a near lake environment and an investigation of the effectiveness of ice coating materials to mitigate adverse effects of ice formation on wind turbine structures. Firstly, a Zephir LiDAR system was acquired and installed at Woodlands School in Huron, Ohio, which is located near Lake Erie. Wind resource data were obtained at ten measurement heights, 200m, 150m, 100m, 80m, 60m, 40m, 38m, 30m, 20m, and 10m. The Woodlands School’s wind turbine anemometer also measured the wind speed at the hub height. These data were collected for approximately one year. The hub anemometer data correlated well with the LiDAR wind speed measurements at the same height. The data also showed that on several days different power levels were recorded by the turbine at the same wind speed as indicated by the hub anemometer. The corresponding LiDAR data showed that this difference can be attributed to variability in the wind over the turbine rotor swept area, which the hub anemometer could not detect. The observation suggests that single point hub wind velocity measurements are inadequate to accurately estimate the power generated by a turbine at all times since the hub wind speed is not a good indicator of the wind speed over the turbine rotor swept area when winds are changing rapidly. To assess the effectiveness of ice coatings to mitigate the impact of ice on turbine structures, a closed-loop icing research tunnel (IRT) was designed and constructed. By controlling the temperature, air speed, water content and liquid droplet size, the tunnel enabled consistent and repeatable ice accretion under a variety of conditions with temperatures between approximately 0°C and -20°C and wind speeds up to 40 miles per hour in the tunnel’s test section. The tunnel’s cooling unit maintained the tunnel temperature within ±0.2°C. The coatings evaluated in the study were Boyd Coatings Research Company’s CRC6040R3, MicroPhase Coatings Inc.’s PhaseBreak TP, ESL and Flex coatings. Similar overall performance was observed in all coatings tested in that water droplets form on the test articles beginning at the stagnation region and spreading in the downstream direction in time. When compari

Gorsevski, Peter; Afjeh, Abdollah; Jamali, Mohsin; Carroll, Michael

2014-04-09T23:59:59.000Z

444

Real time grid congestion management in presence of high penetration of wind energy  

E-Print Network [OSTI]

Real time grid congestion management in presence of high penetration of wind energy A. Vergnol1 , J », « Wind energy », « Variable speed drive » Abstract With the increased use of wind energy the power

Boyer, Edmond

445

Steady and Unsteady Wind Loading of Buildings and Structures [and Discussion  

Science Journals Connector (OSTI)

...terrain are briefly discussed. For design based on steady wind loadings the design wind speed is dependent on the acceptable degree of risk. Force and pressure coefficients may be influenced by Reynolds number, surface roughness, wind characteristics...

1971-01-01T23:59:59.000Z

446

Sensitivity analysis of offshore wind turbine tower caused by the external force  

Science Journals Connector (OSTI)

Generally, faster wind speeds are observed in coastal areas than ... inland areas. Therefore, for the development of offshore wind energy, more electricity is expected to be generated using wind turbines. This al...

Namhyeong Kim; Jung Woon Jin

2013-07-01T23:59:59.000Z

447

A hybrid measure-correlate-predict method for long-term wind condition assessment  

Science Journals Connector (OSTI)

Abstract This paper develops a hybrid measure-correlate-predict (MCP) strategy to assess long-term wind resource variations at a farm site. The hybrid MCP method uses recorded data from multiple reference stations to estimate long-term wind conditions at a target wind plant site with greater accuracy than is possible with data from a single reference station. The weight of each reference station in the hybrid strategy is determined by the (i) distance and (ii) elevation differences between the target farm site and each reference station. In this case, the wind data is divided into sectors according to the wind direction, and the MCP strategy is implemented for each wind direction sector separately. The applicability of the proposed hybrid strategy is investigated using five MCP methods: (i) the linear regression; (ii) the variance ratio; (iii) the Weibull scale; (iv) the artificial neural networks; and (v) the support vector regression. To implement the hybrid MCP methodology, we use hourly averaged wind data recorded at five stations in the state of Minnesota between 07-01-1996 and 06-30-2004. Three sets of performance metrics are used to evaluate the hybrid MCP method. The first set of metrics analyze the statistical performance, including the mean wind speed, wind speed variance, root mean square error, and mean absolute error. The second set of metrics evaluate the distribution of long-term wind speed; to this end, the Weibull distribution and the Multivariate and Multimodal Wind Distribution models are adopted. The third set of metrics analyze the energy production of a wind farm. The best hybrid MCP strategy from 256 different combinations of MCP algorithms and reference stations is investigated and selected. The results illustrate that the many-to-one correlation in such a hybrid approach can provide a more reliable prediction of long-term on-site wind variations than that provided by the one-to-one correlations. The accuracy of the hybrid MCP method is found to be highly sensitive to the combination of individual MCP algorithms and reference stations used. It is also observed that the best combination of MCP algorithms is influenced by the length of the concurrent short-term correlation period.

Jie Zhang; Souma Chowdhury; Achille Messac; Bri-Mathias Hodge

2014-01-01T23:59:59.000Z

448

Simulation and Optimization of Wind Farm Operations under Stochastic Conditions  

E-Print Network [OSTI]

generation model, wind speed model, and maintenance model. We provide practical insights gained by examining di erent maintenance strategies. To the best of our knowledge, our simulation model is the rst discrete-event simulation model for wind farm...

Byon, Eunshin

2011-08-08T23:59:59.000Z

449

A simulation-based planning system for wind turbine construction  

Science Journals Connector (OSTI)

Wind turbine construction is a challenging undertaking due to the need to lift heavy loads to high locations in conditions of high and variable wind speeds. These conditions create great risks to contractors during the turbine assembly process. This ...

Dina Atef; Hesham Osman; Moheeb Ibrahim; Khaled Nassar

2010-12-01T23:59:59.000Z

450

Pitfalls of modeling wind power using Markov chains  

E-Print Network [OSTI]

An increased penetration of wind turbines have given rise to a need for wind speed/power models that generate realistic synthetic data. Such data, for example, might be used in simulations to size energy storage or spinning ...

Kirtley, James L., Jr.

451

Calculation Method of Losses and Efficiency of Wind Generators  

Science Journals Connector (OSTI)

In the methods presented in this chapter, wind speed is used as the input data, ... conditions of the WG system, for example, wind turbine output, generator output, output power to the power grid, and various los...

Junji Tamura

2012-01-01T23:59:59.000Z

452

Dynamic Simulation of DFIG Wind Turbines on FPGA Boards  

E-Print Network [OSTI]

Dynamic Simulation of DFIG Wind Turbines on FPGA Boards Hao Chen, Student Member, IEEE, Song Sun is a friction coefficient. The wind turbine model is based on the relation between the upstream wind speed V w + 1 where p is the air density; Rw is the wind turbine radius; cp (A, (3) is the performance

Zambreno, Joseph A.

453

Low frequency noise from MW wind turbines --mechanisms of generation  

E-Print Network [OSTI]

Low frequency noise from MW wind turbines -- mechanisms of generation and its modeling Helge MW wind turbines -- mechanisms of generation and its modeling Department: Department of Wind Energy 3.6MW turbine 12 3.2 Noise as function of wind speed 12 3.3 Noise as function of rotor

454

Ris National Laboratory Satellite SAR applied in offshore wind  

E-Print Network [OSTI]

Risø National Laboratory Satellite SAR applied in offshore wind ressource mapping: possibilities is to quantify the regional offshore wind climate for wind energy application based on satellite SAR ·Study of 85SAR(m/s) Hasager, Dellwik, Nielsen and Furevik, 2004, Validation of ERS-2 SAR offshore wind-speed maps

455

WIND ENERGY Wind Energ. (2014)  

E-Print Network [OSTI]

WIND ENERGY Wind Energ. (2014) Published online in Wiley Online Library (wileyonlinelibrary Correspondence M. Wächter, ForWind-Center for Wind Energy Research, Institute of Physics, Carl Von Ossietzky on the operation of wind energy converters (WECs) imposing different risks especially in terms of highly dynamic

Peinke, Joachim

456

Wind Resource Map: Mexico | Open Energy Information  

Open Energy Info (EERE)

Wind Resource Map: Mexico Wind Resource Map: Mexico Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Wind Resource Map: Mexico Focus Area: Renewable Energy Topics: Potentials & Scenarios Website: www.altestore.com/howto/Reference-Materials/Wind-Resource-Map-Mexico/a Equivalent URI: cleanenergysolutions.org/content/wind-resource-map-mexico,http://clean Language: English Policies: Deployment Programs DeploymentPrograms: Technical Assistance This is on-shore wind resource map for rural power applications in Mexico. The map can be used to aid in appropriate siting of wind power installations. Please note that the wind speed classes are taken at 30 m (100 feet [ft]), instead of the usual 10 m (33 ft). Each wind power class should span two power densities. For example, Wind Power Class = 3

457

wind energy  

National Nuclear Security Administration (NNSA)

5%2A en Pantex to Become Wind Energy Research Center http:nnsa.energy.govfieldofficesnponpopressreleasespantex-become-wind-energy-research-center

458

Plans for US wind tunnel set to take off  

Science Journals Connector (OSTI)

... world's largest and most sophisticated wind-tunnel complex, to be used by aircraft manufacturer Boeing to speed up the development of successors to the ... to speed up the development of successors to the Boeing 747 jumbo jet.

Colin Macilwain

1994-07-28T23:59:59.000Z

459

Offshore winds using remote sensing techniques  

Science Journals Connector (OSTI)

Ground-based remote sensing instruments can observe winds at different levels in the atmosphere where the wind characteristics change with height: the range of heights where modern turbine rotors are operating. A six-month wind assessment campaign has been made with a LiDAR (Light Detection And Ranging) and a SoDAR (Sound Detection and Ranging) on the transformer/platform of the world's largest offshore wind farm located at the West coast of Denmark to evaluate their ability to observe offshore winds. The high homogeneity and low turbulence levels registered allow the comparison of LiDAR and SoDAR with measurements from cups on masts surrounding the wind farm showing good agreement for both the mean wind speed and the longitudinal component of turbulence. An extension of mean wind speed profiles from cup measurements on masts with LiDAR observations results in a good match for the free sectors at different wind speeds. The log-linear profile is fitted to the extended profiles (averaged over all stabilities and roughness lengths) and the deviations are small. Extended profiles of turbulence intensity are also shown for different wind speeds up to 161 m. Friction velocities and roughness lengths calculated from the fitted log-linear profile are compared with the Charnock model which seems to overestimate the sea roughness for the free sectors.

Alfredo Peńa; Charlotte Bay Hasager; Sven-Erik Gryning; Michael Courtney; Ioannis Antoniou; Torben Mikkelsen; Paul Sřrensen

2007-01-01T23:59:59.000Z

460

Simulations of an offshore wind farm using large eddy simulation and a torque-controlled actuator disc model  

E-Print Network [OSTI]

We present here a computational fluid dynamics (CFD) simulation of Lillgrund offshore wind farm, which is located in the {\\O}resund Strait between Sweden and Denmark. The simulation combines a dynamic representation of wind turbines embedded within a Large-Eddy Simulation CFD solver, and uses hr-adaptive meshing to increase or decrease mesh resolution where required. This allows the resolution of both large scale flow structures around the wind farm, and local flow conditions at individual turbines; consequently, the response of each turbine to local conditions can be modelled, as well as the resulting evolution of the turbine wakes. This paper provides a detailed description of the turbine model which simulates interactions between the wind, turbine rotors, and turbine generators by calculating the forces on the rotor, the body forces on the air, and instantaneous power output. This model was used to investigate a selection of key wind speeds and directions, investigating cases where a row of turbines would ...

Creech, Angus; Maguire, A Eoghan

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Wind energy resource in Northern Mexico  

Science Journals Connector (OSTI)

Abstract Mexico has installed less wind power compared to the other North American countries. Renewable energy sources only account for 3% of the energy mix in Mexico. The U.S. states bordering Mexico, namely Texas, New Mexico, Arizona, and California, have good wind power resources. Among them, Texas has the highest installed wind power capacity of 10.34 GW. The wind resources in these bordering states indicate that the wind energy resource in Northern Mexico must be assessed; thus, the spatial and temporal information about the wind energy resource was studied. The daily pattern of the wind speed, one per state studied, was obtained. The wind speed was found to exhibit a pattern; it increases from 4 pm until 6 am the following day. The main conclusions are that the state of Tamaulipas has the highest Wind Power Density (WPD) of 1000 W/m2 during September and October, but the north of Nuevo Leon has, in a large part of its territory, an annual WPD greater than 103 W/m2; each state has 1700 useful hours of wind speed above 3 m/s. Northern Mexico has some zones with excellent wind speed as well; the states of Chihuahua, Coahuila, Nuevo Leon and Tamaulipas have a wind speed of over 4.51 m/s across nearly their entire territories. Because Mexico in recent years has been starting to exploit renewable energy sources, the government has mandated energy reform, which improves the conditions for investment in wind energy in Mexico.

Q. Hernández-Escobedo; R. Saldańa-Flores; E.R. Rodríguez-García; F. Manzano-Agugliaro

2014-01-01T23:59:59.000Z

462

Direct - drive permanent magnet synchronous generator design for hydrokinetic energy extraction .  

E-Print Network [OSTI]

??"Hydrokinetic turbines deliver lower shaft speeds when compared to both steam and wind turbines. Hence, a water wheel generator must operate at speeds as low… (more)

Kashyap, Amshumaan Raghunatha

2013-01-01T23:59:59.000Z

463

This document will help you understand the statistics commonly used to describe wind when it is studied  

E-Print Network [OSTI]

Resource Assessment Wind Data Permitting Case Studies 1. 2. 3. 4. 5. 6. 7. Wind Statistics 6 Inside this Edition: Wind Data Overview p. 1 Wind Statistics p. 1 Graphs p. 2 For more information p. 2 Wind speedsThis document will help you understand the statistics commonly used to describe wind when

Massachusetts at Amherst, University of

464

Wind Energy  

Broader source: Energy.gov (indexed) [DOE]

FUPWG Meeting FUPWG Meeting NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy operated by the Alliance for Sustainable Energy, LLC Robi Robichaud November 18, 2009 Topics Introduction Review of the Current Wind Market Drivers for Wind Development Siting g Issues Wind Resource Assessment Wind Characteristics Wind Power Potential Basic Wind Turbine Theory Basic Wind Turbine Theory Types of Wind Turbines Facts About Wind Siting Facts About Wind Siting Wind Performance 1. United States: MW 1 9 8 2 1 9 8 3 1 9 8 4 1 9 8 5 1 9 8 6 1 9 8 7 1 9 8 8 1 9 8 9 1 9 9 0 1 9 9 1 1 9 9 2 1 9 9 3 1 9 9 4 1 9 9 5 1 9 9 6 1 9 9 7 1 9 9 8 1 9 9 9 2 0 0 0 2 0 0 1 2 0 0 2 2 0 0 3 2 0 0 4 2 0 0 5 2 0 0 6 2 0 0 7 2 0 0 8 Current Status of the Wind Industry Total Global Installed Wind Capacity Total Global Installed Wind Capacity Total Global Installed Wind Capacity

465

Data Collection for the Bonneville Power Administration Project on Wind Loading of Transmission Conductors  

Science Journals Connector (OSTI)

ABSTRACT The Bonneville Power Administration (BPA) project, “Wind Effects on Conductors for Span Factors” was established to determine the relationship between actual and theoretical wind loads on overhead transmission conductors. This study aims to improve BPA transmission line design methods and criteria as they relate to wind conditions in the Pacific Northwest. For the past seven years, BPA has collected data from seven sites in the Pacific Northwest. Measurements of wind speeds and directions, ambient temperatures and barometric pressures, and conductor swing angles enable engineers to compare measured wind loads on conductors to theoretical values. Impact of such variables as height of conductor, span lengths and conductor diameter are also investigated. Three sites were instrumented with vertically arranged anemometers to measure wind speed as a function of height above ground. This paper covers site determination, instrumentation, data collection, and some site maintenance and operation challenges. The maintenance and manipulation of the very large data base that has been collected is discussed. As data analysis is not yet finished, final results are not included.

H.W. VOLPE

1987-01-01T23:59:59.000Z

466

INTEGRATION OF RENEWABLE ENERGY SYSTEMS TO ISOLATED DESERT SITE IN EGYPT. Part I: Wind System Optimisation  

Science Journals Connector (OSTI)

ABSTRACT This paper discusses the technical and economical studies and the conceptual system designs for using renewable energy sources such as photovoltaic (PV), wind and biogas supplemented by conventional energy sources as an integerated system to isolated desert site south west of Egypt. (East Oweinat). The first part deals with the wind system optimisation . An attempt has been done, to find an analytical expression and graphical presentation for the proper tower height of a given Wind Energy Conversion System (WECS). This height is expressed as a function of both WECS characteristic speeds (Vci & Vr), and parameters of the site wind speed frequency distribution(WSFD). Application of the derived formula at different sites, and upon various WECS's shows that installing the WECS at that height ensures a high capacity factor of not less than 0.4 for the WECS. The paper also presents the possibility of determining that height directly from the given nomogram. KEY WORDS Wind system optimisation; integrated renewable energy system; wind energy conversion system; desert development; optimum height.

M. Galal Osman; M. Galal Osman; Fathy M.H. Youssef; Sobhy M. Abdelkader; Fathy M.H. Youssef; Sobhy M. Abdelkader

1988-01-01T23:59:59.000Z

467

New England Wind Forum: Wind Power Policy in New England  

Wind Powering America (EERE)

Projects in New England Building Wind Energy in New England Wind Resource Wind Power Technology Economics Markets Siting Policy Renewable Energy Portfolio Standards State Renewable Energy Funds Federal Tax Incentives and Grants Net Metering and Interconnection Standards Pollutant Emission Reduction Policies Awareness Technical Challenges Issues Small Wind Large Wind Newsletter Perspectives Events Quick Links to States CT MA ME NH RI VT Bookmark and Share Wind Power Policy in New England Why Incentives and Policy? Federal and state policies play an important role in encouraging wind energy development by leveling the playing field compared to other energy sources. Many of the substantial benefits of wind power as a domestic, zero-emission part of the energy portfolio - sustainability, displacement of pollutant emissions from other power sources, fuel diversity, price stabilization, keeping a substantial portion of energy expenditures in the local economy - are shared by society as a whole and cannot be readily captured by wind generators directly in the price they charge for their output. In addition, while wind power receives some policy support, the level of federal incentives for wind represents less than 1% of the subsidies and tax breaks given to the fossil fuels and nuclear industries (source: "Wind Power An Increasingly Competitive Source of New Generation." Wind Energy Weekly #1130.).

468

Offshore Wind Potential Tables  

Wind Powering America (EERE)

Offshore wind resource by state and wind speed interval within 50 nm of shore. Offshore wind resource by state and wind speed interval within 50 nm of shore. Wind Speed at 90 m (m/s) 7.0 - 7.5 7.5 - 8.0 8.0 - 8.5 8.5 - 9.0 9.0 - 9.5 9.5 - 10.0 >10.0 Total >7.0 State Area km 2 (MW) Area km 2 (MW) Area km 2 (MW) Area km 2 (MW) Area km 2 (MW) Area km 2 (MW) Area km 2 (MW) Area km 2 (MW) California 11,439 (57,195) 24,864 (124,318) 23,059 (115,296) 22,852 (114,258) 13,185 (65,924) 15,231 (76,153) 6,926 (34,629) 117,555 (587,773) Connecticut 530 (2,652) 702 (3,508) 40 (201) 0 (0) 0 (0) 0 (0) 0 (0) 1,272 (6,360) Delaware 223 (1,116) 724 (3,618) 1,062 (5,310) 931 (4,657) 0 (0) 0 (0) 0 (0) 2,940 (14,701) Georgia 3,820 (19,102) 7,741 (38,706) 523 (2,617) 0 (0) 0 (0) 0 (0) 0 (0) 12,085 (60,425) Hawaii 18,873 (94,363) 42,298 (211,492)

469

Systems Performance Analyses of Alaska Wind-Diesel Projects; Kotzebue, Alaska (Fact Sheet)  

SciTech Connect (OSTI)

This fact sheet summarizes a systems performance analysis of the wind-diesel project in Kotzebue, Alaska. Data provided for this project include wind turbine output, average wind speed, average net capacity factor, and optimal net capacity factor based on Alaska Energy Authority wind data, estimated fuel savings, and wind system availability.

Baring-Gould, I.

2009-04-01T23:59:59.000Z

470

Impact of DFIG wind turbines on transient stability of power systems a review  

E-Print Network [OSTI]

Impact of DFIG wind turbines on transient stability of power systems ­ a review Authors Na Abstract of wind farms are using variable speed wind turbines equipped with doubly-fed induction generators (DFIG) due to their advantages over other wind turbine generators. Therefore, the analysis of wind power

Pota, Himanshu Roy

471

Short-term Wind Power Forecasting Using Advanced Statistical T.S. Nielsen1  

E-Print Network [OSTI]

Short-term Wind Power Forecasting Using Advanced Statistical Methods T.S. Nielsen1 , H. Madsen1 , H considered in the ANEMOS project for short-term fore- casting of wind power. The total procedure typically in for prediction of wind power or wind speed, estimating the uncertainty of the wind power forecast, and finally

Paris-Sud XI, Université de

472

Abstract--This paper addresses the problem of controlling wind energy conversion systems (WECS) which involve  

E-Print Network [OSTI]

Abstract-- This paper addresses the problem of controlling wind energy conversion systems (WECS-inverter. The goal of control is to maximize wind energy extraction and this needs letting the wind turbine rotor wind energy extraction) only for one wind speed value depending on the considered value of turbine

Paris-Sud XI, Université de

473

Prediction, operations, and condition monitoring in wind energy Andrew Kusiak a,*, Zijun Zhang b  

E-Print Network [OSTI]

Review Prediction, operations, and condition monitoring in wind energy Andrew Kusiak a,*, Zijun 2013 Available online 23 August 2013 Keywords: Wind energy Wind speed prediction Wind turbine control Condition monitoring and fault detection a b s t r a c t Recent developments in wind energy research

Kusiak, Andrew

474

The Use of Tall Tower Field Data for Estimating Wind Turbine Power Performance , J. Chapman1  

E-Print Network [OSTI]

The Use of Tall Tower Field Data for Estimating Wind Turbine Power Performance A. Swift1 , J wind speed measurements on the TTU WISE 200m and 78m towers. A hypothetical wind turbine is shown. At potential wind turbine sites, it is uncommon to have wind measurements available at multiple heights. Then

Manuel, Lance

475

RAIN AND WIND ESTIMATION FROM SEAWINDS IN HURRICANES AT ULTRA HIGH RESOLUTION  

E-Print Network [OSTI]

function (GMF) which relates wind to backscatter (0 ) is not well understood for extremely high wind speedsRAIN AND WIND ESTIMATION FROM SEAWINDS IN HURRICANES AT ULTRA HIGH RESOLUTION Brent A. Williams method for estimating wind and rain in hurricanes from SeaWinds at ultra-high resolution is developed. We

Long, David G.

476

NREL: Wind Research - Research Staff Biographies  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

and Eduard Muljadi on a soon-to-be-published history of Variable-Speed Operation of Wind Turbines. Photo of Corrie Christol Corrie Christol Administrative Project Manager, National...

477

Energy Analysis of Convectively Induced Wind Perturbations  

Science Journals Connector (OSTI)

Budgets of divergent and rotational components of kinetic energy (KD and KR) are examined for four upper level wind speed maxima that develop during the fourth Atmospheric Variability Experiment (AVE IV) and the first AVE-Severe Environmental ...

Henry E. Fuelberg; Dennis E. Buechler

1989-04-01T23:59:59.000Z

478

Power Performance Measurements of the NREL CART-2 Wind Turbine Using a Nacelle-Based Lidar Scanner  

Science Journals Connector (OSTI)

Different certification procedures in wind energy, such as power performance testing or load estimation, require measurements of the wind speed, which is set in relation to the electrical power output or the turbine loading. The wind shear affects ...

Andreas Rettenmeier; David Schlipf; Ines Würth; Po Wen Cheng

2014-10-01T23:59:59.000Z

479

Study of Stability Analysis of a Grid-Connected Doubly Fed Induction Generator (DFIG)-based small Wind Farm.  

E-Print Network [OSTI]

??Wind is the most reliable, clean and fast-developing renewable energy source. The DFIG-based variable speed wind turbine system is now the most popular in wind… (more)

Dhar, Baishakhi

2013-01-01T23:59:59.000Z

480

Assessing the Impacts of Reduced Noise Operations of Wind Turbines on Neighbor Annoyance: A Preliminary Analysis in Vinalhaven, Maine  

E-Print Network [OSTI]

of Reduced Noise Operations of Wind Turbines on Neighborof Reduced Noise Operations of Wind Turbines on NeighborWind Speed (m/s) 3 Turbines (in operation at the time) Noise

Hoen, Ben

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "wind speed direction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

Q. J. R. Meteorol. Soc. (2004), 130, pp. 120 Using mesocale model winds for correcting wind-drift errors in radar  

E-Print Network [OSTI]

the vertical shear of the horizontal wind. We assume the shear and the fall speed in the layer are constant rain because of the low fall speed of around 1 m s-1. Sampling these wind-induced fall streak patterns vertical profile of reflectivity shear fall streak wind drift 1. Introduction Operational radars around

Reading, University of

482

Wind extremes in the North Sea Basin under climate change: An ensemble study of 12 CMIP5 GCMs  

E-Print Network [OSTI]

Wind extremes in the North Sea Basin under climate change: An ensemble study of 12 CMIP5 GCMs R. C levels and waves are generated by low atmospheric pressure and severe wind speeds during storm events. As a result of the geometry of the North Sea, not only the maximum wind speed is relevant, but also wind

Haak, Hein

483

Experimental investigation of the effect of combined hydrogen and diesel combustion on the particulate size distribution from a high speed direct injection diesel engine  

Science Journals Connector (OSTI)

The effects of hydrogen addition and exhaust gas recirculation (EGR) levels on the exhaust particulate matter size distribution in a diesel engine have been investigated. The experiments were performed on a 2.0 litre, 4-cylinder, direct injection engine equipped with a modern high-pressure common rail. A nano-Micro-Orifice Uniform Deposit Impactor (nano-MOUDI) was used in this work to study the particulate matter size distribution. All tests were conducted at the set operating point of 1,500 rpm. The experimental work showed that the particulate matter size distribution was not dramatically altered by the addition of EGR, but the main peak was shifted towards the nucleation mode with the addition of hydrogen. The addition of hydrogen increases the emissions of nitrogen oxides (NOx), but reduces the emissions of unburnt hydrocarbons (THC). Conversely, the addition of EGR reduces NOx, but can increase THC. Hydrogen addition increases the peak cylinder pressure and the maximum rate of pressure rise.

L. McWilliam; A. Megaritis

2009-01-01T23:59:59.000Z

484

Wind Mills  

Science Journals Connector (OSTI)

Over 5,000 years ago, the ancient Egyptians used wind to sail ships on the Nile River. While the proliferation of water mills was in full swing, windmills appeared to harness more inanimate energy by employing wind

J. S. Rao

2011-01-01T23:59:59.000Z

485

Wind Farm  

Office of Energy Efficiency and Renewable Energy (EERE)

The wind farm in Greensburg, Kansas, was completed in spring 2010, and consists of ten 1.25 megawatt (MW) wind turbines that supply enough electricity to power every house, business, and municipal...

486

Wind Power  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Wind Power As the accompanying map of New Mexico shows, the best wind power generation potential near WIPP is along the Delaware Mountain ridge line of the southern Guadalupe...

487