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Note: This page contains sample records for the topic "measure wind speed" 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

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

2

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

3

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

4

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

5

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

6

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

7

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

8

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

9

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

10

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

11

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

12

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

13

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

14

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

15

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

16

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

17

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

18

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

19

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

20

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

Note: This page contains sample records for the topic "measure wind speed" 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

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)

22

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

23

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

24

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

25

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

26

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

27

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

28

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

29

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

30

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

31

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

32

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

33

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

34

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

35

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

36

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

37

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

38

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

39

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

40

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

Note: This page contains sample records for the topic "measure wind speed" 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

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

42

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....

43

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....

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

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

46

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.

47

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

48

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

49

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

50

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

51

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

52

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...

53

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

54

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

55

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

56

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

57

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

58

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

59

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

60

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

Note: This page contains sample records for the topic "measure wind speed" 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

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

62

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

63

QUIKSCAT MEASUREMENTS AND ECMWF WIND FORECASTS  

E-Print Network [OSTI]

. (2004) this forecast error was encountered when assimilating satellite measurements of zonal wind speeds between satellite measurements and meteorological forecasts of near-surface ocean winds. This type of covariance enters in assimilation techniques such as Kalman filtering. In all, six residual fields

Malmberg, Anders

64

QUIKSCAT MEASUREMENTS AND ECMWF WIND FORECASTS  

E-Print Network [OSTI]

. (2004) this forecast error was encountered when assimilating satellite measurements of zonal wind speeds between satellite measurements and meteorological forecasts of near­surface ocean winds. This type of covariance enters in assimilation techniques such as Kalman filtering. In all, six residual fields

Malmberg, Anders

65

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

66

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.

67

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

68

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

69

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

70

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

71

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.

72

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

73

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

74

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

75

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

76

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

77

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

78

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

79

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

80

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

Note: This page contains sample records for the topic "measure wind speed" 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

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...

82

NACA0015 Measurements in LM Wind Tunnel and Turbulence  

E-Print Network [OSTI]

NACA0015 Measurements in LM Wind Tunnel and Turbulence Generated Noise Franck Bertagnolio Risø, Denmark November 2008 #12;Author: Franck Bertagnolio Title: NACA0015 Measurements in LM Wind Tunnel on its surface and measured in the wind tunnel at LM Glasfiber at various inflow speeds, angles of attack

83

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

84

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

85

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)

86

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...

87

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

88

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

89

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

90

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)

91

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

92

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

93

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.

94

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)

95

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

96

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

97

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

98

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

99

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.

100

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

Note: This page contains sample records for the topic "measure wind speed" 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

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

102

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

103

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

104

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

105

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.

106

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

107

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

108

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

109

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

110

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.

111

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

112

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

113

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

114

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

115

Dispersal of measured sound power levels for wind turbines  

Science Journals Connector (OSTI)

The standard IEC 61400?11 provides guidance in the measurement analysis and reporting of acoustic emissions(sound power levels) from wind turbine generator systems. The application of this standard aims to provide accurate results that can be replicated by others. We did several measurement operations according to this standard on various wind farms fitted with many turbine manufacturers on different ground types. Important differences have been noticed with equal working conditions between the most and the less noisy wind turbine on a single farm. We will present these results compared to the manufacturers' guaranteed values and initiate explanations (like the difficulties to link the wind speed at 10m above ground with the wind speed received at hub height; or the influence of wind incidence on blades).

René Gamba; Sébastien Garrigues

2008-01-01T23:59:59.000Z

116

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

117

Comparison of Wake Model Simulations with Offshore Wind Turbine Wake Profiles Measured by Sodar  

Science Journals Connector (OSTI)

This paper gives an evaluation of most of the commonly used models for predicting wind speed decrease (wake) downstream of a wind turbine. The evaluation is based on six experiments where free-stream and wake wind speed profiles were measured ...

R. J. Barthelmie; G. C. Larsen; S. T. Frandsen; L. Folkerts; K. Rados; S. C. Pryor; B. Lange; G. Schepers

2006-07-01T23:59:59.000Z

118

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

119

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

120

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

Note: This page contains sample records for the topic "measure wind speed" 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

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

122

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.

123

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

124

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

125

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

126

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

127

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

128

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

129

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

130

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

131

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

132

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

133

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

134

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

135

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

136

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

137

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

138

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

139

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

140

Position and attitude measurement of high-speed isolates for hypersonic facilities  

Science Journals Connector (OSTI)

Abstract The position and attitude measurement of high-speed isolates for hypersonic facilities plays an important role in structural design and aerodynamic analysis for the core facilities of aeronautics, astronautics, and navigation industries. One of the important high-speed isolates for hypersonic facilities is the high-speed and rolling target. In this paper, a rapid position and attitude measurement method based on binocular vision theory has been proposed for high-speed and rolling target in the dark wind tunnel environment. Firstly, by selecting and combining the proper light and markers, high-resolution images of the high-speed and rolling target are captured by two high-speed CCD cameras in the dark and complicated wind tunnel. Then, an acceleration–helix layout of markers is proposed to solve the markers hidden-phenomenon during the rolling procedure of for the elongated high-speed target in the larger space. Moreover, the high-accuracy recognition of the corresponding markers in the images is achieved on the basis of the markers layout. Then, position and attitude parameters of the high-speed and rolling target are calculated according to the recognized markers on the surface of the rolling target. Finally, simulative experiments on measuring the pose parameters of the rolling target in wind tunnel are conducted, and the experimental results indicate that the proposed measuring method is effective. Besides, an additional experiment in the laboratory verifies that the measurement accuracy can meet the measuring requirements in wind tunnel facilities.

Wei Liu; Xin Ma; Zhenyuan Jia; Yang Zhang; Zhiliang Shang; Xiao Li

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "measure wind speed" 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

MEASURING IMPACTS TO BIRDS CAUSED BY WIND TURBINES MEASURING IMPACTS TO BIRDS CAUSED BY WIND TURBINES  

E-Print Network [OSTI]

APPENDIX A MEASURING IMPACTS TO BIRDS CAUSED BY WIND TURBINES #12;A-1 APPENDIX A MEASURING IMPACTS TO BIRDS CAUSED BY WIND TURBINES 1.0 INTRODUCTION Differential composition of wind turbines at wind energy used is the number of fatalities per wind turbine per year (Anderson et al. 1999). This metric has

142

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.

143

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

144

Measuring the speed of cosmological gravitational waves  

E-Print Network [OSTI]

In general relativity gravitational waves propagate at the speed of light, however in alternative theories of gravity that might not be the case. We study the effects of a modified speed of gravity, $c_T^2$, on the B-modes of the Cosmic Microwave Background (CMB) anisotropy in polarisation. We find that a departure from the light speed value would leave a characteristic imprint on the BB spectrum part induced by tensors, manifesting as a shift in the angular scale of its peaks. We derive constraints by using the available {\\it Planck} and BICEP2 datasets showing how $c_T^2$ can be measured, albeit obtaining weak constraints due to the overall poor accuracy of the current BB power spectrum measurements. The present constraint corresponds to $c_T^2 = 1.30 \\pm 0.79$ and $c_T^2measurements, largely due to the absence of degeneracy with other cosmological parameters.

Marco Raveri; Carlo Baccigalupi; Alessandra Silvestri; Shuang-Yong Zhou

2014-05-30T23:59:59.000Z

145

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

146

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

147

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

148

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

149

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

150

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

151

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

152

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

153

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

154

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

155

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

156

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

157

Measuring the speed of cosmological gravitational waves  

E-Print Network [OSTI]

We study the effects of a modified speed of gravitational waves (tensor modes), $c_T^2$ on the B-modes of the Cosmic Microwave Background (CMB) anisotropy in polarisation. We find that a departure from the light speed value would leave a characteristic imprint on the BB spectrum part induced by tensors, manifesting as a shift in the angular scale of its peaks. We derive constraints by using the available Planck and BICEP2 datasets showing how $c_T^2$ can be measured, albeit obtaining weak constraints due to the overall poor accuracy of the current BB power spectrum measurements. The present constraint corresponds to $c_T^2 = 1.30 \\pm 0.79$ and $c_T^2measurements, largely due...

Raveri, Marco; Zhou, Shuang-Yong

2014-01-01T23:59:59.000Z

158

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

159

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

160

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

Note: This page contains sample records for the topic "measure wind speed" 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

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

162

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

163

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

164

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

165

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

166

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

167

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

168

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

169

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

170

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

171

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

172

Solar wind electron temperature and density measurements on the Solar Orbiter with thermal noise spectroscopy  

E-Print Network [OSTI]

Solar wind electron temperature and density measurements on the Solar Orbiter with thermal noise of the plasma thermal noise analysis for the Solar Orbiter, in order to get accurate measurements of the total of their small mass and therefore large thermal speed, the solar wind electrons are expected to play a major role

California at Berkeley, University of

173

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

174

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

175

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...

176

Measuring the Speed of Light Lab Manual by  

E-Print Network [OSTI]

Measuring the Speed of Light Lab Manual by: Eric Mueller Dan Passmore #12;Introduction When you to measure the speed of light. Nearly by definition, there is nothing fast enough to trip a clock on light want to measure the speed of something, how do you do it? Generally, you measure off a specific

Dai, Pengcheng

177

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

178

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

179

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

180

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

Note: This page contains sample records for the topic "measure wind speed" 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

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

182

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

183

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

184

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

185

ccsd00000548 COMMENTS ON "MEASURING THE GRAVITY SPEED BY VLBI"  

E-Print Network [OSTI]

ccsd­00000548 (version 1) : 18 Aug 2003 COMMENTS ON "MEASURING THE GRAVITY SPEED BY VLBI" H. ASADA the light speed. Such a di#11;erence may play a vital role in the primordial universe. In recent, Kopeikin and Fomalont claimed the #12;rst measurement of the gravity speed by VLBI. However, the measurement has

186

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

187

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

188

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

189

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

190

Acoustic wind and wind?shear measuring system  

Science Journals Connector (OSTI)

An acoustic wind?profiling system designed to detect hazardous wind?shear conditions in the airport environment has been developed during the past four years. The system installed at Dulles International Airport consists of a vertically pointed transmitter surrounded by three receivers 290?m distant and separated by 120° in azimuth. Electronically steered receiver beams track the upward propagating transmitted tone burst and collect the scatteredacoustic signals. The Doppler frequency shift of the returns is analyzed digitally to determine the horizontal wind at 20 height levels in 30?m increments. Unique design features of the system such as the steered receiver antenna are described. A one?leg prototype of the Dulles system was installed and tested at Table Mountain near Boulder CO. Winds measured by the prototype acoustic system compared well with those determined by an FM?CW radar and a balloon?borne anemometer. Noisegenerated by rain and surface winds exceeding 16 m sec?1 proved to be the major limitations for the acoustic system. Preliminary results from the Dulles system are also presented.

P. A. Mandics; D. W. Beran

1976-01-01T23:59:59.000Z

191

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

192

Measurements of the source level of ambient noise due to wind  

Science Journals Connector (OSTI)

Measurements of the source level of wind?generated ambient noise in the deep ocean are presented for the frequency band 10–350 Hz. The data were obtained using a vertical line array deployed in the deep sound channel at various sites in the Northeast Pacific. The array response was steered vertically upward to measure the local sea surface noise and eliminate distant shipping noise. The beamforming was carried out in the frequency domain using a Kaiser?Bessel window to reduce sidelobe levels. The beam power levels obtained were referenced to a source level at the sea surface using a simple propagation model. The estimated wind noise levels N were fitted to the wind speed v at a specific frequency using a model of the form N = A + 20 n log v. The data indicate two we!l?defined regions with a weak wind?speed dependence at low wind speeds before wave breaking occurs and a stronger dependence at higher wind speeds. The values of n for wind speeds > 10 kn were in the range from 1.1–1.8. The source levels are compared with other measurements reported in the literature.

N. Ross Chapman; James W. Cornish

1990-01-01T23:59:59.000Z

193

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

194

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

195

High-Pressure Flame Speed Measurements  

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

addition on flame speeds of hydrocarbon fuels 3. Soot formation and explosive gasification in burning droplets of dieselbiodieselethanol blends C. K. Law Princeton...

196

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

197

Measuring the Impacts of Speed Reduction Technologies  

E-Print Network [OSTI]

-Seoud, Edward Anderson #12;Background Identified as a problem area Sharp curve & excessive speed High crash;Comparison of Mean Zones - Southbound, Commercial Vehicles 45 46 47 48 49 50 51 52 53 54 55 -1300 -1100 -900-70 Speed Category Before After #12;At nearest rest area

Bertini, Robert L.

198

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

199

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

200

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

Note: This page contains sample records for the topic "measure wind speed" 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.


201

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

202

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

203

Measured and predicted rotor performance for the SERI advanced wind turbine blades  

SciTech Connect (OSTI)

Measured and predicted rotor performance for the SERI advanced wind turbine blades were compared to assess the accuracy of predictions and to identify the sources of error affecting both predictions and measurements. An awareness of these sources of error contributes to improved prediction and measurement methods that will ultimately benefit future rotor design efforts. Propeller/vane anemometers were found to underestimate the wind speed in turbulent environments such as the San Gorgonio Pass wind farm area. Using sonic or cup anemometers, good agreement was achieved between predicted and measured power output for wind speeds up to 8 m/sec. At higher wind speeds an optimistic predicted power output and the occurrence of peak power at wind speeds lower than measurements resulted from the omission of turbulence and yaw error. In addition, accurate two-dimensional (2-D) airfoil data prior to stall and a post stall airfoil data synthesization method that reflects three-dimensional (3-D) effects were found to be essential for accurate performance prediction. 11 refs.

Tangler, J.; Smith, B.; Kelley, N.; Jager, D.

1992-02-01T23:59:59.000Z

204

Wind Scanner: A full-scale Laser Facility for Wind and Turbulence Measurements around large Wind Turbines  

E-Print Network [OSTI]

measurements of the wind fields engulfing today's huge wind turbines. Our aim is to measure in real- time 3D velocity field, ,within the volumes that fully surround the huge wind turbines of today and tomorrow atmospheric flow that surrounds the giant wind turbines. This new knowledge we envision will accelerate

205

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

206

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

207

A New Method of Measuring Sperm Speeds  

Science Journals Connector (OSTI)

... the following footnote occurs on p. 89: "Fiirthmade systematic counts of the number of pedestrians in a [street] block every five seconds.... It is amusing that by ... kind made by Furth it is possible actually to determine the average speed of a pedestrian !" The principle involved in such determinations is known as probability-after-effect, and ...

LORD ROTHSCHILD

1953-03-21T23:59:59.000Z

208

Airborne Doppler Lidar Wind Field Measurements  

Science Journals Connector (OSTI)

A coherent Doppler lidar has been used in an aircraft to measure the 2-dimensional wind field in a number of different atmospheric situations. The lidar, a pulsed CO2 system, was installed in the NASA Convair 990. Galileo II, and flown in a ...

J. Bilbro; G. Fichtl; D. Fitzjarrald; M. Krause; R. Lee

1984-04-01T23:59:59.000Z

209

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

210

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

211

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

212

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

213

Concept of spinsonde for multi-cycle measurement of vertical wind profile of tropical cyclones  

E-Print Network [OSTI]

Tropical cyclones and cyclogenesis are active areas of research. Chute-operated dropsondes jointly developed by NASA and NCAR are capable of acquiring high resolution vertical wind profile of tropical cyclones. This paper proposes a chute-free vertical retardation technique (termed as spinsonde) that can accurately measure vertical wind profile. Unlike the expendable dropsondes, the spinsonde allows multi-cycle measurement to be performed within a single flight. Proof of principle is demonstrated using a simulation software and results indicate that the GPS ground speed correlates with the wind speeds to within +/-5 km/h. This technique reduces flying weight and increases payload capacity by eliminating bulky chutes. Maximum cruising speed (Vh) achieved by the spinsonde UAV is 372 km/h.

Poh, Chung-How

2014-01-01T23:59:59.000Z

214

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

215

An evaluation of inductance loop detectors for speed measurement accuracy  

E-Print Network [OSTI]

. The lag time from the presence of a vehicle at an inductance loop to the actual detection of a vehicle varies. As the lag time varies so does the accuracy of speed measurement. Vehicle size, vehicle speed, detector type, detector sensitivity...

Cronin, Brian Patrick

2012-06-07T23:59:59.000Z

216

Solar wind electron density and temperature over solar cycle 23: Thermal noise measurements on Wind  

E-Print Network [OSTI]

Solar wind electron density and temperature over solar cycle 23: Thermal noise measurements on Wind; received in revised form 6 April 2005; accepted 25 April 2005 Abstract We present the solar wind plasma parameters obtained from the Wind spacecraft during more than nine years, encompassing almost the whole solar

California at Berkeley, University of

217

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

218

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

219

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

220

Wind Measurement Equipment: Registration (Nebraska) | Department of Energy  

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

Wind Measurement Equipment: Registration (Nebraska) Wind Measurement Equipment: Registration (Nebraska) Wind Measurement Equipment: Registration (Nebraska) < Back Eligibility Agricultural Commercial Construction Fed. Government Fuel Distributor General Public/Consumer Industrial Installer/Contractor Institutional Investor-Owned Utility Local Government Low-Income Residential Multi-Family Residential Municipal/Public Utility Nonprofit Residential Retail Supplier Rural Electric Cooperative Schools State/Provincial Govt Systems Integrator Transportation Tribal Government Utility Savings Category Wind Buying & Making Electricity Program Info State Nebraska Program Type Siting and Permitting Provider Department of Aeronautics All wind measurement equipment associated with the development or study of wind-powered electric generation, whether owned or leased, shall be

Note: This page contains sample records for the topic "measure wind speed" 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

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

222

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

223

Vermont Wind Measurement Company Still Strong | Department of Energy  

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

Vermont Wind Measurement Company Still Strong Vermont Wind Measurement Company Still Strong Vermont Wind Measurement Company Still Strong April 9, 2010 - 3:16pm Addthis NRG's new building utilizes solar power, but their products measure wind potential. | Photo courtesy NRG Systems NRG's new building utilizes solar power, but their products measure wind potential. | Photo courtesy NRG Systems Joshua DeLung NRG Systems, of Hinesburg, Vt., has made products to help its customers measure and understand the potential of wind energy since 1982. Now, because of additional opportunities the Recovery Act has created for renewable energy companies, small businesses such as NRG Systems are poised to grow with the increased demand for proven wind measurement and turbine control equipment. NRG Systems' customers are primarily developers, utilities and research

224

Vermont Wind Measurement Company Still Strong | Department of Energy  

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

Vermont Wind Measurement Company Still Strong Vermont Wind Measurement Company Still Strong Vermont Wind Measurement Company Still Strong April 9, 2010 - 3:16pm Addthis NRG's new building utilizes solar power, but their products measure wind potential. | Photo courtesy NRG Systems NRG's new building utilizes solar power, but their products measure wind potential. | Photo courtesy NRG Systems Joshua DeLung NRG Systems, of Hinesburg, Vt., has made products to help its customers measure and understand the potential of wind energy since 1982. Now, because of additional opportunities the Recovery Act has created for renewable energy companies, small businesses such as NRG Systems are poised to grow with the increased demand for proven wind measurement and turbine control equipment. NRG Systems' customers are primarily developers, utilities and research

225

Measuring the Isotopic Composition of Solar Wind Noble Gases  

E-Print Network [OSTI]

noble gases. #12;Exploring the Solar Wind94 Light solar wind noble gases were directly measured by mass of the light gases are known to vary with energy, so none of these provided solar isotopic and elemental5 Measuring the Isotopic Composition of Solar Wind Noble Gases Alex Meshik, Charles Hohenberg, Olga

226

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

227

Measurement of CNGS muon neutrino speed with Borexino  

E-Print Network [OSTI]

We have measured the speed of muon neutrinos with the Borexino detector using short-bunch CNGS beams. The final result for the difference in time-of-flight between a =17 GeV muon neutrino and a particle moving at the speed of light in vacuum is {\\delta}t = 0.8 \\pm 0.7stat \\pm 2.9sys ns, well consistent with zero.

Borexino Collaboration

2012-07-30T23:59:59.000Z

228

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

229

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

230

Measured effect of wind generation on the fuel consumption of an isolated diesel power system  

SciTech Connect (OSTI)

The Block Island Power Company (BIPCO), on Block Island, Rhode Island, operates an isolated electric power system consisting of diesel generation and an experimental wind turbine. The 150-kW wind turbine, designated MOD-OA by the U.S. Department of Energy is typically operated in parallel with two diesel generators to serve an average winter load of 350 kW. Wind generation serves up to 60% of the system demand depending on wind speed and total system load. Results of diesel fuel consumption measurements are given for the diesel units operated in parallel with the wind turbine and again without the wind turbine. The fuel consumption data are used to calculate the amount of fuel displaced by wind energy. Results indicate that the wind turbine displaced 25,700 lbs. of the diesel fuel during the test period, representing a calculated reduction in fuel consumption of 6.7% while generating 11% of the total electrical energy. The amount of displaced fuel depends on operating conditions and system load. It is also shown that diesel engine throttle activity resulting from wind gusts which rapidly change the wind turbine output do not significantly influence fuel consumption.

Stiller, P.; Scott, G.; Shaltens, R.

1983-06-01T23:59:59.000Z

231

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

232

Measuring the speed of dark: Detecting dark energy perturbations  

SciTech Connect (OSTI)

The nature of dark energy can be probed not only through its equation of state but also through its microphysics, characterized by the sound speed of perturbations to the dark energy density and pressure. As the sound speed drops below the speed of light, dark energy inhomogeneities increase, affecting both cosmic microwave background and matter power spectra. We show that current data can put no significant constraints on the value of the sound speed when dark energy is purely a recent phenomenon, but can begin to show more interesting results for early dark energy models. For example, the best fit model for current data has a slight preference for dynamics [w(a){ne}-1], degrees of freedom distinct from quintessence (c{sub s{ne}}1), and early presence of dark energy [{Omega}{sub de}(a<<1){ne}0]. Future data may open a new window on dark energy by measuring its spatial as well as time variation.

Putter, Roland de [Berkeley Lab and University of California, Berkeley, California 94720 (United States); Huterer, Dragan [Department of Physics, University of Michigan, 450 Church Street, Ann Arbor, Michigan, 48109 (United States); Linder, Eric V. [Berkeley Lab and University of California, Berkeley, California 94720 (United States); Institute for the Early Universe, Ewha Womans University, Seoul (Korea, Republic of)

2010-05-15T23:59:59.000Z

233

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

234

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

235

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

236

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

237

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

238

Measurement of the Speed of Light. II. Wavelength Measurements and Conclusion  

Science Journals Connector (OSTI)

30 June 1977 research-article Measurement of the Speed of Light. II. Wavelength Measurements and Conclusion T. G...this wavelength measurement leads to a value for the speed of light in vacuum of 299 792 459.0 0.6 m/s (Blaney et...

1977-01-01T23:59:59.000Z

239

Measurement of the Speed of Light. I. Introduction and Frequency Measurement of a Carbon Dioxide Laser  

Science Journals Connector (OSTI)

30 June 1977 research-article Measurement of the Speed of Light. I. Introduction and Frequency Measurement of a Carbon...part II following, describe a determination of the speed of light made by measuring the frequency and wavelength of radiation...

1977-01-01T23:59:59.000Z

240

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

Note: This page contains sample records for the topic "measure wind speed" 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.
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to obtain the most current and comprehensive results.


241

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

242

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

243

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

244

One-Way Speed of Light Measurements Without Clock Synchronisation  

E-Print Network [OSTI]

The 1991 DeWitte double one-way 1st order in v/c experiment successfully measured the anisotropy of the speed of light using clocks at each end of the RF coaxial cables. However Spavieri et al., Physics Letters A (2012), doi: 10.1016/j.physleta_2012.0010, have reported that (i) clock effects caused by clock transport should be included, and (ii) that this additional effect cancels the one-way light speed timing effect, implying that one-way light speed experiments "do not actually lead to the measurement of the one-way speed of light or determination of the absolute velocity of the preferred frame". Here we explain that the Spavieri et al. derivation makes an assumption that is not always valid: that the propagation is subject to the usual Fresnel drag effect, which is not the case for RF coaxial cables. As well DeWitte did take account of the clock transport effect. The Spavieri et al. paper has prompted this clarification of these issues.

Reginald T. Cahill

2012-06-04T23:59:59.000Z

245

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

246

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

247

FEASIBILITY ASSESSMENT OF SIMULTANEOUS OCEAN WIND AND CURRENT MEASUREMENTS  

E-Print Network [OSTI]

FEASIBILITY ASSESSMENT OF SIMULTANEOUS OCEAN WIND AND CURRENT MEASUREMENTS Ad Stoffelen, Jos de capability with sufficient accuracy for surface current estimation. Scatterometer Ocean Vector Wind (OVW-nadir measurement configuration. Sea surface current signature is one component of ocean surface motion. Several

Stoffelen, Ad

248

The Influence of Sampling and Filtering on Measured Wind Gusts  

Science Journals Connector (OSTI)

The theory by Rice for extreme value statistics is used to study the influence of filters in a wind measuring system on the measured gusts. An extension is made to discretely sampled data. Model results are compared with strong wind data from the ...

A. C. M. Beljaars

1987-12-01T23:59:59.000Z

249

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

250

Low-Cost Wind Speed Measurements Using Naphthalene Evaporation  

Science Journals Connector (OSTI)

Six 125-cm3 metal mesh cages, filled with 99% pure naphthalene mothballs, were suspended near anemometers during 8 winter weeks. Each week the cages were weighed to determine how much evaporation had occurred. A least-squares linear regression of ...

Pierre Y. Bernier

1988-10-01T23:59:59.000Z

251

field measurement of the speed of propagation of wind waves  

Science Journals Connector (OSTI)

of an AC bridge. The output of the bridge was rectified and recorded on a Minne- .... where 11 is the wave height, and thus H/X is the wave steepness. Using the ...

252

Application of measured loads to wind turbine fatigue and reliability analysis  

SciTech Connect (OSTI)

Cyclic loadings produce progressive damage that can ultimately result in wind turbine structural failure. There are many issues that must be dealt with in turning load measurements into estimates of component fatigue life. This paper deals with how the measured loads can be analyzed and processed to meet the needs of both fatigue life calculations and reliability estimates. It is recommended that moments of the distribution of rainflow-range load amplitudes be calculated and used to characterize the fatigue loading. These moments reflect successively more detailed physical characteristics of the loading (mean, spread, tail behavior). Moments can be calculated from data samples and functional forms can be fitted to wind conditions, such as wind speed and turbulence intensity, with standard recession techniques. Distributions of load amplitudes that accurately reflect the damaging potential of the loadings can be estimated from the moments at any, wind condition of interest. Fatigue life can then be calculated from the estimated load distributions, and the overall, long-term, or design spectrum can be generated for any particular wind-speed distribution. Characterizing the uncertainty in the distribution of cyclic loads is facilitated by using a small set of descriptive statistics for which uncertainties can be estimated. The effects of loading parameter uncertainty can then be transferred to the fatigue life estimate and compared with other uncertainties, such as material durability.

Veers, P.S. [Sandia National Labs., Albuquerque, NM (United States); Winterstein, S.R. [Stanford Univ., CA (United States)

1997-01-01T23:59:59.000Z

253

Stall inception measurements in a high-speed multistage compressor  

SciTech Connect (OSTI)

This paper presents unsteady measurements taken in a high-speed four-stage aeroengine compressor prior to the onset of aerodynamic flow instabilities. In this experiment, 40 fast-response pressure transducers have been located at various axial and circumferential positions throughout the machine in order to give a very detailed picture of stall inception. At all the compressor speeds investigated, the stall pattern observed is initiated by a very short length-scale finite-amplitude disturbance, which propagates at a fast rate around the annulus. This initial stall cell leads to a large-amplitude system instability in less than five rotor revolutions. Varying the IGV setting angle is found to have a strong influence on the axial location of the first disturbance detected. In particular, transferring the aerodynamic loading from front to down-stream stages moves the first disturbance detected from the first to the last stage of the compressor. Other repeatable features of the stall inception pattern in this compressor have been identified using a simple analysis technique particularly appropriate to the study of short length-scale disturbances. It is found that the origins of instabilities are tied to particular tangential positions in both the stationary and rotating frames of reference. These measurements lead to the conclusion that the stall inception process in high-speed multistage compressors can be characterized by some very local and organized flow phenomena. Moreover, there is no evidence of prestall waves in this compressor.

Escuret, J.F.; Garnier, V. [SNECMA, Moissy-Cramayel (France). Compressor Aerodynamics Dept.

1996-10-01T23:59:59.000Z

254

High-speed digital holographic interferometry for vibration measurement  

SciTech Connect (OSTI)

A system based on digital holographic interferometry for the measurement of vibrations is presented. A high-power continuous laser(10 W) and a high-speed CCD camera are used. Hundreds of holograms of an object that has been subjected to dynamic deformation are recorded. The acquisition speed and the time of exposure of the detector are determined by the vibration frequency. Two methods are presented for triggering the camera in order to acquire at a given phase of the vibration. The phase of the wavefront is calculated from the recorded holograms by use of a two-dimensional digital Fourier-transform method. The deformation of the object is obtained from the phase. By combination of the deformations recorded at different times it is possible to reconstruct the vibration of the object.

Pedrini, Giancarlo; Osten, Wolfgang; Gusev, Mikhail E

2006-05-20T23:59:59.000Z

255

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

256

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

257

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

258

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

259

WIND ATLAS FOR EGYPT: MEASUREMENTS, MICRO-AND MESOSCALE MODELLING  

E-Print Network [OSTI]

WIND ATLAS FOR EGYPT: MEASUREMENTS, MICRO- AND MESOSCALE MODELLING Niels G. Mortensen1 , Jens Energy Authority, Cairo, Egypt Ahmed El Sayed Yousef, Adel Mahmoud Awad, Mahmoud Abd-El Raheem Ahmed Meteorological Authority, Cairo, Egypt ABSTRACT The results of a comprehensive, 8-year wind resource assessment

260

The spatial response function of SeaWinds backscatter measurements  

E-Print Network [OSTI]

regions are used to produce images of the Earth's land and ice surfaces to support climate studies in a wide variety of studies, including ocean wind retrieval, sea-ice mapping and classification, iceberg are also collected over the land and ice areas of the Earth. SeaWinds measurements over these land and ice

Long, David G.

Note: This page contains sample records for the topic "measure wind speed" 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

Wind farm—Long term noise and vibration measurements  

Science Journals Connector (OSTI)

Most of the energy produced in Quebec comes from renewable sources. The concept of wind energy emerged in the late 1990’s and has since become a complementary source of energy alongside hydroelectricity. Wind farms are generally seen as a good sustainable way to produce energy. However they are not implemented without some impact on the environment. SNC-Lavalin Environment has performed many surveys in recent years for wind farm projects including noise measurements both before and after their commissioning. This presentation will give an overview of one such project where long term noise and vibration measurements where conducted. Vibration measurements as well as outdoor indoor and low frequencies noise measurements were completed both with and without the wind turbines in operation. Data will be presented showing different problems encountered in the analysis phase. For example multiple intermittent and non-steady noise sources were present during measurement (wind turbines car pass-bys wind in the trees human activities). Methods used to overcome these obstacles will be discussed (use of statistical parameters linear regression) and the effect of the wind turbine operation on the noise level (including low frequencies) and vibration level will be presented.

2013-01-01T23:59:59.000Z

262

Wind Farm - Long term noise and vibration measurements  

Science Journals Connector (OSTI)

Most of the energy produced in Quebec comes from renewable sources. The concept of wind energy emerged in the late 1990's and has since become a complementary source of energy alongside hydroelectricity. Wind farms are generally seen as a good sustainable way to produce energy. However they are not implemented without some impact on the environment. SNC-Lavalin Environment has performed many surveys in recent years for wind farm projects including noise measurements both before and after their commissioning. This presentation will give an overview of one such project where long term noise and vibration measurements where conducted. Vibration measurements as well as outdoor indoor and low frequencies noise measurements were completed both with and without the wind turbines in operation. Data will be presented showing different problems encountered in the analysis phase. For example multiple intermittent and non-steady noise sources were present during measurement (wind turbines car pass-bys wind in the trees human activities). Methods used to overcome these obstacles will be discussed (use of statistical parameters linear regression) and the effect of the wind turbine operation on the noise level (including low frequencies) and vibration level will be presented.

Martin Meunier

2013-01-01T23:59:59.000Z

263

Comparison of the solar wind energy input to the magnetosphere measured by Wind and Interball-1  

Science Journals Connector (OSTI)

Timely solar wind measurements are indispensable for space weather forecasts and magnetospheric studies, but solar wind variations detected by a distant spacecraft might be different from those actually hitting Earth's magnetosphere. To determine how important these differences can be for geophysical applications, we compared energy input to the magnetosphere which was simultaneously measured by the Wind and Interball-1 spacecraft at various distances from the Earth. The percentage of equal (with differences less than 15%) measurements was found to increase from 30% at energies associated with small substorms to 100% for storm-level energies. The degree of the spacecraft separation along the X GSE coordinate and in the YZ GSE plane appeared to be of minor importance within the limits of Wind and Interball-1 orbits.

A.A Petrukovich; S.I Klimov; A Lazarus; R.P Lepping

2001-01-01T23:59:59.000Z

264

ccsd-00000548(version1):18Aug2003 COMMENTS ON "MEASURING THE GRAVITY SPEED BY VLBI"  

E-Print Network [OSTI]

ccsd-00000548(version1):18Aug2003 COMMENTS ON "MEASURING THE GRAVITY SPEED BY VLBI" H. ASADA or alternative gravity theories might suggest that the gravity propagation speed can be different from the light and Fomalont claimed the first measurement of the gravity speed by VLBI. However, the measurement has

Paris-Sud XI, Université de

265

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

266

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

267

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

268

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

269

Comparison of Triton SODAR Data to Meteorological Tower Wind Measurement Data in Hebei Province, China  

SciTech Connect (OSTI)

With the increased interest in remote sensing of wind information in recent years, it is important to determine the reliability and accuracy of new wind measurement technologies if they are to replace or supplement conventional tower-based measurements. In view of this, HydroChina Corporation and the United States National Renewable Energy Laboratory (NREL) conducted a comparative test near a wind farm in Hebei Province, China. We present the results of an analysis characterizing the measurement performance of a state-of-the-art Sound Detection and Ranging (sodar) device when compared to a traditional tower measurement program. NREL performed the initial analysis of a three-month period and sent the results to HydroChina. When another month of data became available, HydroChina and their consultant Beijing Millenium Engineering Software (MLN) repeated NREL's analysis on the complete data set, also adding sensitivity analysis for temperature, humidity, and wind speed (Section 6). This report presents the results of HydroChina's final analysis of the four-month period.

Yuechun, Y.; Jixue, W.; Hongfang, W.; Guimin, L.; Bolin, Y.; Scott, G.; Elliott, D.; Kline, D.

2012-01-01T23:59:59.000Z

270

Measurement of wind set-up on an open coast  

E-Print Network [OSTI]

VI. BIBLIOGRAPHY 48 iii FIGURES 1 Caplen Pier 16 2 Measuring Circuit 17 3 Stillwell Installation 20 4 Onshore Synchro 24 5 Offshore Synchro and Water Level Recorder 24 6 Differential Generator 25 7 Sample Record of Wind, Wind Set-Up, and 39... maximum float lag error of approximately .02 inches. This error, recorded in water stage measurements, will be found in both the inshore and offshore wells; hence, it is absent in set-up measurements, provided the float in the inshore well is 21 also...

Clayton, William Howard

2013-10-04T23:59:59.000Z

271

Analysis of the circular track experiment measuring the one-way speed of light  

E-Print Network [OSTI]

All experiments attempting to verify the invariance of speed of light directly are based on two-way speed measurement. The challenge in one-way speed measurement, the requirement of spatially separated synchronised clocks, can be possibly circumvented by measuring the speed of light travelling in a closed path. An apparent violation of the invariance principle has been recently reported in the first experiment attempting to measure the one-way speed of light utilising this concept. This experiment is reanalysed here. It is found that the results of the experiment can be explained within the framework of relativity, without requiring any violation of the invariance principle.

Evan John Philip

2012-12-07T23:59:59.000Z

272

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

273

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

274

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

275

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

276

Sound beyond the speed of light: Measurement of negative group velocity in an acoustic loop filter  

E-Print Network [OSTI]

Sound beyond the speed of light: Measurement of negative group velocity in an acoustic loop filter of magnitude difference between the speeds of sound and light. © 2007 American Institute of Physics. DOI: 10,2 A central issue is whether the speed of light in vacuum c constituted an upper limit to the group velocity

Robertson, William

277

Bachelor thesis: "Validation of an engineering model of the near wake wind field of wind turbines based on nacelle based lidar measurements"  

E-Print Network [OSTI]

Bachelor thesis: "Validation of an engineering model of the near wake wind field of wind turbines, in an early stage of wind farm layout optimisation and wind turbine loading calculation in wind farms developed/validated indirectly. Mainly, based on power measurements of downstream wind turbines, instead

Peinke, Joachim

278

First measurement of winds in the ionosphere.  

E-Print Network [OSTI]

, a Cornell University professor of electrical engineering, and his colleagues conceive of a very powerful The Arecibo Observatory begins producing data: the first incoher- ent scatter measurements of the ionosphere. We had no rules or precedents. ...These days if you proposed a big project it would take five years

Danforth, Bryan Nicholas

279

Vibration Measurement on Viaduact of Taiwan High Speed Railway  

Science Journals Connector (OSTI)

There were 13 standard spans of variant span length and pier height tested at early stage of Taiwan High Speed Railway’s operation. The test was aimed to verify the actual dynamic responses meeting the design cod...

C. S. Chen; M. H. Chen; C. Y. Wang

2012-01-01T23:59:59.000Z

280

Measuring the Environmental Externalities of Onshore Wind Power  

Science Journals Connector (OSTI)

Abstract This article provides a brief overview of the environmental externalities that are commonly associated with the development of onshore wind-power projects. The article discusses the physical characteristics of an onshore wind farm; the nature of the positive and negative externalities, such as low-carbon electricity generation, low water consumption, noise, visual amenity, wildlife impacts; and land disruption and change. A simple description of surrogate-based and nonmarket-based methods of measuring these externalities is given. Monetary values are also reported.

A. Bergmann

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "measure wind speed" 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

Goniometric measurement of power scattered from wind driven water surfaces  

Science Journals Connector (OSTI)

A recently constructed 11?ft 3?axis semiautomatic underwater goniometer has made possible precision measurement of acoustic power scattered from the statistically stationary wind driven water surface at Yale. Measurements have been made over 180° of azimuth and at several grazing angles. These measurements have been corrected for beam patterns and pulse shape to give a scattering cross section for the surfaces and geometries studied. The results of these measurements indicate that current mathematical models of the scattering process are not able to predict spatial distribution of scattered power in all cases.

J. G. Zornig

1976-01-01T23:59:59.000Z

282

Spatial and temporal distributions of U.S. winds and wind power at 80 m derived from measurements  

E-Print Network [OSTI]

, global warming, air pollution, energy, wind speed Citation: Archer, C. L., and M. Z. Jacobson, Spatial- pollution-related mortality, urban smog, acid deposition, and visibility degradation. Coal mining also: Pollution--urban and regional (0305); 3399 Meteorology and Atmospheric Dynamics: General or miscellaneous

283

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

284

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

285

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

286

On measurement of the isotropy of the speed of light  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

Three experimental concepts investigating possible anisotropy of the speed of light are presented. They are based on i) beam deflection in a 180 degree magnetic arc, ii) narrow resonance production in an electron-positron collider, and iii) the ratio of magnetic moments of an electron and a positron moving in opposite directions.

Wojtsekhowski, Bogdan B. [JLAB

2014-11-01T23:59:59.000Z

287

On measurement of the isotropy of the speed of light  

E-Print Network [OSTI]

Three experimental concepts investigating possible anisotropy of the speed of light are presented. They are based on i) beam deflection in a 180 degree magnetic arc, ii) narrow resonance production in an electron-positron collider, and iii) the ratio of magnetic moments of an electron and a positron moving in opposite directions.

Wojtsekhowski, B

2014-01-01T23:59:59.000Z

288

On measurement of the isotropy of the speed of light  

E-Print Network [OSTI]

Three experimental concepts investigating possible anisotropy of the speed of light are presented. They are based on i) beam deflection in a 180 degree magnetic arc, ii) narrow resonance production in an electron-positron collider, and iii) the ratio of magnetic moments of an electron and a positron moving in opposite directions.

B. Wojtsekhowski

2014-09-22T23:59:59.000Z

289

Wind-wave measurements in a shallow estuary: Trinity Bay, Texas  

E-Print Network [OSTI]

observations and follow the current proposed asymptotic limit to wave growth in shallow depth. The depth range for this empirical formulation is extended from 0.5–2m out to 3.5m. The model does not work for wind speeds less than 1m/s and during rapid wind...

Dupuis, Keith Wade

2009-05-15T23:59:59.000Z

290

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

291

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

292

Speed Meter As a Quantum Nondemolition Measuring Device for Force  

E-Print Network [OSTI]

Quantum noise is an important issue for advanced LIGO. Although it is in principle possible to beat the Standard Quantum Limit (SQL), no practical recipe has been found yet. This paper dicusses quantum noise in the context of speedmeter-a devise monitoring the speed of the testmass. The scheme proposed to overcome SQL in this case might be more practical than the methods based on monitoring position of the testmass.

F. Ya. Khalili; Yu. Levin

1996-03-26T23:59:59.000Z

293

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

294

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

295

Cloud Features and Zonal Wind Measurements of Saturn's Atmosphere as Observed by Cassini/VIMS  

E-Print Network [OSTI]

We present an analysis of data about Saturn's atmosphere from Cassini's Visual and Infrared Mapping Spectrometer (VIMS), focusing on the meteorology of the features seen in the 5-micron spectral window. We present VIMS mosaics and discuss the morphology and general characteristics of the features backlit by Saturn's thermal emission. We have also constructed a zonal wind profile from VIMS feature tracking observation sequences using an automated cloud feature tracker. Comparison with previously constructed profiles from Voyager and Cassini imaging data reveals broad similarities, suggesting minimal vertical shear of the zonal wind. However, areas of apparent wind shear are present in the VIMS zonal wind profile at jet stream cores. In particular, our analysis shows that the equatorial jet reaches speeds exceeding 450 m/s, similar to speeds obtained during the Voyager era. This suggests that recent inferences of relatively slower jet speeds of ~275-375 m/s are confined to the upper troposphere and that the dee...

Choi, David S; Brown, Robert H; 10.1029/2008JE003254

2013-01-01T23:59:59.000Z

296

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

297

Frostbite Theater - Experiments You Can Try at Home! - Measure the Speed of  

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

It's Done - Anti-Gravity Water Trick! It's Done - Anti-Gravity Water Trick! Previous Video (How It's Done - Anti-Gravity Water Trick!) Frostbite Theater Main Index Next Video (Measure the Width of a Hair - With a Laser!) Measure the Width of a Hair - With a Laser! Measure the Speed of Light - With Chocolate! 'C' is for chocolate! 'c' is also the symbol used for the speed of light. Defined as being 299,792,458 meters per second in vacuum, you can take a crack at measuring the ultimate speed using your microwave, a ruler and a bar of chocolate! Yum! [ Show Transcript ] Announcer: Frostbite Theater presents... Cold Cuts! No baloney! Joanna and Steve: Just science! Joanna: Hi! I'm Joanna! Steve: And I'm Steve! Joanna: Today, we're going to show you how to measure the speed of light using your microwave, a ruler and... a bar of chocolate!

298

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

299

High-speed digital holographic interferometry for vibration measurement  

Science Journals Connector (OSTI)

A system based on digital holographic interferometry for the measurement of vibrations is presented. A high-power continuous laser

Pedrini, Giancarlo; Osten, Wolfgang; Gusev, Mikhail E

2006-01-01T23:59:59.000Z

300

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

Note: This page contains sample records for the topic "measure wind speed" 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

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

302

Measures against the adverse impact of natural wind on air-cooled condensers in power plant  

Science Journals Connector (OSTI)

The natural wind plays disadvantageous roles in the operation of air-cooled steam condensers in power plant. It is of use to take various measures against the adverse effect of wind for the performance improvemen...

LiJun Yang; XiaoZe Du; YongPing Yang

2010-05-01T23:59:59.000Z

303

Lidar-Measured Wind Profiles: The Missing Link in the Global Observing System  

Science Journals Connector (OSTI)

The three-dimensional global wind field is the most important remaining measurement needed to accurately assess the dynamics of the atmosphere. Wind information in the tropics, high latitudes, and stratosphere is particularly deficient. Furthermore, only ...

Wayman E. Baker; Robert Atlas; Carla Cardinali; Amy Clement; George D. Emmitt; Bruce M. Gentry; R. Michael Hardesty; Erland Källén; Michael J. Kavaya; Rolf Langland; Zaizhong Ma; Michiko Masutani; Will McCarty; R. Bradley Pierce; Zhaoxia Pu; Lars Peter Riishojgaard; James Ryan; Sara Tucker; Martin Weissmann; James G. Yoe

2014-04-01T23:59:59.000Z

304

Giotto measurements of cometary and solar wind plasma at the Comet Halley bow shock  

Science Journals Connector (OSTI)

... wind measurement takes 500ms and is repeated every two spacecraft spins or 8 s. The solar wind energy range covers one-quarter of the total energy range in 30 steps; the upper ...

A. J. Coates; R. P. Lin; B. Wilken; E. Amata; K. A. Anderson; H. Borg; D. A. Bryant; C. W. Carlson; D. W. Curtis; V. Formisano; K. Jockers; A. D. Johnstone; A. Korth; D. A. Mendis; H. Reme; A. K. Richter; H. Rosenbauer; J. A. Sauvaud; W. Stüdemann; M. F. Thomsen; C. d'Uston; J. D. Winningham

1987-06-11T23:59:59.000Z

305

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

306

Density, Speed of Sound, and Viscosity Measurements of Reference Materials for Biofuels  

Science Journals Connector (OSTI)

Measurements of density, speed of sound, and viscosity have been carried out on liquid certified reference materials for biofuels as a function of temperature at ambient pressure. The samples included anhydrous and hydrated bioethanol and two biodiesel ...

Arno Laesecke; Tara J. Fortin; Jolene D. Splett

2012-02-10T23:59:59.000Z

307

Error analysis of pose measurement from sonic sensors without using speed of sound information  

E-Print Network [OSTI]

Scott Burnett (1) demonstrated the feasibility of using acoustic sensors to locate an object without information about speed of sound. The algorithms of triangulation and pose measurement, which were introduced in his paper to fulfill the goal...

Lai, Chih-Chien

2012-06-07T23:59:59.000Z

308

The Accuracy of Radar Estimates of Ice Terminal Fall Speed from Vertically Pointing Doppler Radar Measurements  

Science Journals Connector (OSTI)

Doppler radar measurements at different frequencies (50 and 2835 MHz) are used to characterize the terminal fall speed of hydrometeors and the vertical air motion in tropical ice clouds and to evaluate statistical methods for retrieving these two ...

Alain Protat; Christopher R. Williams

2011-10-01T23:59:59.000Z

309

Synchrophasor Measurement-Based Wind Plant Inertia Estimation: Preprint  

SciTech Connect (OSTI)

The total inertia stored in all rotating masses that are connected to power systems, such as synchronous generations and induction motors, is an essential force that keeps the system stable after disturbances. To ensure bulk power system stability, there is a need to estimate the equivalent inertia available from a renewable generation plant. An equivalent inertia constant analogous to that of conventional rotating machines can be used to provide a readily understandable metric. This paper explores a method that utilizes synchrophasor measurements to estimate the equivalent inertia that a wind plant provides to the system.

Zhang, Y.; Bank, J.; Wan, Y. H.; Muljadi, E.; Corbus, D.

2013-05-01T23:59:59.000Z

310

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

311

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

312

Proceedings of ICRC 2001: 1488 c Copernicus Gesellschaft 2001 Measuring air shower speeds with the HiRes Fluorescence Detectors  

E-Print Network [OSTI]

Introduction Electromagnetic air showers are known to travel at the speed of light. However, no measurementProceedings of ICRC 2001: 1488 c Copernicus Gesellschaft 2001 ICRC 2001 Measuring air shower speeds the shower is traveling at c. Since speed is not a constraint, it can be measured. The method can be tested

313

HIGH DYNAMIC-RANGE HIGH SPEED LINAC CURRENT MEASUREMENTS  

SciTech Connect (OSTI)

It is desired to measure the linac current of a charged particle beam with a consistent accuracy over a dynamic range of over 120 dB. Conventional current transformers suffer from droop, can be susceptible to electromagnetic interference (EMI), and can be bandwidth limited. A novel detector and electronics were designed to maximize dynamic range of about 120 dB and measure rise-times on the order of 10 nanoseconds.

Deibele, Craig Edmond [ORNL] [ORNL; Curry, Douglas E [ORNL] [ORNL; Dickson, Richard W [ORNL] [ORNL

2012-01-01T23:59:59.000Z

314

Estimating the Wind Resource in Uttarakhand: Comparison of Dynamic Downscaling with Doppler Lidar Wind Measurements  

Broader source: Energy.gov [DOE]

Previous estimates of the wind resources in Uttarakhand, India, suggest minimal wind resources in this region. To explore whether or not the complex terrain in fact provides localized regions of...

315

Estimating the Wind Resource in Uttarakhand: Comparison of Dynamic Downscaling with Doppler Lidar Wind Measurements  

SciTech Connect (OSTI)

Previous estimates of the wind resources in Uttarakhand, India, suggest minimal wind resources in this region. To explore whether or not the complex terrain in fact provides localized regions of wind resource, the authors of this study employed a dynamic down scaling method with the Weather Research and Forecasting model, providing detailed estimates of winds at approximately 1 km resolution in the finest nested simulation.

Lundquist, J. K.; Pukayastha, A.; St. Martin, C.; Newsom, R.

2014-03-01T23:59:59.000Z

316

Resolving Spacecraft Earth-Flyby Anomalies with Measured Light Speed Anisotropy  

E-Print Network [OSTI]

Doppler shift observations of spacecraft, such as Galileo, NEAR, Cassini, Rosetta and MESSENGER in earth flybys, have all revealed unexplained speed `anomalies' - that the doppler-shift determined speeds are inconsistent with expected speeds. Here it is shown that these speed anomalies are not real and are actually the result of using an incorrect relationship between the observed doppler shift and the speed of the spacecraft - a relationship based on the assumption that the speed of light is isotropic in all frames, i.e. invariant. Taking account of the repeatedly measured light-speed anisotropy the anomalies are resolved. The Pioneer 10/11 anomalies are discussed, but not resolved. The spacecraft observations demonstrate again that the speed of light is not invariant, and is isotropic only with respect to a dynamical 3-space. The existing doppler shift data also offers a resource to characterise a new form of gravitational waves, the dynamical 3-space turbulence, that has also been detected by other techniques.

Reginald T. Cahill

2008-03-31T23:59:59.000Z

317

Measurement of Infrasound Emissions from Wind Turbines Dave Pepyne, Michael Zink and Jamyang Tenzin  

E-Print Network [OSTI]

Measurement of Infrasound Emissions from Wind Turbines Dave Pepyne, Michael Zink and Jamyang Tenzin energy has made wind turbine technology a suitable candidate for pollution-free energy. With its great that received many complaints from the residents living near the large wind turbine poles. Many scientists

Mountziaris, T. J.

318

LIDAR measurements of wind turbine wake dyn_amics and comparison with an engineering model  

E-Print Network [OSTI]

LIDAR measurements of wind turbine wake dyn_amics and comparison with an engineering model 1 dynamics, lIre performed at four diameters behind a 95 kW wind turbine. The wake 111eaeasurement technique allows esti111ation of qUClsiinstantancou~ two dimensional wind fields in an area

319

Reconstruction of a wind turbine's endured load spectrum using a short-time load measurement  

E-Print Network [OSTI]

Reconstruction of a wind turbine's endured load spectrum using a short-time load measurement Abstract Wind turbines (WT) are normally designed for a service life (SL) of 20 years. In Germany, over safety. 1 Introduction A wind turbine (WT) is normally designed, tested and certified for a design life

Berlin,Technische Universität

320

Final Map Draft Comparison Report WIND ENERGY RESOURCE MODELING AND MEASUREMENT PROJECT  

E-Print Network [OSTI]

II Final Map Draft Comparison Report #12;WIND ENERGY RESOURCE MODELING AND MEASUREMENT PROJECT Tel: 978-749-9591 Fax: 978-749-9713 mbrower@awstruewind.com August 10, 2004 #12;2 WIND ENERGY RESOURCE issues. 1 Background In Task 2 of the project, five promising areas of the state for wind energy

Note: This page contains sample records for the topic "measure wind speed" 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

Comment on "Measurement of the speed-of-light perturbation of free-fall absolute gravimeters"  

E-Print Network [OSTI]

The paper (Rothleitner et al. 2014 Metrologia 51, L9) reports on the measurement of the speed-of-light perturbation in absolute gravimeters. The conclusion that the perturbation reaches only 2/3 of the commonly accepted value violates the fundamental limitation on the maximum speed of information transfer. The conclusion was deluded by unaccounted parasitic perturbations, some of which are obvious from the report.

Nagornyi, V D

2014-01-01T23:59:59.000Z

322

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

323

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

324

An application of vortex cancellation to vortex generator techniques in low speed wind tunnels  

E-Print Network [OSTI]

'lugs/ft-sec Axial distance between sets of vortex generators root chord lengths /Y Vertical dimension of duct cross section Tube height/Y in. none ~St i t ()i ()2 (), ( )?q Measured at station g 1 Measured at Station 0 8 Upstream srl... TABLE I II BOUNDARY LAYER PROFILE DATA IN THE VICINITY OF A VORTEX FILAMENT AT STATION 0 7 Tube Number I 2 3 4. 5 6 7 8 9 '10 I 2 3 4 5 6 7 8 9 10 I 2 3 4 5 6 7 8 9 10 Ft-Fs in. H 0 1. 31 1. 31 1. 31 I . 26 1. 20...

Mount, Glynn O., Jr

2012-06-07T23:59:59.000Z

325

CWEX (Crop/Wind-Energy Experiment): Measurements of the interaction between crop agriculture and wind power.  

E-Print Network [OSTI]

??The current expansion of wind farms in the U.S. Midwest promotes an alternative renewable energy portfolio to conventional energy sources derived from fossil fuels. The… (more)

Rajewski, Daniel Andrew

2013-01-01T23:59:59.000Z

326

Sound power level measurement of Sheng, a Chinese wind instrument  

Science Journals Connector (OSTI)

Sheng is one of the Chinese traditional wind instruments. But its sound power level has never been carefully measured. In this paper the sound powermeasurements of Sheng were performed for the first time in a reverberation chamber according to ISO standard and Chinese national standard. Two qualified musicians performed on their own instruments in the center of the reverberation chamber. The radiated sound energy and the dynamic ranges of the Sheng were investigated by four channel acoustic measuring equipments. Typical sound power values were obtained through averaging and the results were reported in this paper. It was showed that the mean forte sound power level can reach up to 98dB with a dynamic range of 22.5dB when music scale was performed. The method discussed here is valuable for the sound powermeasurements of other musical instruments. The measurement of the sound power radiated by national musical instruments lays foundations for the investigation into the acoustics of national music halls.

Yue Zhe Zhao; Shuo Xian Wu; Jian Zhen Qiu; Li Ling Wu; Hong Huang

2008-01-01T23:59:59.000Z

327

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

328

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

329

3D Turbulence Measurements Using Three Synchronous Wind Lidars: Validation against Sonic Anemometry  

Science Journals Connector (OSTI)

This paper presents a technique to measure the time series of the three components of the wind vector at a point in space from synchronous measurements of three scanning Doppler wind lidars. Knowing the position of each lidar on the ground and the ...

Fernando Carbajo Fuertes; Giacomo Valerio Iungo; Fernando Porté-Agel

2014-07-01T23:59:59.000Z

330

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

331

Measurement of sound speed vs. depth in South Pole ice: pressure waves and shear waves  

SciTech Connect (OSTI)

We have measured the speed of both pressure waves and shear waves as a function of depth between 80 and 500 m depth in South Pole ice with better than 1% precision. The measurements were made using the South Pole Acoustic Test Setup (SPATS), an array of transmitters and sensors deployed in the ice at the South Pole in order to measure the acoustic properties relevant to acoustic detection of astrophysical neutrinos. The transmitters and sensors use piezoceramics operating at {approx}5-25 kHz. Between 200 m and 500 m depth, the measured profile is consistent with zero variation of the sound speed with depth, resulting in zero refraction, for both pressure and shear waves. We also performed a complementary study featuring an explosive signal propagating vertically from 50 to 2250 m depth, from which we determined a value for the pressure wave speed consistent with that determined for shallower depths, higher frequencies, and horizontal propagation with the SPATS sensors. The sound speed profile presented here can be used to achieve good acoustic source position and emission time reconstruction in general, and neutrino direction and energy reconstruction in particular. The reconstructed quantities could also help separate neutrino signals from background.

IceCube Collaboration; Klein, Spencer

2009-06-04T23:59:59.000Z

332

Errors for Space-Based Doppler Lidar Wind Measurements: Definition, Performance, and Verification  

Science Journals Connector (OSTI)

Verification of space-based wind measurements will be difficult because of the random variations of the atmospheric velocity field over the measurement volume. The definition of accuracy requires a definition of “truth.” For this work, truth is ...

Rod Frehlich

2001-11-01T23:59:59.000Z

333

PTC, ITC, or Cash Grant? Measuring the Value of Stimulus to Wind Power  

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

PTC, ITC, or Cash Grant? Measuring the Value of Stimulus to Wind Power PTC, ITC, or Cash Grant? Measuring the Value of Stimulus to Wind Power Projects in the United States Speaker(s): Mark Bolinger Date: January 26, 2010 - 12:00pm Location: 90-3122 Seminar Host/Point of Contact: Ryan Wiser The financial crisis of 2008/2009 spawned two major stimulus packages in the U.S. that, in combination, have fundamentally reshaped the federal policy landscape for wind power. Most notably, qualifying wind projects can now, for a limited time only, choose either a 30% investment tax credit (ITC) or a 30% cash grant in lieu of the 10-year production tax credit (PTC) that wind has historically received. This presentation analyzes the impact of this newfound choice of federal incentives on wind power development in the U.S., focusing not only on the relative "face value"

334

DEWEK Wind Energy Conference 2012 Category: 4. Simulation models BACKWARD EXTRAPOLATION OF SHORT-TIME MEASUREMENT DATA FOR A REMAINING SERVICE LIFE ESTIMATION OF WIND  

E-Print Network [OSTI]

DEWEK Wind Energy Conference 2012 Category: 4. Simulation models 1 BACKWARD EXTRAPOLATION OF SHORT-TIME MEASUREMENT DATA FOR A REMAINING SERVICE LIFE ESTIMATION OF WIND TURBINES Dipl.-Ing. René Kamieth, Prof. Dr, Germany, Tel.: +49-(0)30-314-23603, Fax: +49-(0)30-314-26131 Summary Wind turbines built in the last

Berlin,Technische Universität

335

On the solar cycle dependence of winds and planetary waves as seen from mid-latitude D1 LF mesopause region wind measurements*  

E-Print Network [OSTI]

mesospheric winds at Saskatoon, Canada, which were measured in 1978 and 1979 during high solar activityOn the solar cycle dependence of winds and planetary waves as seen from mid-latitude D1 LF-term trends and inÂŻuences of solar variability. The response of the prevailing wind to the 11-year solar cycle

Paris-Sud XI, Université de

336

Assessment and Optimization of Lidar Measurement Availability for Wind Turbine Control (Poster)  

SciTech Connect (OSTI)

Integrating Lidar to improve wind turbine controls is a potential breakthrough for reducing the cost of wind energy. By providing undisturbed wind measurements up to 400m in front of the rotor, Lidar may provide an accurate update of the turbine inflow with a preview time of several seconds. Focusing on loads, several studies have evaluated potential reductions using integrated Lidar, either by simulation or full scale field testing.

Scholbrock, F. A.; Fleming, P.; Wright, A.; Davoust, S.; Jehu, A.; Bouillet, M.; Bardon M.; Vercherin, B.

2014-02-01T23:59:59.000Z

337

Galileo Doppler Measurements of the Deep Zonal Winds at Jupiter  

Science Journals Connector (OSTI)

...overmuch of the atmospheric circulation origi...Jupiter. The atmospheric motions *e...narindicative of deep atmospheric processes...associated with a water condensation rs of the altitude...and the wind recovery ostrophic...

David H. Atkinson; James B. Pollack; Alvin Seiff

1996-05-10T23:59:59.000Z

338

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

339

American Wind Energy Association, Denver, May 2005 Uncertainties in Results of Measure-Correlate-Predict Analyses  

E-Print Network [OSTI]

American Wind Energy Association, Denver, May 2005 Uncertainties in Results of Measure Wind Energy Association, Denver, May 2005 Statistical models are then investigated that estimate-Correlate-Predict Analyses Anthony L. Rogers, Ph. D.* John W. Rogers, M.S.** James F. Manwell, Ph. D.* *Renewable Energy

Massachusetts at Amherst, University of

340

Measuring M dwarf Winds with DAZ White Dwarfs  

E-Print Network [OSTI]

Hydrogen atmosphere white dwarfs with metal lines, so-called DAZs, show evidence for ongoing accretion of material onto their surfaces. Some DAZs are known to have unresolved M dwarf companions, which could account for the observed accretion through a stellar wind. I combine observed Ca abundances of the DAZs with information on the orbital separation of their M dwarf companions to infer the mass loss rate of the M dwarfs. I find that for three of the six known DAZs with M dwarf companions, a stellar wind can plausibly explain the observed accretion on the white dwarfs assuming Bondi-Hoyle accretion of solar abundance stellar winds on the order of 10$^{-14}-10^{-16}\\Msun$ yr$^{-1}$. The rest of the sample have companions with orbits $\\gtorder$ 1~AU, and require companion mass loss rates of $> 10^{-11}\\Msun$ yr$^{-1}$. I conclude that there must be an alternative explanation for accretion of material onto DAZs with widely separated companions. The inferred winds for two of the close binaries are orders of magnitude smaller than typically assumed for the angular momentum loss of red dwarf-white dwarf pairs due to magnetic braking from a stellar wind and may seriously affect predictions for the formation rate of CVs with low mass companions.

J. H. Debes

2006-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "measure wind speed" 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

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

342

Lowering the Light Speed Isotropy Limit: European Synchrotron Radiation Facility Measurements  

E-Print Network [OSTI]

The measurement of the Compton edge of the scattered electrons in GRAAL facility in European Synchrotron Radiation Facility (ESRF) in Grenoble with respect to the Cosmic Microwave Background dipole reveals up to 10 sigma variations larger than the statistical errors. We now show that the variations are not due to the frequency variations of the accelerator. The nature of Compton edge variations remains unclear, thus outlining the imperative of dedicated studies of light speed anisotropy.

V. G. Gurzadyan; J. -P. Bocquet; A. Kashin; A. Margarian; O. Bartalini; V. Bellini; M. Castoldi; A. D'Angelo; J. -P. Didelez; R. Di Salvo; A. Fantini; G. Gervino; F. Ghio; B. Girolami; A. Giusa; M. Guidal; E. Hourany; S. Knyazyan; V. Kouznetsov; R. Kunne; A. Lapik; P. Levi Sandri; A. Lleres; S. Mehrabyan; D. Moricciani; V. Nedorezov; C. Perrin; D. Rebreyend; G. Russo; N. Rudnev; C. Schaerf; M. -L. Sperduto; M. -C. Sutera; A. Turinge

2007-01-05T23:59:59.000Z

343

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

344

Wind power resource assessment in complex urban environments: MIT campus case-study using CFD Analysis  

E-Print Network [OSTI]

around buildings. The software model has been used to evaluate the wind energy potential on the campus-site. Comparisons between the measurements and the predicted wind speeds allowed validation of the software results of Technology, 2Meteodyn Objectives Conclusions References [1] TopoWind software, User Manual [2] Wind Resource

345

High-speed height measurement by a light-source-stepping method using a linear LED array  

Science Journals Connector (OSTI)

High-speed height measurement is required in industrial fields for analyzing the behavior of a breaking object, a vibrating object or a rotating object. A shape measurement performed...

Fujigaki, Motoharu; Oura, Yohei; Asai, Daisuke; Murata, Yorinobu

2013-01-01T23:59:59.000Z

346

Abstract--Resolvers are absolute angle transducers that are usually used for position and speed measurement in  

E-Print Network [OSTI]

measurement in permanent magnet motors. An observer that uses the sinusoidal signals of the resolver is fixed on the rotor, and therefore, it rotates jointly with the shaft passing the output windings. Two on the reference winding Uref and along with the angular movement of the motor shaft , the respective voltages

Sontag, Eduardo

347

Ris-PhD-Report Complex Terrain and Wind Lidars  

E-Print Network [OSTI]

calculations over the same terrains. The lidar performance was also simulated with the commercial software WAs;#12;Author: Ferhat Bingöl Title: Complex terrain and wind lidars Division: Wind Energy Division Risø-PhD-52 and the comparison of the measurement data with the flow model outputs showed that the mean wind speed calculated

348

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

349

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

350

Assessment and Optimization of Lidar Measurement Availability for Wind Turbine Control: Preprint  

SciTech Connect (OSTI)

Turbine-mounted lidars provide preview measurements of the incoming wind field. By reducing loads on critical components and increasing the potential power extracted from the wind, the performance of wind turbine controllers can be improved [2]. As a result, integrating a light detection and ranging (lidar) system has the potential to lower the cost of wind energy. This paper presents an evaluation of turbine-mounted lidar availability. Availability is a metric which measures the proportion of time the lidar is producing controller-usable data, and is essential when a wind turbine controller relies on a lidar. To accomplish this, researchers from Avent Lidar Technology and the National Renewable Energy Laboratory first assessed and modeled the effect of extreme atmospheric events. This shows how a multirange lidar delivers measurements for a wide variety of conditions. Second, by using a theoretical approach and conducting an analysis of field feedback, we investigated the effects of the lidar setup on the wind turbine. This helps determine the optimal lidar mounting position at the back of the nacelle, and establishes a relationship between availability, turbine rpm, and lidar sampling time. Lastly, we considered the role of the wind field reconstruction strategies and the turbine controller on the definition and performance of a lidar's measurement availability.

Davoust, S.; Jehu, A.; Bouillet, M.; Bardon, M.; Vercherin, B.; Scholbrock, A.; Fleming, P.; Wright, A.

2014-05-01T23:59:59.000Z

351

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

352

Determination of the pressure at the gas-liquid interface using acoustic speed measurements  

E-Print Network [OSTI]

underestimates this derivative. We can further see that the dPr/d 7r 120 100 Measured values 80 60 40 20 500 1000 1500 2000 2500 8000 3500 Pressul e, Psi;z ? Meas. ~- Phillips ~ 8 eon ~ ll-eon. Fig. 4 ? dPr/dTr in methane vs. pressure 32 value...'c Speed, ft/sec 22 00 2000 Tr = 3. 0 I 800 1600 Tr = 2. 0 1400 Tr = 1. 1 'I 200 0 0. 5 1 1 5 2 2. 5 3 3. 5 4 4. 5 5 5. 5 5 Reduced Pressure ? Publ ~ Gale ~ Publ ~ Calc ~ Pub ~ Ca c Fig. 13 ? Acoustic speed vs. reduced pressure 44 Based...

Heggelund, Dag Gustav

2012-06-07T23:59:59.000Z

353

New models for wind noise measured in a flat surface under turbulent flow.  

Science Journals Connector (OSTI)

We have previously developed models for predicting the power spectral density of the wind noisepressuremeasured in a flat plate outdoors from the measured power spectral density of the turbulence and the measured wind velocity profile above the plate [Yu et al. Proceedings of NCAD 2008 NoiseCon2008?ASME NCAD]. Recently we have corrected an error in the model for the logarithmic profile wind velocity gradient results and have developed an improved integration method. Also we have developed a prediction for arbitrary wind velocity profiles using the previous single exponential model. Typical results comparing our predictions with our measurements are presented and analyzed. A simple algebraic fit to the prediction for the logarithmic profile fit form is also provided for use by others. [Research supported by the U.S. Army TACOM?ARDEC at Picatinny Arsenal NJ.

2009-01-01T23:59:59.000Z

354

The effect of imbalance distribution and measurement locations on critical speeds in a turboprop engine rotor  

E-Print Network [OSTI]

The critical speeds of a turbomachine can be defined as the speeds at which synchronous response to imbalance is maximum (Vance,1988). Identifying the proper placement of critical speeds is very important in the design process of turbomachinery...

Marin, Manuel

2012-06-07T23:59:59.000Z

355

On local and global measurements of the speed of light on rotating platforms  

E-Print Network [OSTI]

The paper shows that, conceptually and operationally, the speed of light as measured locally in the inertial comoving frame of a point on the rim of a rotating disk, is different from the one measured globally for a round trip along the rim, obtained dividing the length of the rim (as measured in the ''relative space'' of the disk) by the time of flight of the light beam (as measured by a clock at rest on the disk). As a consequence, contrary to some recent claims, the anisotropy found in the global value, obtained by the above procedure, in no way conflicts with the local isotropy, and the internal consistency of the special relativity theory remains unchallenged.

G. Rizzi; A. Tartaglia

1999-04-12T23:59:59.000Z

356

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

357

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

358

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

359

High Speed H2O Concentration Measurements Using Absorption Spectroscopy to Monitor Exhaust Gas  

SciTech Connect (OSTI)

This paper demonstrates the potential for fast absorption spectroscopy measurements in diesel-engine exhaust to track H2O concentration transients. Wavelength-agile absorption spectroscopy is an optical technique that measures broadband absorption spectra between 10kHz and 100 MHz. From these measured spectra, gas temperature and absorber concentration can be determined. The Fourier-domain mode-locking (FDML) laser is becoming recognized as one of the most robust and reliable wavelength-agile sources available. H2O concentration measurements during combustion events at crank angle resolved speeds are beneficial for a wide variety of applications, such as product improvements for industry, control and reliability checks for experimental researchers, and measures of fit for numerical simulations. The difficulties associated with measuring diesel exhaust compared to in-cylinder measurements are discussed. A full description of the experimental configuration and data processing is explained. Measurements of engine exhaust H2O transients with 10- s temporal resolution are presented for a range of engine conditions.

Kranendonk, Laura [ORNL; Parks, II, James E [ORNL; Prikhodko, Vitaly Y [ORNL; Partridge Jr, William P [ORNL

2008-01-01T23:59:59.000Z

360

A comparison of measured wind park load histories with the WISPER and WISPERX load spectra  

SciTech Connect (OSTI)

The blade-loading histories from two adjacent Micon 65/13 wind turbines are compared with the variable-amplitude test-loading histories known as the WISPER and WISPERX spectra. These standardized loading sequences were developed from blade flapwise load histories taken from nine different horizontal-axis wind turbines operating under a wide range of conditions in Europe. The subject turbines covered a broad spectrum of rotor diameters, materials, and operating environments. The final loading sequences were developed as a joint effort of thirteen different European organizations. The goal was to develop a meaningful loading standard for horizontal-axis wind turbine blades that represents common interaction effects seen in service. In 1990, NREL made extensive load measurements on two adjacent Micon 65/13 wind turbines in simultaneous operation in the very turbulent environment of a large wind park. Further, before and during the collection of the loads data, comprehensive measurements of the statistics of the turbulent environment were obtained at both the turbines under test and at two other locations within the park. The trend to larger but lighter wind turbine structures has made an understanding of the expected lifetime loading history of paramount importance. Experience in the US has shown that the turbulence-induced loads associated with multi-row wind parks in general are much more severe than for turbines operating individually or within widely spaced environments. Multi-row wind parks are much more common in the US than in Europe. In this paper we report on our results in applying the methodology utilized to develop the WISPER and WISPERX standardized loading sequences using the available data from the Micon turbines. While the intended purpose of the WISPER sequences were not to represent a specific operating environment, we believe the exercise is useful, especially when a turbine design is likely to be installed in a multi-row wind park.

Kelley, N.D.

1995-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "measure wind speed" 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

Air speeds of migrating birds observed by ornithodolite and compared with predictions from flight theory  

Science Journals Connector (OSTI)

...Caerlaverock. Females are lighter than males, which...mean equivalent air speed (17.5 m s1) is...assumptions, in the light of new data. By...statistical analysis to our speed measurements, we...over the ocean for light to moderate winds...1995 Optimal flight speed of birds. Phil...

2013-01-01T23:59:59.000Z

362

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.

363

Photoacoustically Measured Speeds of Sound of Liquid HBO2: On Unlocking the Fuel Potential of Boron  

SciTech Connect (OSTI)

Elucidation of geodynamic, geochemical, and shock induced processes is often limited by challenges to accurately determine molecular fluid equations of state (EOS). High pressure liquid state reactions of carbon species underlie physiochemical mechanisms such as differentiation of planetary interiors, deep carbon sequestration, propellant deflagration, and shock chemistry. Here we introduce a versatile photoacoustic technique developed to measure accurate and precise speeds of sound (SoS) of high pressure molecular fluids and fluid mixtures. SoS of an intermediate boron oxide, HBO{sub 2} are measured up to 0.5 GPa along the 277 C isotherm. A polarized Exponential-6 interatomic potential form, parameterized using our SoS data, enables EOS determinations and corresponding semi-empirical evaluations of > 2000 C thermodynamic states including energy release from bororganic formulations. Our thermochemical model propitiously predicts boronated hydrocarbon shock Hugoniot results.

Bastea, S; Crowhurst, J; Armstrong, M; ., N T

2010-03-24T23:59:59.000Z

364

THE HUYGENS DOPPLER WIND EXPERIMENT Titan Winds Derived from Probe Radio Frequency Measurements  

E-Print Network [OSTI]

Doppler calibrations conducted with simulated Huygens signals uplinked from ground (Probe Relay Tests to the longer free-space propagation distance. Specific secondary science objectives of DWE include measurements

365

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

366

Experimental Investigation of Wind-Forced Drop Stability  

E-Print Network [OSTI]

aluminum (RA = 3.26 micrometers) floor of a tiltable wind tunnel and brought to critical conditions, when the drop begins to run downstream. Various combinations of drop size, inclination angle, and flow speed were employed. A measurement technique capable...

Schmucker, Jason

2012-10-19T23:59:59.000Z

367

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

368

Relationship between speed distribution measures and rural two-lane highway characteristics  

E-Print Network [OSTI]

mandated 55 mph (88. 5 km/h) speed limit, the original design speed of a roadway does not always meet the desired operating speeds of today's drivers. Thus, a design consistency approach has been suggested as an alternative means for ensuring driver... STATISTICS PRELIMINARY ANALYSIS MEAN SPEED REDUCTION ANALYSIS STANDARD DEVIATION DIFFERENCE ANALYSIS . . 80 . 88 . . 91 VII SUMMARY AND CONCLUSIONS 93 CONCLUSIONS . RECOMMENDATIONS 95 97 REFERENCES APPENDIX . . VITA 100 I04 117 LIST...

Collins, Jon Michael

2012-06-07T23:59:59.000Z

369

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

370

Measuring Speed of Gravitational Waves by Observations of Photons and Neutrinos from Compact Binary Mergers and Supernovae  

E-Print Network [OSTI]

Detection of gravitational waves (GW) provides us an opportunity to test general relativity in strong and dynamical regimes of gravity. One of the tests is checking whether GW propagates with the speed of light or not. This test is crucial because the velocity of GW has not ever been directly measured. Propagation speed of a GW can deviate from the speed of light due to the modification of gravity, graviton mass, and the nontrivial spacetime structure such as extra dimensions and quantum gravity effects. Here we report a simple method to measure the propagation speed of a GW by directly comparing arrival times between gravitational waves, and neutrinos from supernovae or photons from short gamma-ray bursts. As a result, we found that the future multimessenger observations of a GW, neutrinos, and photons can test the GW propagation speed with the precision of ~10^{-16} improving the previous suggestions by 8-10 orders of magnitude. We also propose a novel method that distinguishes the true signal due to the deviation of GW propagation speed from the speed of light and the intrinsic time delay of the emission at a source by looking at the redshift dependence.

Atsushi Nishizawa; Takashi Nakamura

2014-06-20T23:59:59.000Z

371

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

372

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

373

Nonsinusoidal electrical measurement accuracy in adjustable-speed motors and drives  

SciTech Connect (OSTI)

Accurate measurements of voltage, current, and power under nonsinusoidal conditions are essential for determining the efficiency of a drive system and performing separation of losses between an adjustable-speed drive (ASD) and an electric motor. That information is invaluable for equipment designers, manufacturers, and users. Three modern power meters and analyzers were tested to determine their accuracy with various nonsinusoidal waveforms applied. The meters were subjected to waveforms that are characteristic to the three most common fractional and integral horsepower ASD technologies, namely, pulsewidth modulation induction, brushless dc, and switched-reluctance drives. The tests were performed under field conditions and in a computer-controlled laboratory environment. The obtained results show that some meters are able to measure accurately electric power at the input to ASD`s. However, the output power of ASD`s for brushless dc and switched-reluctance technology was not measured with acceptable accuracy by any of the tested meters. Possible reasons of meters inaccuracies and suggestions for performance improvement are presented. Conclusions on the present state of ASD electric power measurements and recommendations for further research are given.

Domijan, A. [Univ. of Florida, Gainesville, FL (United States)] [Univ. of Florida, Gainesville, FL (United States); Czarkowski, D. [Polytechnic Univ., Brooklyn, NY (United States). Dept. of Electrical Engineering] [Polytechnic Univ., Brooklyn, NY (United States). Dept. of Electrical Engineering; Johnson, J.H. [J.H. Johnson Associates, Inc., Tipp City, OH (United States)] [J.H. Johnson Associates, Inc., Tipp City, OH (United States)

1998-11-01T23:59:59.000Z

374

Automation of a high-speed imaging setup for differential viscosity measurements  

SciTech Connect (OSTI)

We present the automation of a setup previously used to assess the viscosity of pleural effusion samples and discriminate between transudates and exudates, an important first step in clinical diagnostics. The presented automation includes the design, testing, and characterization of a vacuum-actuated loading station that handles the 2 mm glass spheres used as sensors, as well as the engineering of electronic Printed Circuit Board (PCB) incorporating a microcontroller and their synchronization with a commercial high-speed camera operating at 10 000 fps. The hereby work therefore focuses on the instrumentation-related automation efforts as the general method and clinical application have been reported earlier [Hurth et al., J. Appl. Phys. 110, 034701 (2011)]. In addition, we validate the performance of the automated setup with the calibration for viscosity measurements using water/glycerol standard solutions and the determination of the viscosity of an “unknown” solution of hydroxyethyl cellulose.

Hurth, C.; Duane, B.; Whitfield, D.; Smith, S.; Nordquist, A.; Zenhausern, F. [Center for Applied Nanobioscience and Medicine, The University of Arizona College of Medicine, 425 N 5th Street, Phoenix, Arizona 85004 (United States)] [Center for Applied Nanobioscience and Medicine, The University of Arizona College of Medicine, 425 N 5th Street, Phoenix, Arizona 85004 (United States)

2013-12-28T23:59:59.000Z

375

On-vehicle emission measurement of a light-duty diesel van at various speeds at high altitude  

Science Journals Connector (OSTI)

Abstract As part of the research on the relationship between the speed of a vehicle operating at high altitude and its contaminant emissions, an on-vehicle emission measurement of a light-duty diesel van at the altitudes of 1000 m, 2400 m and 3200 m was conducted. The test vehicle was a 2.8 L turbocharged diesel Ford Transit. Its settings were consistent in all experiments. Regulated gaseous emissions, including CO, HC and NOx, together with particulate matter was measured at nine speeds ranged from 10 km h?1 to 90 km h?1 with 10 km h?1 intervals settings. At each speed, measurement lasted for at least 120 s to ensure the sufficiency and reliability of the collected data. The results demonstrated that at all altitudes, CO and HC emissions decreased as the vehicle speed increased. However both \\{NOx\\} and PM increased with vehicle speed. In terms of the effects of altitude, an increase in CO, HC and PM was observed with the rising of altitude at each vehicle speed. \\{NOx\\} behaved different: emission of \\{NOx\\} initially increased as the vehicle was raised from 1000 m to 2400 m, but it decreased when the vehicle was further elevated to 3200 m.

Xin Wang; Hang Yin; Yunshan Ge; Linxiao Yu; Zhenxian Xu; Chenglei Yu; Xuejiao Shi; Hongkun Liu

2013-01-01T23:59:59.000Z

376

Vibration measurement of a miniature component by high-speed image-plane digital holographic microscopy  

SciTech Connect (OSTI)

Measuring deformation of vibrating specimens whose dimensions are in the submillimeter range introduces a number of difficulties using laser interferometry. Normal interferometry is not suitable because of a phase ambiguity problem. In addition, the noise effect is much more serious in the measurement of small objects because a high-magnification lens is used. We present a method for full-field measurement of displacement, velocity, and acceleration of a vibrating miniature object based on image-plane digital holographic microscopy. A miniature cantilever beam is excited by a piezoelectric transducer stage with a sinusoidal configuration. A sequence of digital holograms is captured using a high-speed digital holographic microscope. Windowed Fourier analysis is applied in the spatial and spatiotemporal domains to extract the displacement, velocity and acceleration. The result shows that a combination of image-plane digital holographic microscopy and windowed Fourier analyses can be used to study vibration without encountering a phase ambiguity problem, and one can obtain instantaneous kinematic parameters on each point.

Fu Yu; Shi Hongjian; Miao Hong

2009-04-10T23:59:59.000Z

377

ISET-Wind-Index Assessment of the Annual Available Wind Energy  

E-Print Network [OSTI]

Particularly in years with wind speeds that are clearly below average, dissatisfaction of operators and even liquidity problems are sparked through the unexpected low annual power production. An objective standard for the evaluation of the respective “wind year ” is required for the internal estimation of the performance of wind farms, and for justification to share owners and banks. The annual wind conditions are composed from such a multitude of meteorological situations, differing from location to location, that the available wind energy at every individual location develops totally differently. A single code is therefore not sufficient to describe the “wind year ” in Germany and, moreover, the evaluation of annual available wind energy must be carried out separately for the smallest areas possible. With the support of the Gothaer Rückversicherungen AG, a procedure has been developed at ISET which provides the proportion of the respective annual available wind energy, in relation to the long-term average available wind energy, for each 10 km x 10 km sized plan area in Germany. This amount, the ISET-Wind-Index, is founded on wind measurements at locations that are typical for wind energy use and therefore presents an objective standard. The measurement grid is part of the “Scientific Measurement and Evaluation Programme ” (WMEP), which accompanies the “250 MW Wind ” project of the German Federal Ministry for Economy and Labour. The ISET-Wind-Index, which will be regularly updated, provides an objective standard for the estimation of annual available

Berthold Hahn; Kurt Rohrig

2003-01-01T23:59:59.000Z

378

A Low-Cost System for Measuring Horizontal Winds from Single-Engine Aircraft  

Science Journals Connector (OSTI)

The implementation and accuracy of a low-rate (~1 Hz) horizontal wind measurement system is described for a fixed-wing aircraft without modification to the airframe. The system is based on a global positioning system (GPS) compass that provides ...

Stephen A. Conley; Ian C. Faloona; Donald H. Lenschow; Anna Karion; Colm Sweeney

2014-06-01T23:59:59.000Z

379

Cloud features and zonal wind measurements of Saturn's atmosphere as observed by Cassini/VIMS  

E-Print Network [OSTI]

Cloud features and zonal wind measurements of Saturn's atmosphere as observed by Cassini/VIMS D. S Cassini's Visual and Infrared Mapping Spectrometer (VIMS), focusing on the meteorology of the features seen in the 5 mm spectral window. We present VIMS mosaics and discuss the morphology and general

Choi, David S.

380

On the Use of QuikSCAT Scatterometer Measurements of Surface Winds for Marine Weather Prediction  

E-Print Network [OSTI]

and ECMWF global numerical weather prediction models considerably underestimated the spatial variability Centre for Medium-Range Weather Forecasts (ECMWF) global numerical weather prediction (NWP) modelsOn the Use of QuikSCAT Scatterometer Measurements of Surface Winds for Marine Weather Prediction

Kurapov, Alexander

Note: This page contains sample records for the topic "measure wind speed" 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

European Wind Energy Conference 2007 Milan Measurement based analysis of active and reactive power  

E-Print Network [OSTI]

European Wind Energy Conference 2007 ­ Milan 1 Measurement based analysis of active and reactive to the network through distribution systems. Because the production units, the distribution systems units will cover consumption in the vicinity. This can contribute to the reduction of the system losses

382

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...

383

Powering Up With Space-Time Wind Forecasting Amanda S. HERING and Marc G. GENTON  

E-Print Network [OSTI]

Powering Up With Space-Time Wind Forecasting Amanda S. HERING and Marc G. GENTON The technology to harvest electricity from wind energy is now advanced enough to make entire cities powered by it a reality be more realistically assessed with a loss measure that depends upon the power curve relating wind speed

Genton, Marc G.

384

Nanogenerator as an active sensor for vortex capture and ambient wind-velocity detection  

E-Print Network [OSTI]

and mechanical (wind, water flow, vibration, friction and body movement) energies are common in the ambientNanogenerator as an active sensor for vortex capture and ambient wind-velocity detection Rui Zhang principle, ambient wind-speed measurements with the NG are demonstrated. Due to the simple structure, high

Wang, Zhong L.

385

High Resolution Atmospheric Modeling for Wind Energy Applications  

SciTech Connect (OSTI)

The ability of the WRF atmospheric model to forecast wind speed over the Nysted wind park was investigated as a function of time. It was found that in the time period we considered (August 1-19, 2008), the model is able to predict wind speeds reasonably accurately for 48 hours ahead, but that its forecast skill deteriorates rapidly after 48 hours. In addition, a preliminary analysis was carried out to investigate the impact of vertical grid resolution on the forecast skill. Our preliminary finding is that increasing vertical grid resolution does not have a significant impact on the forecast skill of the WRF model over Nysted wind park during the period we considered. Additional simulations during this period, as well as during other time periods, will be run in order to validate the results presented here. Wind speed is a difficult parameter to forecast due the interaction of large and small length scale forcing. To accurately forecast the wind speed at a given location, the model must correctly forecast the movement and strength of synoptic systems, as well as the local influence of topography / land use on the wind speed. For example, small deviations in the forecast track or strength of a large-scale low pressure system can result in significant forecast errors for local wind speeds. The purpose of this study is to provide a preliminary baseline of a high-resolution limited area model forecast performance against observations from the Nysted wind park. Validating the numerical weather prediction model performance for past forecasts will give a reasonable measure of expected forecast skill over the Nysted wind park. Also, since the Nysted Wind Park is over water and some distance from the influence of terrain, the impact of high vertical grid spacing for wind speed forecast skill will also be investigated.

Simpson, M; Bulaevskaya, V; Glascoe, L; Singer, M

2010-03-18T23:59:59.000Z

386

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

387

Measurements and analysis of turbulent consumption speeds of H2/CO mixtures Prabhakar Venkateswaran a,  

E-Print Network [OSTI]

Available online 9 February 2011 Keywords: Syngas Hydrogen Global consumption speeds Turbulent flame speed since they are the primary constitu- ents of syngas fuels. Data are reported at mean flow velocities than SL,0. Ă? 2011 The Combustion Institute. Published by Elsevier Inc. All rights reserved. 1

Lieuwen, Timothy C.

388

Performance Indicators of Wind Energy Production  

E-Print Network [OSTI]

Modeling wind speed is one of the key element when dealing with the production of energy through wind turbines. A good model can be used for forecasting, site evaluation, turbines design and many other purposes. In this work we are interested in the analysis of the future financial cash flows generated by selling the electrical energy produced. We apply an indexed semi-Markov model of wind speed that has been shown, in previous investigation, to reproduce accurately the statistical behavior of wind speed. The model is applied to the evaluation of financial indicators like the Internal Rate of Return, semi-Elasticity and relative Convexity that are widely used for the assessment of the profitability of an investment and for the measurement and analysis of interest rate risk. We compare the computation of these indicators for real and synthetic data. Moreover, we propose a new indicator that can be used to compare the degree of utilization of different power plants.

D'Amico, G; Prattico, F

2015-01-01T23:59:59.000Z

389

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

390

Offshore wind project surges ahead in South Carolina | Department of Energy  

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

Offshore wind project surges ahead in South Carolina Offshore wind project surges ahead in South Carolina Offshore wind project surges ahead in South Carolina October 12, 2010 - 10:00am Addthis Researchers pull buoys from waters off South Carolina's coast. The buoys collected wind speed measurements for the past year. | Photo courtesy of the Center for Marine and Wetland Studies Researchers pull buoys from waters off South Carolina's coast. The buoys collected wind speed measurements for the past year. | Photo courtesy of the Center for Marine and Wetland Studies Stephen Graff Former Writer & editor for Energy Empowers, EERE 6 buoys collected wind speeds off South Carolina coast Data collected helps determine possible location for an offshore wind farm DOE funded research for early stage of project In the parking lot of Coastal Carolina University's Center for Marine and

391

Measuring Speed of Gravitational Waves by Observations of Photons and Neutrinos from Compact Binary Mergers and Supernovae  

E-Print Network [OSTI]

Detection of gravitational waves (GW) provides us an opportunity to test general relativity in strong and dynamical regimes of gravity. One of the tests is checking whether GW propagates with the speed of light or not. This test is crucial because the velocity of GW has not ever been measured. Propagation speed of a GW can deviate from the speed of light due to the modification of gravity, graviton mass, and the nontrivial spacetime structure such as extra dimensions and quantum gravity effects. Here we report a simple method to measure the propagation speed of a GW by directly comparing arrival times between gravitational waves, and neutrinos from supernovae or photons from short gamma-ray bursts. As a result, we found that the future multimessenger observations of a GW, neutrinos, and photons can test the GW propagation speed with the precision of ~10^{-16}, improving the previous suggestions by 8-10 orders of magnitude. We also propose a novel method that distinguishes the true signal due to the deviation ...

Nishizawa, Atsushi

2014-01-01T23:59:59.000Z

392

Amplitude modulation of wind turbine noise  

E-Print Network [OSTI]

Due to swish and thump amplitude modulation, the noise of wind turbines cause more annoyance than other environmental noise of the same average level. The wind shear accounts for the thump modulation (van den Berg effect). Making use of the wind speed measurements at the hub height, as well as at the top and the bottom of the rotor disc (Fig.1), the non-standard wind profile is applied. It causes variations in the A-weighted sound pressure level, LpA. The difference between the maximum and minimum of LpA characterizes thump modulation (Fig.2).

Makarewicz, Rufin

2013-01-01T23:59:59.000Z

393

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.

394

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

395

Study of stellar wind energy flux: from the Sun to Beltegeuse  

Science Journals Connector (OSTI)

This study examines the solar wind energy flux from 17 years of Ulysses measurements at different heliolatitudes completed by multi?instrument observations. The solar wind energy flux is almost constant nearly independant on wind speed and solar activity. We then compare the energy flux of the Sun to the stellar wind fluxes in addition to the luminosity fluxes from young stars to supergiants. A share processus of origin and acceleration of the main?sequence stars and cool giants’ winds is suggested. T?Tauri stars’winds show a possible result of an accretion powered wind.

G. Le Chat; N. Meyer?Vernet; K. Issautier

2009-01-01T23:59:59.000Z

396

A high-speed data acquisition system to measure low-level current from self-powered flux detectors in CANDU nuclear reactors  

E-Print Network [OSTI]

A high-speed data acquisition system to measure low-level current from self-powered flux detectors in CANDU nuclear reactors

Lawrence, C B

1982-01-01T23:59:59.000Z

397

Measurement of sound speed vs. depth in South Pole ice: pressure waves and shear waves  

E-Print Network [OSTI]

Price, Attenuation of acoustic waves in glacial ice and saltacoustics, South Pole, sound speed, pressure waves,shear waves PACS: 47.35.De, 47.35.Rs, 62.65. +k, 92.40.Vq,

Klein, Spencer

2010-01-01T23:59:59.000Z

398

Measurements on ferroelectric liquid-crystal spatial light modulators: contrast ratio and speed  

Science Journals Connector (OSTI)

The contrast ratio and the speed of a 16 × 16 electrically addressed spatial light modulator, composed of a ferroelectric liquid-crystal layer on top of a VLSI silicon backplane, are...

Collings, N; Gourlay, J; Vass, D G; White, H J; Stace, C; Proudley, G M

1995-01-01T23:59:59.000Z

399

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

400

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

Note: This page contains sample records for the topic "measure wind speed" 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

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...

402

Indirect Measurement Of Nitrogen In A Multi-Component Gas By Measuring The Speed Of Sound At Two States Of The Gas.  

DOE Patents [OSTI]

A methods of indirectly measuring the nitrogen concentration in a gas mixture. The molecular weight of the gas is modeled as a function of the speed of sound in the gas, the diluent concentrations in the gas, and constant values, resulting in a model equation. Regression analysis is used to calculate the constant values, which can then be substituted into the model equation. If the speed of sound in the gas is measured at two states and diluent concentrations other than nitrogen (typically carbon dioxide) are known, two equations for molecular weight can be equated and solved for the nitrogen concentration in the gas mixture.

Morrow, Thomas B. (San Antonio, TX); Behring, II, Kendricks A. (Torrance, CA)

2004-10-12T23:59:59.000Z

403

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

404

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 !

405

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

406

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

407

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

408

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

409

Measurement of the speed of sound by observation of the Mach cones in a complex plasma under microgravity conditions  

E-Print Network [OSTI]

We report the first observation of the Mach cones excited by a larger microparticle (projectile) moving through a cloud of smaller microparticles (dust) in a complex plasma with neon as a buffer gas under microgravity conditions. A collective motion of the dust particles occurs as propagation of the contact discontinuity. The corresponding speed of sound was measured by a special method of the Mach cone visualization. The measurement results are fully incompatible with the theory of ion acoustic waves. We explore the analogy between a strongly coupled Coulomb system and a solid. A scaling law for the complex plasma makes it possible to derive a theoretical estimate for the speed of sound, which is in a reasonable agreement with the experiments in strongly coupled complex plasmas.

Zhukhovitskii, D I; Molotkov, V I; Lipaev, A M; Naumkin, V N; Thomas, H M; Ivlev, A V; Schwabe, M; Morfill, G E

2014-01-01T23:59:59.000Z

410

Influence of non-Gaussian wind characteristics on wind turbine extreme response  

Science Journals Connector (OSTI)

Abstract The wind turbulence inflows specified in current wind turbine design standards and turbine response simulation tools are usually modeled as stationary random Gaussian processes. Field measurement data, however, suggest that wind turbulence in complex terrain exhibits non-Gaussian characteristics. This study presents a comprehensive investigation on extreme response of operational and parked wind turbines to non-Gaussian wind field. The non-Gaussian wind fields with specified non-Gaussian statistics and power spectral characteristics are generated using translation process theory and spectral representation method. The wind turbine response time histories at each wind speed bin are simulated. The turbine response statistical moments influenced by the non-Gaussian wind inflow are examined. The extreme response distributions conditional on wind speeds are determined from the simulation data using global maxima method and random process model method. The overall extreme response distribution is then calculated by further integrating the distribution of mean wind speed, which is used to quantify the extreme responses with various mean recurrence intervals (MRIs). The results showed that the non-Gaussian characteristics of wind inflows can result in noticeably larger extremes of blade root edgewise and tower base fore-aft bending moments of operational turbine, and blade root flapwise bending moment of parked turbine. The responses with larger \\{MRIs\\} are more sensitive to the non-Gaussian characteristics of wind inflows. The responses of parked turbine are less sensitive to non-Gaussian, especially, the tower base side-to-side bending moment is almost not affected by non-Gaussian. New insights on the determination of extreme response distribution from random process method are also presented focusing on a better modeling of the response distribution tail.

Kuangmin Gong; Xinzhong Chen

2014-01-01T23:59:59.000Z

411

The PNL single-tower measurement model of rotationally sampled turbulent wind, with user's guide for STRS2PC  

SciTech Connect (OSTI)

This report describes a single-tower rotationally sampled wind model, STRS-2, that approximates a set of time series of turbulent wind experienced by individual points rotating in circles in a crosswind plane using measurements from anemometers arrayed vertically along a single line. The purposes of the model are (1) to use turbulence measurements made economically from conventional single-tower arrays of anemometers, (2) to incorporate measures characteristics of the wind at specific sites under consideration for operation of wind turbines, spanning the height range if interest, and (3) to estimate the unmeasured turbulence characteristics in the crosswind plane that spans the disk of the rotor blades. 17 refs., 15 figs., 5 tabs.

Connell, J.R.; Morris, V.R.; Powell, D.C.; Gower, G.L.

1988-06-01T23:59:59.000Z

412

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

413

Upper Air Wind Measurements by Weather Radar Iwan Holleman, Henk Benschop, and Jitze van der Meulen  

E-Print Network [OSTI]

or assimilated into numerical weather prediction (NWP) models. Un- der the assumption of a linear wind field background statistics of the weather radar wind profiles against the Hirlam NWP model are at least as good of the VVP wind profiles against the Hirlam NWP model demonstrate the high quality of weather radar wind

Stoffelen, Ad

414

The status of wind energy development in Tanzania  

Science Journals Connector (OSTI)

Wind energy development in Tanzania started about 3 decades ago when some windmills were installed at several locations in the country to pump water for human and animal consumption and in a few cases for irrigation. There were some attempts to manufacture the windmills locally but these were never successful. In 1980 there were some attempts to generate electricity from wind but these also were unsuccessful. The analysed wind speed data revealed that the wind energy potential in Tanzania is fairly high. The analysis also showed that the windy season coincides with the dry season. The available wind energy at one prospective site called if harvested for the purpose of electricity generation could help to alleviate the shortage of hydroelectricity that prevails during the dry season. Wind energy experts are involved in analysing the available wind speed data and also measuring wind speed in small intervals of time at the sites that are believed to have high wind energy potential. It is also planned to draw a wind map for Tanzania.

R R M Kainkwa

2002-01-01T23:59:59.000Z

415

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

416

Wind Monitoring Report for Fort Wainwright's Donnelly Training Area  

SciTech Connect (OSTI)

Using the wind data collected at a location in Fort Wainwright’s Donnelly Training Area (DTA) near the Cold Regions Test Center (CRTC) test track, Pacific Northwest National Laboratory (PNNL) estimated the gross and net energy productions that proposed turbine models would have produced exposed to the wind resource measured at the meteorological tower (met tower) location during the year of measurement. Calculations are based on the proposed turbine models’ standard atmospheric conditions power curves, the annual average wind speeds, wind shear estimates, and standard industry assumptions.

Orrell, Alice C.; Dixon, Douglas R.

2011-01-18T23:59:59.000Z

417

Technological Advances in Hydraulic Drive Trains for Wind Turbines  

Science Journals Connector (OSTI)

The reliability of frequency converters is a major concern for wind turbines. ChapDrive AS has built and tested a hydraulic drive train for variable speed wind turbines which includes a synchronous generator that is connected to the grid without the use of a frequency converter. The hydraulic drive train consists of a hydraulic pump, a variable displacement hydraulic motor, and a synchronous generator, which enables rotor speed control while maintaining synchronous speed of the generator. It has been proven that the hydraulic drive train and the ChapDrive Control system are able to absorb fluctuations in the wind speed and maintain a constant power output without the use of frequency converters. The hydraulic drive train and the ChapDrive Control system has been modeled analytically and compared to measurements, demonstrating a good agreement between simulations and measurements.

K.E.Thomsen; O.G. Dahlhaug; M.O.K. Niss; S.K. Haugset

2012-01-01T23:59:59.000Z

418

Can One-Way Light Speed be Measured? Comment on E. D. Greaves et al., Am. J. Phys. 77(10), 894-896 (2009)  

E-Print Network [OSTI]

The convention dependence of one-way light speed is explained in a manner accessible to those unaccustomed to the concept. That logic is used to challenge the claim by Greaves et al that their experiment detected one-way light speed. The reason for the result obtained is then presented and followed by an explanation of why the Romer experiment did not measure a convention independent one-way light speed.

Robert D. Klauber

2010-03-25T23:59:59.000Z

419

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

420

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

Note: This page contains sample records for the topic "measure wind speed" 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

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

422

Eddy correlation measurements of the air/sea flux of dimethylsulfide over the North Pacific Ocean  

E-Print Network [OSTI]

the fluctuations in vertical wind speed and the fluctuationslabeled DMS standard and vertical wind speed. The isotope is

Marandino, C. A; De Bruyn, W. J; Miller, S. D; Saltzman, E. S

2007-01-01T23:59:59.000Z

423

Inflow Characterization and Aerodynamics Measurements on a SWT-2.3-101 Wind Turbine: Preprint  

SciTech Connect (OSTI)

Post processing techniques for aerodynamic data acquired from a Siemens SWT-2.3-101 turbine have been developed and applied in this paper. The turbine is installed at the National Wind Technology Center (NWTC) as part of Cooperative Research And Development Agreement between Siemens Wind Power and the National Renewable Energy Laboratory (NREL) under U.S. Department of Energy (DOE) sponsorship. The results indicate that the use of these corrections is essential for accurate analysis of the data. An example of local inflow angles, velocities, and inflow velocity over the rotor plane derived from measurements from a 5-hole probe is also presented. Finally the pressure measurements are used to characterize unsteady phenomenon, namely, rotational augmentation and dynamic stall on an inboard station. The results show that the rotational augmentation can considerably increase the attached flow regime compared to the 2D CFD results. The dynamic stall event was seen to significantly delay the stall. Furthermore, the nondimensionalized vortex convection derived from the dynamic stall event was found to agree well with results from others studies.

Medina, P.; Singh, M.; Johansen, J.; Jove, A.; Fingersh, L.; Schreck, S.

2012-01-01T23:59:59.000Z

424

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

425

Development and Validation of an Aeroelastic Model of a Small Furling Wind Turbine: Preprint  

SciTech Connect (OSTI)

Small wind turbines often use some form of furling (yawing and/or tilting out of the wind) to protect against excessive power generation and rotor speeds in high winds.The verification study demonstrated the correct implementation of FAST's furling dynamics. During validation, the model tends to predict mean rotor speeds higher than measured in spite of the fact that the mean furl motion and rotor thrust are predicted quite accurately. This work has culminated with an enhanced version of FAST that should prove to be a valuable asset to designers of small wind turbines.

Jonkman, J. M.; Hansen, A. C.

2004-12-01T23:59:59.000Z

426

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

427

Characterization of the SUMO Turbulence Measurement System for Wind Turbine Wake Assessment  

Science Journals Connector (OSTI)

Abstract The remotely piloted aircraft system (RPAS) SUMO (Small Unmanned Meteorological Observer) has been equipped with a miniaturized 5-hole probe sensor system for measurement of the 3-dimensional flow vector with a temporal resolution of 100 Hz. Due to its’ weight and size this system is particularly well suited for operations in the vicinity of wind turbines. To qualify for full scale measurements in turbine wakes the system has been characterized by several laboratory and field tests described in this study. A wind tunnel test against a hot-wire anemometer shows the capability of the 5-hole probe to react to turbulence in the same manner as the hot-wire system. The resulting spectra from the two platforms show in general good agreement for both laminar and turbulent flows. The 5-hole probe system is able to resolve turbulence up to frequencies around 20 ? 30 Hz when using a tubing length of 15 cm between the probe and the pressure transducers. In addition, an environmental parallel test against to two sonic anemometers mounted on the roof-top of a car was performed at Bergen airport Flesland. Despite several issues with the self-made and low-cost experimental setup, important system characteristics could be tested and verified. In particular the velocity spectral components of the sonic anemometer system and the 5-hole probe are in close resemblance to each other. This is at least a strong indication that the 5-hole probe is suitable for atmospheric turbulence measurements onboard the RPAS SUMO platform.

Line Bĺserud; Martin Flügge; Anak Bhandari; Joachim Reuder

2014-01-01T23:59:59.000Z

428

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

429

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

430

Vibration measurement of a miniature component by high-speed image-plane digital holographic microscopy  

Science Journals Connector (OSTI)

Measuring deformation of vibrating specimens whose dimensions are in the submillimeter range introduces a number of difficulties using laser interferometry. Normal interferometry is...

Fu, Yu; Shi, Hongjian; Miao, Hong

2009-01-01T23:59:59.000Z

431

Electronics Based Innovation In A Niche Market: Distances Measured By The Speed Of Light.  

E-Print Network [OSTI]

??The purpose of this study is to document the development of an accurate, affordable, reliable machine to perform the relatively long distance measurements routinely made… (more)

Murphy, James S.

2004-01-01T23:59:59.000Z

432

Development of a New Flame Speed Vessel to Measure the Effect of Steam Dilution on Laminar Flame Speeds of Syngas Fuel Blends at Elevated Pressures and Temperatures  

E-Print Network [OSTI]

, including the H2O. .............................................................................................................................................. 35 Table 6 Standard L9 DOE test matrix for four factors (A-D) at three levels (1-3) (Ross... sensitivity analysis based on the maximum difference between the averaged laminar flame speeds at each DOE level (1, 2, or 3) for four oxygen equivalence ratios. ...................................................................................... 41 Table...

Krejci, Michael

2012-07-16T23:59:59.000Z

433

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

434

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....

435

Wind farm noise  

Science Journals Connector (OSTI)

Arrays of small wind turbines recently coined as “wind farms” offer several advantages over single larger wind turbines producing the same electrical power. Noise source characteristics of wind farms are also different from those associated with a single wind turbine. One?third octave band noise measurements from 2 Hz to 10 kHz have been made and will be compared to measurements of noise produced by a single large wind turbine. [J. R. Balombin Technical Memorandum 81486.

Gregory C. Tocci; Brion G. Koning

1981-01-01T23:59:59.000Z

436

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

437

Self Consistent Models of the Solar Wind  

E-Print Network [OSTI]

The origins of the hot solar corona and the supersonically expanding solar wind are still the subject of much debate. This paper summarizes some of the essential ingredients of realistic and self-consistent models of solar wind acceleration. It also outlines the major issues in the recent debate over what physical processes dominate the mass, momentum, and energy balance in the accelerating wind. A key obstacle in the way of producing realistic simulations of the Sun-heliosphere system is the lack of a physically motivated way of specifying the coronal heating rate. Recent models that assume the energy comes from Alfven waves that are partially reflected, and then dissipated by magnetohydrodynamic turbulence, have been found to reproduce many of the observed features of the solar wind. This paper discusses results from these models, including detailed comparisons with measured plasma properties as a function of solar wind speed. Some suggestions are also given for future work that could answer the many remain...

Cranmer, Steven R

2010-01-01T23:59:59.000Z

438

Session: Poster Session + Poster Award + Scientific Award + Excellent young wind doctor award (PO.206) Track: Technical  

E-Print Network [OSTI]

Session: Poster Session + Poster Award + Scientific Award + Excellent young wind doctor award (PO the erection of masts equipped with calibrated cup or sonic anemometers. In order to reduce costs associated, the mean horizontal wind speed measured with a LiDAR shows very good comparison to cup anemometers. However

439

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

440

Photoacoustically Measured Speeds of Sound and the Equation of State of HBO2: On Understanding Detonation with Boron Fuel  

SciTech Connect (OSTI)

Elucidation of geodynamic, geochemical, and shock induced processes is limited by challenges to accurately determine molecular fluid equations of state (EOS). High pressure liquid state reactions of carbon species underlie physiochemical mechanisms such as differentiation of planetary interiors, deep carbon sequestration, propellant deflagration, and shock chemistry. In this proceedings paper we introduce a versatile photoacoustic technique developed to measure accurate and precise speeds of sound (SoS) of high pressure molecular fluids and fluid mixtures. SoS of an intermediate boron oxide, HBO{sub 2} are measured up to 0.5 GPa along the 277 C isotherm. A polarized exponential-6 interatomic potential form, parameterized using our SoS data, enables EOS determinations and corresponding semi-empirical evaluations of >2000 C thermodynamic states including energy release from bororganic formulations. Our thermochemical model propitiously predicts boronated hydrocarbon shock Hugoniot results.

Zaug, J M; Bastea, S; Crowhurst, J; Armstrong, M; Fried, L; Teslich, N

2010-03-09T23:59:59.000Z

Note: This page contains sample records for the topic "measure wind speed" 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

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...

442

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

443

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

444

Magnetized Gas Clouds can Survive Acceleration by a Hot Wind  

E-Print Network [OSTI]

We present three-dimensional magnetohydrodynamic simulations of magnetized gas clouds accelerated by hot winds. We initialize gas clouds with tangled internal magnetic fields and show that this field suppresses the disruption of the cloud: rather than mixing into the hot wind as found in hydrodynamic simulations, cloud fragments end up co-moving and in pressure equilibrium with their surroundings. We also show that a magnetic field in the hot wind enhances the drag force on the cloud by a factor ~(1+v_A^2/v_wind^2)$, where v_A is the Alfven speed in the wind and v_wind measures the relative speed between the cloud and the wind. We apply this result to gas clouds in several astrophysical contexts, including galaxy clusters, galactic winds, the Galactic center, and the outskirts of the Galactic halo. Our results can explain the prevalence of cool gas in galactic winds and galactic halos and how such cool gas survives in spite of its interaction with hot wind/halo gas. We also predict that drag forces can lead t...

McCourt, Michael; Madigan, Ann-Marie; Quataert, Eliot

2014-01-01T23:59:59.000Z

445

X-ray Spectral Measurements of the Most Massive Stars: Stellar Wind Mass-Loss Rates and Shock Physics  

E-Print Network [OSTI]

X-ray Spectral Measurements of the Most Massive Stars: Stellar Wind Mass-Loss Rates and Shock/Themes: Significant technological advances in X-ray astronomy have driven discovery over the last few decades. New. The priorities at Swarthmore have allowed me to do careful work on the small number of X-ray spectral datasets

Cohen, David

446

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

447

Measuring Processing Speed Deficits in Multiple Sclerosis: A Comparison of Reaction Time and Rapid Serial Processing  

E-Print Network [OSTI]

2. Group diferences in the number of correct responses for related and unrelated words 33 3. Subinterval responses for groups on W, C, CW, and RI measures of the Stroop 37 4. Responses for patients and controls on each subinterval of the SDMT...; Arnet et al., 1997; Brasington & 8 Marsh, 1998; Zakzanis, 2000; DeLuca, Barbieri-Berger, & Johnson, 1994; Grigsby, Kaye, & Busenbark, 1994; Rao, et al., 1993; Coolidge, Middleton, Griego, & Schmidt, 1996;Beaty, Goodkin, Monson, Beaty, & Hersgard...

Hughes, Abbey Jean

2010-08-19T23:59:59.000Z

448

Large Area Divertor Temperature Measurements Using A High-speed Camera With Near-infrared FiIters in NSTX  

SciTech Connect (OSTI)

Fast cameras already installed on the National Spherical Torus Experiment (NSTX) have be equipped with near-infrared (NIR) filters in order to measure the surface temperature in the lower divertor region. Such a system provides a unique combination of high speed (> 50 kHz) and wide fi eld-of-view (> 50% of the divertor). Benchtop calibrations demonstrated the system's ability to measure thermal emission down to 330 oC. There is also, however, signi cant plasma light background in NSTX. Without improvements in background reduction, the current system is incapable of measuring signals below the background equivalent temperature (600 - 700 oC). Thermal signatures have been detected in cases of extreme divertor heating. It is observed that the divertor can reach temperatures around 800 oC when high harmonic fast wave (HHFW) heating is used. These temperature profiles were fi t using a simple heat diffusion code, providing a measurement of the heat flux to the divertor. Comparisons to other infrared thermography systems on NSTX are made.

Lyons, B C; Zweben, S J; Gray, T K; Hosea, J; Kaita, R; Kugel, H W; Maqueda, R J; McLean, A G; Roquemore, A L; Soukhanovskii, V A

2011-04-05T23:59:59.000Z

449

Measurements of air-sea gas exchange at high wind speeds in the Southern Ocean: Implications for global parameterizations  

E-Print Network [OSTI]

August 2006. [1] The SOLAS Air-Sea Gas Exchange (SAGE) Experiment was conducted in the western Pacific of air-sea gas exchange. Globally, the dominant control of air-sea gas exchange is turbulent energy as the primary source of energy for the atmospheric and oceanic molecular boundary layers have been derived from

Ho, David

450

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

451

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

452

Implementation and economical study of HAWT under different wind scenarios  

Science Journals Connector (OSTI)

Abstract Wind energy has seen a tremendous growth over the past decade and continues to grow into a major player into the renewable energy market. More than 3% of global electricity supply comes from wind power in 2012. The technology continues to mature thereby reducing the deployment cost at a value competing with the least expensive natural gas power plant. Diligent analysis of the wind including average wind speed, wind gust, boundary layer, seasonal and diurnal wind pattern adding to land mortgage, public perception, road and grid accessibility are all key factors for successful and profitable wind turbine implementation. In this work, the implementation of wind energy in Abu Dhabi was considered. In this study the annual wind data recorded every 10 min at Masdar metrological station over a period of three years from 2010 to 2012 are analyzed. The probability density distributions are derived from time series data and the distributional parameters are identified. It is followed by fitting the measured wind data with the maximum likelihood Weibull distribution. The power curves of two commercially available horizontal axis wind turbines (HAWTs) a large size 600 kW and small size 3.5 kW are coupled with the modelled data to account for the annual energy production and capacity factor. Considering the turbine efficiency, economical study that evaluates the cost of wind energy implementation, returns on investment are conducted accounting for capital cost, annuity, depreciation and operation and maintenance.

Franklyn Kanyako; Isam Janajreh

2014-01-01T23:59:59.000Z

453

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

454

Three-phase measurement evaluation using a high-speed processor with snapshot facility  

SciTech Connect (OSTI)

A homogeneous measurement evaluation system is presented which is able to provide all characteristic, electrical parameters in a HV substation. It can be applied to asymmetric and to distorted power systems. Its application software consists of four parts for each function: preprocessing, frequency shift, filtering, arithmetic functions. Its processor features the snapshot facility i.e. all voltage and current phases of one feeder can be picked up simultaneously thus eliminating interpolation errors. The accuracy of the evaluated parameters is C1.0.2 and C1.0.5 resp. including rms values of harmonics. Analog anti-aliasing filters are not required. Amplitude and phase errors of instrument transformers can be compensated. Since the applied processor is very fast, real-time results are obtained which meet even the stringent requirements of static Var compensators or other power electronics control equipment. An application for an EHV gas-insulated substation is described.

Brand, K.P.; Kopainsky, J.; Wittwer, F. (BBC Brown, Boveri and Cie., Ltd., CH-5401 Baden (CH))

1988-07-01T23:59:59.000Z

455

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

456

Effect of Blending on High-Pressure Laminar Flame Speed Measurements, Markstein Lengths, and Flame Stability of Hydrocarbons  

E-Print Network [OSTI]

, 5, and 10 .................................................. 40 Figure 26 Pure CH3OCH3 results for initial pressures of 1, 5, and 10 atm ................................................ 41 Figure 27 Flame speed results for 80/20 CH4/C2H6... .............................................................................................. 44 Figure 30 Flame speed results for 80/20 CH4/CH3OCH3 at initial pressures of 1, 5, and 10 atm compared to modeled results .................................................................................. 45 Figure 31 Flame speed results...

Lowry, William Baugh

2012-02-14T23:59:59.000Z

457

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

458

Narrowband sodium lidar for the measurements of mesopause region temperature and wind  

Science Journals Connector (OSTI)

We report here a narrowband high-spectral resolution sodium temperature/wind lidar recently developed at the University of Science and Technology of China (USTC) in Hefei, China...

Li, Tao; Fang, Xin; Liu, Wei; Gu, Sheng-Yang; Dou, Xiankang

2012-01-01T23:59:59.000Z

459

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

460

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

Note: This page contains sample records for the topic "measure wind speed" 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

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

462

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.

463

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

464

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

465

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

466

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

467

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

468

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

469

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

470

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

471

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:

472

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

473

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).

474

SAT-WIND project Final report  

E-Print Network [OSTI]

-2840 ISBN 87-550-3570-1 The SAT-WIND project `Winds from satellites for offshore and coastal wind energy) technologies for wind energy tools for wind resources and wind-indexing. The study area was the Danish Seas microwave polarimetric 223.3.1 History 3.3.2 Measurement principle 22 223.3.3 WindSat (passive microwave

475

Measurement and Numerical Simulation of Wind Environment for One Residential District  

E-Print Network [OSTI]

A residential quarter in the west of Changsha has a nearby main transport corridor to the east,and Tianma Hill is to the west. The circumference of this residential quarter is open to the outside; therefore, the wind environment is special...

Li, C.; Li, N.

2006-01-01T23:59:59.000Z

476

Measurement of the Equivalent Thermal Resistance of Rooftop Lawns in a Hot-Climate Wind Tunnel  

E-Print Network [OSTI]

rooftop lawn. A hot-climate wind tunnel experiment was carried out in order to obtain and analyze the heat and moisture transport in the rooftop lawn. Furthermore, a calculation with the energy conservation equation was carried out using the results...

Meng, Q.; Zhang, Y.; Zhang, L.

2006-01-01T23:59:59.000Z

477

Measurement of Wind-Induced Pressure Gradients in a Waste Rock Pile  

Science Journals Connector (OSTI)

...constraints can be determined. Funding for this research was...the wind blow through Yucca Mountain. p. 45-53. In D...High-Level Radioactive Waste Disposal. NUREG CP-0040. U...unsaturated zone waste disposal waste rock Western Canada...

Richard T. Amos; David W. Blowes; Leslie Smith; David C. Sego

478

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

479

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

480

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

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481

Evaluation of wind turbine noise levels and impact studies  

Science Journals Connector (OSTI)

Measured A?weighted sound levels at 125?ft distance for individual wind turbines with 20? to 120?kW power ratings are typically in the range 65–75 dB at moderate to high power output conditions (20–30?mph wind speeds). Tonelike sounds in the 300? to 1000?Hz frequency range often are clearly audible. Cyclical fluctuations of 10 dB in low?frequency noise levels are propagated by some downwind?type turbines. The random aerodynamic rotor noisesounds like a roar the gear box noisesounds like a whine and the low?frequency noise fluctuations sound like “thump?thump” or “whoosh?whoosh.” All of these wind turbinenoises are propagated from existing wind farms to residential areas and are judged intrusive and annoying. Measurements and predictions of wind turbinenoise submitted with applications for wind farm development have often contained errors which understated the noise levels by 3–10 dB. These errors were due to noisemeasurements at minimal wind speeds and turbine power and faulty modeling procedures. Simple analytical expressions have been developed which quickly and accurately predict the noise levels for large turbine arrays.

Samuel R. Lane

1986-01-01T23:59:59.000Z

482

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

483

The wind potential impact on the maximum wind energy penetration in autonomous electrical grids  

Science Journals Connector (OSTI)

According to long-term wind speed measurements the Aegean Archipelago possesses excellent wind potential, hence properly designed wind energy applications can substantially contribute to fulfill the energy requirements of the island societies. On top of this, in most islands the electricity production cost is extremely high, while significant insufficient power supply problems are often encountered, especially during the summer. Unfortunately, the stochastic behaviour of the wind and the important fluctuations of daily and seasonal electricity load pose a strict penetration limit for the contribution of wind energy in the corresponding load demand. The application of this limit is necessary in order to avoid hazardous electricity grid fluctuations and to protect the existing thermal power units from operating near or below their technical minima. In this context, the main target of the proposed study is to present an integrated methodology able to estimate the maximum wind energy penetration in autonomous electrical grids on the basis of the available wind potential existing in the Aegean Archipelago area. For this purpose a large number of representative wind potential types have been investigated and interesting conclusions have been derived.

J.K. Kaldellis

2008-01-01T23:59:59.000Z

484

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

485

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

486

Characterizing Inflow Conditions Across the Rotor Disk of a Utility-Scale Wind Turbine (Poster)  

SciTech Connect (OSTI)

Multi-megawatt utility-scale wind turbines operate in a turbulent, thermally-driven atmosphere where wind speed and air temperature vary with height. Turbines convert the wind's momentum into electrical power, and so changes in the atmosphere across the rotor disk influence the power produced by the turbine. To characterize the inflow into utility scale turbines at the National Wind Technology Center (NWTC) near Boulder, Colorado, NREL recently built two 135-meter inflow monitoring towers. This poster introduces the towers and the measurements that are made, showing some of the data obtained in the first few months of operation in 2011.

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

2012-01-01T23:59:59.000Z

487

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

488

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

489

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

490

Measurable energy savings of installing variable frequency drives for cooling towers’ fans, compared to dual speed motors  

Science Journals Connector (OSTI)

Abstract In recent years the building management system (BMS) controllers have been used to control the operation of heating, ventilation, and air conditioning system in addition to lighting and some electrical equipment in order to save energy. In the water cooled system, the BMS controls the operation process of the cooling towers (CTs) fans of dual speed motors to maintain a constant leaving water temperature for different cooling loads and different ambient wet bulb temperature (WBT). This paper presents the effect of installing variable frequency drives (VFDs) for \\{CTs\\} fans in Kuwait during summer season on energy savings compared to dual speed control. The results have shown that with VFD mode, the reduction in water consumption was over 13% compared to the commonly used dual speed mode. More importantly, the combined power for the chillers and the \\{CTs\\} fans for the same amount of cooling produced were reduced by 5.8% in the VFD mode.

E. Al-Bassam; R. Alasseri

2013-01-01T23:59:59.000Z

491

Verification of Supercooled Cloud Water Forecasts with In Situ Aircraft Measurements  

Science Journals Connector (OSTI)

In situ measurements of temperature (Ta), horizontal wind speed (V), dewpoint (Td), total water content (TWC), and cloud and supercooled cloud water (SCW) events, made during 50 flights from three research field programs, have been compared to ...

Hong Guan; Stewart G. Cober; George A. Isaac

2001-02-01T23:59:59.000Z

492

CALIBRATION OF AND ATTITUDE ERROR ESTIMATION FOR A SPACEBORNE SCATTEROMETER USING MEASUREMENTS OVER LAND  

E-Print Network [OSTI]

of ocean wind speed and direction. Scatterometers must be calibrated before their measurements are scienti in the long-term, thus propelling them out of the crowded valley of the common and up the inclines

Long, David G.