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Note: This page contains sample records for the topic "turbulence wind variability" 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

Supercomputers Capture Turbulence in the Solar Wind  

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

Capture Turbulence in the Solar Wind Supercomputers Capture Turbulence in the Solar Wind Berkeley Lab visualizations could help scientists forecast destructive space weather...

2

Supercomputers Capture Turbulence in the Solar Wind  

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

Supercomputers Supercomputers Capture Turbulence in the Solar Wind Supercomputers Capture Turbulence in the Solar Wind Berkeley Lab visualizations could help scientists forecast destructive space weather December 16, 2013 Linda Vu, +1 510 495 2402, lvu@lbl.gov eddies1.jpg This visualization zooms in on current sheets revealing the "cascade of turbulence" in the solar wind occurring down to electron scales. This is a phenomenon common in fluid dynamics-turbulent energy injected at large eddies is transported to successively smaller scales until it is dissipated as heat. (Image by Burlen Loring, Berkeley Lab) As inhabitants of Earth, our lives are dominated by weather. Not just in the form of rain and snow from atmospheric clouds, but also a sea of charged particles and magnetic fields generated by a star sitting 93

3

Surface Wind Direction Variability  

Science Journals Connector (OSTI)

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

Larry Mahrt

2011-01-01T23:59:59.000Z

4

Supercomputers Capture Turbulence in the Solar Wind  

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

Supercomputers Capture Supercomputers Capture Turbulence in the Solar Wind News & Publications ESnet in the News ESnet News Media & Press Publications and Presentations Galleries ESnet Awards and Honors Contact Us Technical Assistance: 1 800-33-ESnet (Inside the US) 1 800-333-7638 (Inside the US) 1 510-486-7600 (Globally) 1 510-486-7607 (Globally) Report Network Problems: trouble@es.net Provide Web Site Feedback: info@es.net Supercomputers Capture Turbulence in the Solar Wind Berkeley Lab visualizations could help scientists forecast destructive space weather December 16, 2013 | Tags: ESnet News, National Energy Research Scientific Computing Linda Vu, +1 510 495 2402, lvu@lbl.gov eddies1.jpg This visualization zooms in on current sheets revealing the "cascade of turbulence" in the solar wind occurring down to electron scales. This is

5

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

6

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

7

Buoyancy-generated variable-density turbulence  

SciTech Connect (OSTI)

Because of the importance of turbulence mixing in many applications, a number of turbulence mixing models have been proposed for variable- density flows. These engineering models (one- point statistical models) typically include the transport of the turbulent kinetic energy and the turbulent energy dissipation rate (i.e., k - {epsilon} models). The model presented by Besnard, Harlow, Rauenzahn and Zemach (1992) (herein referred to as BHRZ) is a one-point model intended to describe variable-density turbulent flows. Transport equations for the Reynolds stress tensor, R{sub ij}, and the turbulent energy dissipation rate, the density-velocity correlation, a{sub i}, and the density-specific volume correlation, b are derived. This model employs- techniques and concepts from incompressible, constant- density turbulence modeling and incorporates ideas from two-phase flow models. Clark and Spitz (1994) present a two-point model for variable-density turbulence. Their derivation is based on transport equations that, are based 0481 on two-point- generalizations of R{sub ij}, a{sub ij}, and b. These equations are Fourier transformed with respect to the separation distance between the two points. Transport equations are derived for R{sub ij}, a{sub i}, b. As in the one-point model, this model contains many ad-hoc assumptions and unknown model coefficients that must be determined by comparison with experimental and numerical data. However, the two-point formalism requires fewer equilibrium assumptions then does a single-point model. Our primary concern in this paper lies in the nonlinear processes of turbulence and the influence of large density variations (not within the Boussinesq limit) on these processes. To. isolate the effects of variable-density on the turbulence we restrict our flow to be incompressible, statistically homogeneous buoyancy-generated. turbulence. To our knowledge there have not been any simulations reported for this problem.

Sandoval, D.L.; Clark, T.T.; Riley, J.J.

1996-07-01T23:59:59.000Z

8

Buoyancy-generated variable-density turbulence  

SciTech Connect (OSTI)

Both a one-point (engineering) and a two-point (spectral) model are tested against numerical data. Deficiencies in these variable-density models are disucssed and modifications are suggested. Attention is restricted to turbulent interactions of two miscible, incompressible Newtonian fluids of different densities. Departures from the limits of validity of the Boussinesq approximation are examined. Results of the buoyancy-generated turbulence are compared with variable-density model predictions. 3 figs, 6 refs.

Sandoval, D.L. [Los Alamos National Lab., NM (United States)]|[Washington Univ. (United States); Clark, T.T. [Los Alamos National Lab., NM (United States); Riley, J.J. [Washington Univ. (United States)

1996-06-01T23:59:59.000Z

9

The dynamics of variable-density turbulence  

SciTech Connect (OSTI)

The dynamics of variable-density turbulent fluids are studied by direct numerical simulation. The flow is incompressible so that acoustic waves are decoupled from the problem, and implying that density is not a thermodynamic variable. Changes in density occur due to molecular mixing. The velocity field, is in general, divergent. A pseudo-spectral numerical technique is used to solve the equations of motion. Three-dimensional simulations are performed using a grid size of 128{sup 3} grid points. Two types of problems are studied: (1) the decay of isotropic, variable-density turbulence, and (2) buoyancy-generated turbulence in a fluid with large density fluctuations. In the case of isotropic, variable-density turbulence, the overall statistical decay behavior, for the cases studied, is relatively unaffected by the presence of density variations when the initial density and velocity fields are statistically independent. The results for this case are in quantitative agreement with previous numerical and laboratory results. In this case, the initial density field has a bimodal probability density function (pdf) which evolves in time towards a Gaussian distribution. The pdf of the density field is symmetric about its mean value throughout its evolution. If the initial velocity and density fields are statistically dependent, however, the decay process is significantly affected by the density fluctuations. For the case of buoyancy-generated turbulence, variable-density departures from the Boussinesq approximation are studied. The results of the buoyancy-generated turbulence are compared with variable-density model predictions. Both a one-point (engineering) model and a two-point (spectral) model are tested against the numerical data. Some deficiencies in these variable-density models are discussed and modifications are suggested.

Sandoval, D.L.

1995-11-01T23:59:59.000Z

10

Nature of Subproton Scale Turbulence in the Solar Wind  

Science Journals Connector (OSTI)

The nature of subproton scale fluctuations in the solar wind is an open question, partly because two similar types of electromagnetic turbulence can occur: kinetic Alfvén turbulence and whistler turbulence. These two possibilities, however, have one key qualitative difference: whistler turbulence, unlike kinetic Alfvén turbulence, has negligible power in density fluctuations. In this Letter, we present new observational data, as well as analytical and numerical results, to investigate this difference. These results show, for the first time, that the fluctuations well below the proton scale are predominantly kinetic Alfvén turbulence, and, if present at all, the whistler fluctuations make up only a small fraction of the total energy.

C. H. K. Chen; S. Boldyrev; Q. Xia; J. C. Perez

2013-05-31T23:59:59.000Z

11

Coupled multi-body dynamics and CFD for wind turbine simulation including explicit wind turbulence  

Science Journals Connector (OSTI)

Abstract A high fidelity approach for wind turbine aero-elastic simulations including explicit representation of the atmospheric wind turbulence is presented. The approach uses a dynamic overset computational fluid dynamics (CFD) code for the aerodynamics coupled with a multi-body dynamics (MBD) code for the motion responses to the aerodynamic loads. Mann's wind turbulence model was implemented into the CFD code as boundary and initial conditions. The wind turbulence model was validated by comparing the theoretical one-point spectrum for the three components of the velocity fluctuations, and by comparing the expected statistics from the CFD simulated wind turbulent field with the explicit wind turbulence inlet boundary from Mann model. Extensive simulations based on the proposed coupled approach were conducted with the conceptual NREL 5-MW offshore wind turbine in an increasing level of complexity, analyzing the turbine behavior as elasticity, wind shear and atmospheric wind turbulence are added to the simulations. Results are compared with the publicly available simulations results from OC3 participants, showing good agreement for the aerodynamic loads and blade tip deflections in time and frequency domains. Wind turbulence/turbine interaction was examined for the wake flow. It was found that explicit turbulence addition results in considerably increased wake diffusion. The coupled CFD/MBD approach can be extended to include multibody models of the shaft, bearings, gearbox and generator, resulting in a promising tool for wind turbine design under complex operational environments.

Y. Li; A.M. Castro; T. Sinokrot; W. Prescott; P.M. Carrica

2015-01-01T23:59:59.000Z

12

Wind Energy Applications of Unified and Dynamic Turbulence Models  

E-Print Network [OSTI]

Wind Energy Applications of Unified and Dynamic Turbulence Models Stefan Heinz and Harish Gopalan applicable as a low cost alternative. 1 Introduction There is a growing interest in using wind energy suggests the possibility of providing 20% of the electricity in the U.S. by wind energy in 2030

Heinz, Stefan

13

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

14

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

15

The dynamics of variable-density turbulence  

SciTech Connect (OSTI)

The dynamics of variable-density turbulent fluids are studied by direct numerical simulation. The flow is incompressible so that acoustic waves are decoupled from the problem, and implying that density is not a thermodynamic variable. Changes in density occur due to molecular mixing. The velocity field is, in general, divergent. A pseudo-spectral numerical technique is used to solve the equations of motion. Three-dimensional simulations are performed using a grid size of 128{sup 3} grid points. Two types of problems are studied: (1) the decay of isotropic, variable-density turbulence, and (2) buoyancy-generated turbulence in a fluid with large density fluctuations (such that the Boussinesq approximation is not valid). In the case of isotropic, variable-density turbulence, the overall statistical decay behavior, for the cases studied, is relatively unaffected by the presence of density variations when the initial density and velocity fields are statistically independent. The results for this case are in quantitative agreement with previous numerical and laboratory results. In this case, the initial density field has a bimodal probability density function (pdf) which evolves in time towards a Gaussian distribution. The pdf of the density field is symmetric about its mean value throughout its evolution. If the initial velocity and density fields are statistically dependent, however, the decay process is significantly affected by the density fluctuations. For this case, the pdf of the density becomes asymmetric about its mean value during the early stages of its evolution. It is argued that these asymmetries in the pdf of the density field are due to different entrainment rates, into the mixing region, that favor the high speed fluid.

Sandoval, D.L.

1995-11-01T23:59:59.000Z

16

COLLISIONLESS DAMPING AT ELECTRON SCALES IN SOLAR WIND TURBULENCE  

SciTech Connect (OSTI)

The dissipation of turbulence in the weakly collisional solar wind plasma is governed by unknown kinetic mechanisms. Two candidates have been suggested to play an important role in the dissipation, collisionless damping via wave-particle interactions and dissipation in small-scale current sheets. High resolution spacecraft measurements of the turbulent magnetic energy spectrum provide important constraints on the dissipation mechanism. The limitations of popular fluid and hybrid numerical schemes for simulation of the dissipation of solar wind turbulence are discussed, and instead a three-dimensional kinetic approach is recommended. We present a three-dimensional nonlinear gyrokinetic simulation of solar wind turbulence at electron scales that quantitatively reproduces the exponential form of the turbulent magnetic energy spectrum measured in the solar wind. A weakened cascade model that accounts for nonlocal interactions and collisionless Landau damping also quantitatively agrees with the observed exponential form. These results establish that a turbulent cascade of kinetic Alfven waves that is terminated by collisionless Landau damping is sufficient to explain the observed magnetic energy spectrum in the dissipation range of solar wind turbulence.

TenBarge, J. M.; Howes, G. G. [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); Dorland, W., E-mail: jason-tenbarge@uiowa.edu [Department of Physics, University of Maryland, College Park, MA 20742-3511 (United States)

2013-09-10T23:59:59.000Z

17

A Dynamical Model of Plasma Turbulence in the Solar Wind  

E-Print Network [OSTI]

A dynamical approach, rather than the usual statistical approach, is taken to explore the physical mechanisms underlying the nonlinear transfer of energy, the damping of the turbulent fluctuations, and the development of coherent structures in kinetic plasma turbulence. It is argued that the linear and nonlinear dynamics of Alfven waves are responsible, at a very fundamental level, for some of the key qualitative features of plasma turbulence that distinguish it from hydrodynamic turbulence, including the anisotropic cascade of energy and the development of current sheets at small scales. The first dynamical model of kinetic turbulence in the weakly collisional solar wind plasma that combines self-consistently the physics of Alfven waves with the development of small-scale current sheets is presented and its physical implications are discussed. This model leads to a simplified perspective on the nature of turbulence in a weakly collisional plasma: the nonlinear interactions responsible for the turbulent casca...

Howes, G G

2015-01-01T23:59:59.000Z

18

Turbulence Characteristics in Offshore Wind Farms from LES Simulations of Lillgrund Wind Farm  

Science Journals Connector (OSTI)

Abstract The effect of wind turbine wakes in large offshore wind energy arrays can be a substantial factor in affecting the performance of turbines inside the array. Turbulent mixing plays a key role in the wake recovery, having a significant effect on the length over which the wake is strong enough to affect the performance of other turbines significantly. We highlight how turbulence affects wind turbine wakes using results from LES simulations of Lillgrund offshore wind farm in the context of SCADA data selected to mirror the wind conditions simulated. The analysis here concentrated on temporal spectra of wind velocities measured by the turbine's nacelle anemometer and calculated at the turbine locations in the computational model. The effect of the wind turbine rotor on the downstream flow is quantified by analysing the change in spectral features of turbines within the wind farm compared to turbines at the side of the farm exposed to the wind.

Wolf-Gerrit Früh; Angus C.W. Creech; A. Eoghan Maguire

2014-01-01T23:59:59.000Z

19

Wind noise and the spectrum of atmospheric turbulence pressure fluctuations  

Science Journals Connector (OSTI)

Previous research [S. Morgan and R. Raspet J. Acoust. Soc. Am. 92 1180–1183 (1992)] has shown that wind noise is predominantly caused by pressure fluctuations intrinsic to the turbulent atmospheric flow. Therefore it should be possible to predict wind noise from models for turbulent pressure spectra in the atmosphere. Based on simple dimensional analysis and an application of Taylor’s hypothesis the inertial?subrange power spectrum for turbulent pressure fluctuations should be proportional to f ?7/3 where f is frequency. But more recent atmospheric observations and theoretical arguments [J. D. Albertson G. G. Katul M. B. Parlange and W. E. Eichinger Phys. Fluids 10 1725–1732 (1998)] suggest that the power spectrum actually goes as f ?3/2. In this paper it is shown that the f ?3/2 dependence predicts a much slower decay in wind noise with increasing acoustic frequency than is typically observed. Possible reasons for this discrepancy are discussed.

2003-01-01T23:59:59.000Z

20

A Tree Swaying in a Turbulent Wind: A Scaling Analysis  

E-Print Network [OSTI]

A tentative scaling theory is presented of a tree swaying in a turbulent wind. It is argued that the turbulence of the air within the crown is in the inertial regime. An eddy causes a dynamic bending response of the branches according to a time criterion. The resulting expression for the penetration depth of the wind yields an exponent which appears to be consistent with that pertaining to the morphology of the tree branches. An energy criterion shows that the dynamics of the branches is basically passive. The possibility of hydrodynamic screening by the leaves is discussed.

Theo Odijk

2014-07-10T23:59:59.000Z

Note: This page contains sample records for the topic "turbulence wind variability" 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

Turbulent heating of the corona and solar wind: the heliospheric  

E-Print Network [OSTI]

resembles magnetic lines of force Eclipse observations show the `solar corona' Thomson-scattered white light ­ photospheric light scattered from dust, solar spectrum remains ­ `zodiacal light' E corona ­ emission linesTurbulent heating of the corona and solar wind: the heliospheric dark energy problem Stuart D. Bale

22

Residual energy in magnetohydrodynamic turbulence and in the solar wind  

E-Print Network [OSTI]

Recent observations indicate that kinetic and magnetic energies are not in equipartition in the solar wind turbulence. Rather, magnetic fluctuations are more energetic and have somewhat steeper energy spectrum compared to the velocity fluctuations. This leads to the presence of the so-called residual energy E_r=E_v-E_b in the inertial interval of turbulence. This puzzling effect is addressed in the present paper in the framework of weak turbulence theory. Using a simple model of weakly colliding Alfv\\'en waves, we demonstrate that the kinetic-magnetic equipartition indeed gets broken as a result of nonlinear interaction of Alfv\\'en waves. We establish that magnetic energy is indeed generated more efficiently as a result of these interactions, which proposes an explanation for the solar wind observations.

Stanislav Boldyrev; Jean Carlos Perez; Vladimir Zhdankin

2011-08-30T23:59:59.000Z

23

Reconnection outflow generated turbulence in the solar wind  

E-Print Network [OSTI]

Petschek-type time-dependent reconnection (TDR) and quasi-stationary reconnection (QSR) models are considered to understand reconnection outflow structures and the features of the associated locally generated turbulence in the solar wind. We show that the outflow structures, such as discontinuites, Kelvin-Helmholtz (KH) unstable flux tubes or continuous space filling flows cannot be distinguished from one-point WIND measurements. In both models the reconnection outflows can generate more or less spatially extended turbulent boundary layers (TBDs). The structure of an unique extended reconnection outflow is investigated in detail. The analysis of spectral scalings and break locations show that reconnection outflows can control the local field and plasma conditions which may play in favor of one or another turbulent dissipation mechanisms with their characteristic scales and wavenumbers.

Vörös, Z; Semenov, V S; Zaqarashvili, T V; Bruno, R; Khodachenko, M

2014-01-01T23:59:59.000Z

24

Atmospheric and Wake Turbulence Impacts on Wind Turbine Fatigue Loadings  

SciTech Connect (OSTI)

Large-eddy simulations of atmospheric boundary layers under various stability and surface roughness conditions are performed to investigate the turbulence impact on wind turbines. In particular, the aeroelastic responses of the turbines are studied to characterize the fatigue loading of the turbulence present in the boundary layer and in the wake of the turbines. Two utility-scale 5-MW turbines that are separated by seven rotor diameters are placed in a 3 km by 3 km by 1 km domain. They are subjected to atmospheric turbulent boundary layer flow and data is collected on the structural response of the turbine components. The surface roughness was found to increase the fatigue loads while the atmospheric instability had a small influence. Furthermore, the downstream turbines yielded higher fatigue loads indicating that the turbulent wakes generated from the upstream turbines have significant impact.

Lee, S.; Churchfield, M.; Moriarty, P.; Jonkman, J.; Michalakes, J.

2012-01-01T23:59:59.000Z

25

Two-Dimensional Kinetic Turbulence in the Solar Wind  

Science Journals Connector (OSTI)

We present the first 2D hybrid-Vlasov simulations of turbulence in the solar wind that describe the evolution of the energy spectra in a range of two decades of wavelengths around the ion inertial scale. Several previous magnetohydrodynamics and particle-in-cell simulations in the range of large (fluid) wavelengths showed a marked anisotropy of the energy spectra in the direction perpendicular to the mean magnetic field. Here we give evidence that the parallel direction can also be a privileged way for turbulence to develop towards short scales, where kinetic effects govern the plasma dynamics.

F. Valentini; F. Califano; P. Veltri

2010-05-17T23:59:59.000Z

26

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

27

Large-eddy simulation of a wind turbine wake in turbulent  

E-Print Network [OSTI]

Large-eddy simulation of a wind turbine wake in turbulent neutral shear flow Shengbai Xie, Cristina-similar velocity profile existing in the wake after a wind turbine? How does the wake influence the vertical? Motivation #12; Large-eddy simulation for turbulent flow field Actuator-line model for wind turbine ui

Firestone, Jeremy

28

On the use of proper orthogonal decomposition to describe inflow turbulence and wind turbine loads  

E-Print Network [OSTI]

of POD modes needed to accurately describe wind turbine blade and tower loads depends primarilyOn the use of proper orthogonal decomposition to describe inflow turbulence and wind turbine loads, USA Keywords: Proper Orthogonal Decomposition, inflow turbulence, wind turbine ABSTRACT: We discuss

Manuel, Lance

29

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

30

The translation of turbulent wind energy to individual corn plant motion during senescense  

Science Journals Connector (OSTI)

Wind flow within inflexible plant canopies is turbulent and leads to an oscillatory motion of individual plants. A study was conducted to describe the motion of corn (Zea mays...L.) stalks in the wind using a tra...

T. K. Flesch; R. H. Grant

1991-04-01T23:59:59.000Z

31

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

32

Modeling variable density effects in turbulent flames -- Some basic considerations  

SciTech Connect (OSTI)

The paper discusses the basic physical phenomena involved in pressure-density interactions, and presents models of pressure-velocity, pressure-scalar, baroclinic and dilatation effects for variable density low Mach-number turbulence. Their implementation in the {kappa}-{epsilon} framework is then described and their performance evaluated. The models assume that both scalar transport and turbulence generation arising from pressure-density interactions in flames are caused by the motion of large scale turbulent thermals superposed on the normal turbulence mechanism. The velocity of the thermals is related directly to the mean pressure gradient and local density differences in the flames. It is furthermore assumed that the correction for dilatation effects in the {kappa}-{epsilon} system can be determined from the constraint of conservation of the angular momentum of turbulence per unit mass. Simple corrections of the {kappa}-{epsilon} system are proposed for fast chemistry diffusion and premixed flames subject to variable pressure gradients, which offer substantial improvements in the predictions of the flames. some problems remain, particularly in predictions of turbulence in premixed flames, owing to large scale instabilities of the flames observed in the experiments.

Chomiak, J.; Nisbet, J.R. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Thermo and Fluid Dynamics] [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Thermo and Fluid Dynamics

1995-08-01T23:59:59.000Z

33

Variables Affecting Economic Development of Wind Energy  

SciTech Connect (OSTI)

NREL's JEDI Wind model performed an analysis of wind-power-related economic development drivers. Economic development benefits for wind and coal were estimated using NREL's JEDI Wind and JEDI Coal models.

Lantz, E.; Tegen, S.

2008-07-01T23:59:59.000Z

34

Variables Affecting Economic Development of Wind Energy  

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

Variables Affecting Economic Variables Affecting Economic Development of Wind Energy E. Lantz and S. Tegen National Renewable Energy Laboratory Presented at WINDPOWER 2008 Houston, Texas June 1-4, 2008 Conference Paper NREL/CP-500-43506 July 2008 NREL is operated by Midwest Research Institute ● Battelle 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. This report was prepared as an account of work sponsored by an agency of the United States government.

35

Scaling of the electron dissipation range of solar wind turbulence  

E-Print Network [OSTI]

Electron scale solar wind turbulence has attracted great interest in recent years. Clear evidences have been given from the Cluster data that turbulence is not fully dissipated near the proton scale but continues cascading down to the electron scales. However, the scaling of the energy spectra as well as the nature of the plasma modes involved at those small scales are still not fully determined. Here we survey 10 years of the Cluster search-coil magnetometer (SCM) waveforms measured in the solar wind and perform a statistical study of the magnetic energy spectra in the frequency range [$1, 180$]Hz. We show that a large fraction of the spectra exhibit clear breakpoints near the electon gyroscale $\\rho_e$, followed by steeper power-law like spectra. We show that the scaling below the electron breakpoint cannot be determined unambiguously due to instrumental limitations that will be discussed in detail. We compare our results to recent ones reported in other studies and discuss their implication on the physical...

Sahraoui, F; De Patoul, J; Belmont, G; Goldstein, M L; Retino, A; Robert, P; Cornilleau-Wehrlin, N; Canu, P

2013-01-01T23:59:59.000Z

36

Optimal combined wind power forecasts using exogeneous variables  

E-Print Network [OSTI]

Optimal combined wind power forecasts using exogeneous variables Fannar ¨Orn Thordarson Kongens of the thesis is combined wind power forecasts using informations from meteorological forecasts. Lyngby, January

37

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

38

Simulating Turbulent Wind Fields for Offshore Turbines in Hurricane-Prone Regions (Poster)  

SciTech Connect (OSTI)

Extreme wind load cases are one of the most important external conditions in the design of offshore wind turbines in hurricane prone regions. Furthermore, in these areas, the increase in load with storm return-period is higher than in extra-tropical regions. However, current standards have limited information on the appropriate models to simulate wind loads from hurricanes. This study investigates turbulent wind models for load analysis of offshore wind turbines subjected to hurricane conditions. Suggested extreme wind models in IEC 61400-3 and API/ABS (a widely-used standard in oil and gas industry) are investigated. The present study further examines the wind turbine response subjected to Hurricane wind loads. Three-dimensional wind simulator, TurbSim, is modified to include the API wind model. Wind fields simulated using IEC and API wind models are used for an offshore wind turbine model established in FAST to calculate turbine loads and response.

Guo, Y.; Damiani, R.; Musial, W.

2014-04-01T23:59:59.000Z

39

A Comparison of Wind Turbine Load Statistics for Inflow Turbulence Fields based on Conventional  

E-Print Network [OSTI]

A Comparison of Wind Turbine Load Statistics for Inflow Turbulence Fields based on Conventional for a utility-scale 5MW wind turbine. Load statistics, spectra, and time-frequency analysis representations utility-scale wind turbines. The present study takes on this question by making use of conventional

Manuel, Lance

40

Offshore Series Wind Turbine Variable Hub heights & rotor diameters  

E-Print Network [OSTI]

3.6MW Offshore Series Wind Turbine GE Energy #12;Feature Variable Hub heights & rotor diameters-savings feature, considering the rigors of offshore power generation. The 3.6 MW offshore wind turbine also, for both on and offshore use. Special features include... As the world's first commercially available wind

Firestone, Jeremy

Note: This page contains sample records for the topic "turbulence wind variability" 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

Large-Eddy Simulation of Langmuir Turbulence in Pure Wind Seas  

Science Journals Connector (OSTI)

The scaling of turbulent kinetic energy (TKE) and its vertical component (VKE) in the upper ocean boundary layer, forced by realistic wind stress and surface waves including the effects of Langmuir circulations, is investigated using large-eddy ...

Ramsey R. Harcourt; Eric A. D’Asaro

2008-07-01T23:59:59.000Z

42

Simulation of Turbulent Flow Inside and Above Wind Farms: Model Validation and Layout Effects  

Science Journals Connector (OSTI)

A recently-developed large-eddy simulation framework is validated and used to investigate turbulent flow within and above wind farms under neutral conditions. Two different layouts are considered, consisting of t...

Yu-Ting Wu; Fernando Porté-Agel

2013-02-01T23:59:59.000Z

43

Large Eddy Simulation of Wind Turbulence for Appropriate Urban Environment  

Science Journals Connector (OSTI)

This study shows the numerical model which has the actual shape of the urban surface in order to analyze the wind turbulence in a city by large eddy simulation (LES) technique. Predictive accuracy of LES ... haza...

Tetsuro Tamura

2010-01-01T23:59:59.000Z

44

Electron and proton heating by solar wind turbulence B. Breech,1  

E-Print Network [OSTI]

Electron and proton heating by solar wind turbulence B. Breech,1 W. H. Matthaeus,2 S. R. Cranmer,3; published 16 September 2009. [1] Previous formulations of heating and transport associated with strong and protons. Electron heat conduction is included. Energy is supplied by turbulent heating that affects both

Oughton, Sean

45

Prediction of the Proton-to-Total Turbulent Heating in the Solar Wind  

E-Print Network [OSTI]

This paper employs a recent turbulent heating prescription to predict the ratio of proton-to-total heating due to the kinetic dissipation of Alfvenic turbulence as a function of heliocentric distance. Comparing to a recent empirical estimate for this turbulent heating ratio in the high-speed solar wind, the prediction shows good agreement with the empirical estimate for R >~ 0.8 AU, but predicts less ion heating than the empirical estimate at smaller heliocentric radii. At these smaller radii, the turbulent heating prescription, calculated in the gyrokinetic limit, fails because the turbulent cascade is predicted to reach the proton cyclotron frequency before Landau damping terminates the cascade. These findings suggest that the turbulent cascade can reach the proton cyclotron frequency at R ~ 0.8 AU, this turbulent heating prescription contains all of the necessary physical mechanisms needed to reproduce the empirically estimated proton-to-total heating ratio.

Howes, G G

2011-01-01T23:59:59.000Z

46

Experimental evidence of phase coherence of magnetohydrodynamic turbulence in the solar wind: GEOTAIL satellite data  

Science Journals Connector (OSTI)

...research, the amplitude (power spectrum) has been discussed...Saito 1969) and the power-law type spectrum of...turbulence in the solar wind (Goldstein Roberts 1999...spacecraft in the solar wind. From the original data...original data into the power spectrum and the phases...

2008-01-01T23:59:59.000Z

47

Turbulence-induced resonance vibrations cause pollen release in wind-pollinated Plantago lanceolata L. (Plantaginaceae)  

Science Journals Connector (OSTI)

...can, potentially, transfer mechanical energy to the stamens because of the predominant...spectrum of the wind turbulent kinetic energy. Also included are PSDs of (c) the displacement...28 Flesch, TK , and RH Grant. 1992 Corn motion in the wind during senescence...

2014-01-01T23:59:59.000Z

48

Propagation of Wind Energy into the Deep Ocean through a Fully Turbulent Mesoscale Eddy Field  

Science Journals Connector (OSTI)

The authors analyze the 3D propagation of wind-forced near-inertial motions in a fully turbulent mesoscale eddy field with a primitive equation numerical model. Although the wind stress is uniform, the near-inertial motion field quickly becomes ...

Eric Danioux; Patrice Klein; Pascal Rivière

2008-10-01T23:59:59.000Z

49

Intra-hour wind power variability assessment using the conditional range metric : quantification, forecasting and applications.  

E-Print Network [OSTI]

??The research presented herein concentrates on the quantification, assessment and forecasting of intra-hour wind power variability. Wind power is intrinsically variable and, due to the… (more)

Boutsika, Thekla

2013-01-01T23:59:59.000Z

50

Permutation Entropy and Statistical Complexity Analysis of Turbulence in Laboratory Plasmas and the Solar Wind  

E-Print Network [OSTI]

The Bandt-Pompe permutation entropy and the Jensen-Shannon statistical complexity are used to analyze fluctuating time series of three different plasmas: the magnetohydrodynamic (MHD) turbulence in the plasma wind tunnel of the Swarthmore Spheromak Experiment (SSX), drift-wave turbulence of ion saturation current fluctuations in the edge of the Large Plasma Device (LAPD) and fully-developed turbulent magnetic fluctuations of the solar wind taken from the WIND spacecraft. The entropy and complexity values are presented as coordinates on the CH plane for comparison among the different plasma environments and other fluctuation models. The solar wind is found to have the highest permutation entropy and lowest statistical complexity of the three data sets analyzed. Both laboratory data sets have larger values of statistical complexity, suggesting these systems have fewer degrees of freedom in their fluctuations, with SSX magnetic fluctuations having slightly less complexity than the LAPD edge fluctuations. The CH ...

Weck, Peter J; Brown, Michael R; Wicks, Robert T

2014-01-01T23:59:59.000Z

51

The Wind of Variable C in M33  

E-Print Network [OSTI]

We discuss the spectrum of Var C in M33 obtained just before the onset of its current brightening and recent spectra during its present "eruption" or optically thick wind stage. These spectra illustrate the typical LBV transition in apparent spectral type or temperature that characterizes the classical LBV or S Dor-type variability. LBVs are known to have slow, dense winds during their maximum phase. Interestingly, Var C had a slow wind even during its hot, quiescent stage in comparison with the normal hot supergiants with similar temperatures. Its outflow or wind speeds also show very little change between these two states.

Humphreys, Roberta M; Gordon, Michael; Weis, Kerstin; Burggraf, Birgitta; Bomans, D J; Martin, John C

2014-01-01T23:59:59.000Z

52

Petascale Simulations of Inhomogeneous Alfven Turbulence in the Solar Wind  

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

A snapshot of turbulent magnetic field lines (red) inside a coronal hole that expands from a small patch on the solar surface to 5 solar radii A snapshot of turbulent magnetic field lines (red) inside a coronal hole that expands from a small patch on the solar surface to 5 solar radii A snapshot of turbulent magnetic field lines (red) inside a coronal hole that expands from a small patch on the solar surface to 5 solar radii. Alfven waves (AW), launched by convective motions on the photosphere, propagate in the inhomogeneous Solar atmosphere producing primary reflected waves that interact non-linearly with the outward waves, driving a turbulent cascade. This cascade continues with secondary reflections in a very complex interplay between wave reflections and nonlinear interactions. Selected slices across the simulation domain show contours of plasma current, indicating the generation of small scale structures where the

53

PREDICTION OF THE PROTON-TO-TOTAL TURBULENT HEATING IN THE SOLAR WIND  

SciTech Connect (OSTI)

This paper employs a recent turbulent heating prescription to predict the ratio of proton-to-total heating due to the kinetic dissipation of Alfvenic turbulence as a function of heliocentric distance. Comparing to a recent empirical estimate for this turbulent heating ratio in the high-speed solar wind, the prediction shows good agreement with the empirical estimate for R {approx}> 0.8 AU, but predicts less ion heating than the empirical estimate at smaller heliocentric radii. At these smaller radii, the turbulent heating prescription, calculated in the gyrokinetic limit, fails because the turbulent cascade is predicted to reach the proton cyclotron frequency before Landau damping terminates the cascade. These findings suggest that the turbulent cascade can reach the proton cyclotron frequency at R {approx}< 0.8 AU, leading to a higher level of proton heating than predicted by the turbulent heating prescription in the gyrokinetic limit. At larger heliocentric radii, R {approx}> 0.8 AU, this turbulent heating prescription contains all of the necessary physical mechanisms needed to reproduce the empirically estimated proton-to-total heating ratio.

Howes, G. G. [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States)

2011-09-01T23:59:59.000Z

54

REDUCTION OF DRIFT EFFECTS DUE TO SOLAR WIND TURBULENCE  

SciTech Connect (OSTI)

Gradient and curvature drift play a key role in the modulation of cosmic rays. Reduction in the drift coefficient due to turbulence has been demonstrated unambiguously through direct numerical simulations, but a theory that can explain these results is still lacking. We introduce a parameterized form of the drift coefficient based on direct numerical simulations and show that good agreement with observed proton energy spectra at Earth can be found when it is used in a numerical modulation model. We show that the turbulence ultrascale, for which no observations currently exist, plays an important role in drift reduction. The magnitude at Earth and spatial dependence of this quantity required to fit cosmic-ray observations at Earth are argued to be plausible based on the required properties of the two-dimensional turbulence spectrum at large scales.

Burger, R. A.; Visser, D. J. [Unit for Space Physics, North-West University, 2520 Potchefstroom (South Africa)

2010-12-10T23:59:59.000Z

55

Variability of Load and Net Load in Case of Large Scale Distributed Wind Power  

SciTech Connect (OSTI)

Large scale wind power production and its variability is one of the major inputs to wind integration studies. This paper analyses measured data from large scale wind power production. Comparisons of variability are made across several variables: time scale (10-60 minute ramp rates), number of wind farms, and simulated vs. modeled data. Ramp rates for Wind power production, Load (total system load) and Net load (load minus wind power production) demonstrate how wind power increases the net load variability. Wind power will also change the timing of daily ramps.

Holttinen, H.; Kiviluoma, J.; Estanqueiro, A.; Gomez-Lazaro, E.; Rawn, B.; Dobschinski, J.; Meibom, P.; Lannoye, E.; Aigner, T.; Wan, Y. H.; Milligan, M.

2011-01-01T23:59:59.000Z

56

Energy Storage on the Grid and the Short-term Variability of Wind.  

E-Print Network [OSTI]

??Wind generation presents variability on every time scale, which must be accommodated by the electric grid. Limited quantities of wind power can be successfully integrated… (more)

Hittinger, Eric Stephen

2012-01-01T23:59:59.000Z

57

A Model of Turbulence in Magnetized Plasmas: Implications for the Dissipation Range in the Solar Wind  

E-Print Network [OSTI]

This paper studies the turbulent cascade of magnetic energy in weakly collisional magnetized plasmas. A cascade model is presented, based on the assumptions of local nonlinear energy transfer in wavenumber space, critical balance between linear propagation and nonlinear interaction times, and the applicability of linear dissipation rates for the nonlinearly turbulent plasma. The model follows the nonlinear cascade of energy from the driving scale in the MHD regime, through the transition at the ion Larmor radius into the kinetic Alfven wave regime, in which the turbulence is dissipated by kinetic processes. The turbulent fluctuations remain at frequencies below the ion cyclotron frequency due to the strong anisotropy of the turbulent fluctuations, k_parallel cyclotron damping. The conditions under which the gyrokinetic cascade reaches the ion cyclotron frequency are established. Cascade model solutions imply that collisionless damping provides a natural explanation for the observed range of spectral indices in the dissipation range of the solar wind. The dissipation range spectrum is predicted to be an exponential fall off; the power-law behavior apparent in observations may be an artifact of limited instrumental sensitivity. The cascade model is motivated by a programme of gyrokinetic simulations of turbulence and particle heating in the solar wind.

Gregory G. Howes; Steven C. Cowley; William Dorland; Gregory W. Hammett; Eliot Quataert; Alexander A. Schekochihin

2007-07-20T23:59:59.000Z

58

NONLINEAR AERODYNAMIC ANALYSIS OF BRIDGES UNDER TURBULENT WINDS: THE NEW FRONTIER IN BRIDGE  

E-Print Network [OSTI]

NONLINEAR AERODYNAMIC ANALYSIS OF BRIDGES UNDER TURBULENT WINDS: THE NEW FRONTIER IN BRIDGE AERODYNAMICS Xinzhong Chen , Ahsan Kareem and Fred L. Haan, Jr. ¡ Department of Civil Engineering. These approaches are limited to linear structures in which nonlinearities in aerodynamic forces are ignored

Kareem, Ahsan

59

Quasilinear Evolution of Kinetic Alfven Wave Turbulence and Perpendicular Ion Heating in the Solar Wind  

E-Print Network [OSTI]

It is shown that the quasi-linear evolution of ion and electron distribution functions as result of wave-particle interaction of Kinetic Alfven Waves in the turbulent solar wind plasma leads to instability of long wavelength electromagnetic cyclotron waves and to an increase of the ion temperature perpendicular to the magnetic field.

Rudakov, L; Ganguli, G; Mithaiwala, M

2010-01-01T23:59:59.000Z

60

An anisotropic-Alfvenic-turbulence-based solar wind model with proton temperature anisotropy  

E-Print Network [OSTI]

How the solar wind is accelerated to its supersonic speed is intimately related to how it is heated. Mechanisms based on ion-cyclotron resonance have been successful in explaining a large number of observations, those concerning the significant ion temperature anisotropy above coronal holes in particular. However, they suffer from the inconsistency with turbulence theory which says that the turbulent cascade in a low-beta medium like the solar corona should proceed in the perpendicular rather than the parallel direction, meaning that there is little energy in the ion gyro-frequency range for ions to absorb via ion-cyclotron resonance. Recently a mechanism based on the interaction between the solar wind particles and the anisotropic turbulence has been proposed, where the perpendicular proton energy addition is via the stochastic heating (Chandran et al. 2011). We extend this promising mechanism by properly accounting for the effect of proton temperature anisotropy on the propagation of Alfven waves, for the r...

Li, Bo

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "turbulence wind variability" 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

Anisotropic MHD Turbulence in the Interstellar Medium and Solar Wind  

E-Print Network [OSTI]

in k-space Energy cascade rate: (k) k E(k) { Energy spectrum: = constant E(k)dk = total energy = 5;Globally isotropic 2D energy spectrum (logarithmic contours) +0 #12;Current sheet formation intense current. Bhattacharjee, K. Germaschewski S. Galtier #12;Outline · Introduction · Global anisotropy: weak MHD turbulence

Ng, Chung-Sang

62

Atmospheric and Wake Turbulence Impacts on Wind Turbine Fatigue Loading: Preprint  

SciTech Connect (OSTI)

Large-eddy simulations of atmospheric boundary layers under various stability and surface roughness conditions are performed to investigate the turbulence impact on wind turbines. In particular, the aeroelastic responses of the turbines are studied to characterize the fatigue loading of the turbulence present in the boundary layer and in the wake of the turbines. Two utility-scale 5 MW turbines that are separated by seven rotor diameters are placed in a 3 km by 3 km by 1 km domain. They are subjected to atmospheric turbulent boundary layer flow and data is collected on the structural response of the turbine components. The surface roughness was found to increase the fatigue loads while the atmospheric instability had a small influence. Furthermore, the downstream turbines yielded higher fatigue loads indicating that the turbulent wakes generated from the upstream turbines have significant impact.

Lee, S.; Churchfield, M.; Moriarty, P.; Jonkman, J.; Michalakes, J.

2011-12-01T23:59:59.000Z

63

Turbulence effects on the wake flow and power production of a horizontal-axis wind turbine  

Science Journals Connector (OSTI)

Abstract This study experimentally investigated the effects of ambient turbulence on the wake flows and power production of a horizontal-axis wind turbine. The approaching flows included low-turbulence smooth flow and grid-generated turbulent flow. The profiles of time-averaged velocity, turbulence intensity and Reynolds stress from the intermediate to the far-wake regions were measured and compared for smooth and turbulent flows. Based on the measured data, prediction models for the centerline velocity deficit, turbulence intensity, wake radius and velocity profile were proposed. In addition, the experimental results showed that the power productions in the grid-generated turbulent flows were slightly higher than that in the smooth flow. But the power loss due to the velocity deficit in the wake flow was larger than 50% when the downwind distance was less than 12D (D is the rotor diameter). An empirical relation between the power production and the downwind distance x and lateral distance y was proposed.

Chia-Ren Chu; Pei-Hung Chiang

2014-01-01T23:59:59.000Z

64

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

65

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

66

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

67

A study of clear-air turbulence from detailed wind profiles over Cape Kennedy, Florida  

E-Print Network [OSTI]

and Panofsky (oa. cit. ) derived a CAT Index (I) which is proportional to the energy of the vertical component of turbulence. This expression is given by 2 I = (AV) (I - Ri/Ri . ) where QV is the magnitude of the vector difference in wind velocity over a... and energy to be felt as CAT could be generated. They analyzed 17 FPS-16 radar/Jimsphere wind profiles under conditions of weak anticyclonic flow. From their analysis, they estimated a functional relationship between Ri and the thickness, L, of the layer...

Blackburn, James Harvey

2012-06-07T23:59:59.000Z

68

Observation of Turbulent Intermittency Scaling with Magnetic Helicity in an MHD Plasma Wind Tunnel  

Science Journals Connector (OSTI)

The intermittency in turbulent magnetic field fluctuations has been observed to scale with the amount of magnetic helicity injected into a laboratory plasma. An unstable spheromak injected into the MHD wind tunnel of the Swarthmore Spheromak Experiment displays turbulent magnetic and plasma fluctuations as it relaxes into a Taylor state. The level of intermittency of this turbulence is determined by finding the flatness of the probability distribution function of increments for magnetic pickup coil fluctuations B?(t). The intermittency increases with the injected helicity, but spectral indices are unaffected by this variation. While evidence is provided which supports the hypothesis that current sheets and reconnection sites are related to the generation of this intermittent signal, the true nature of the observed intermittency remains unknown.

D.?A. Schaffner; A. Wan; M.?R. Brown

2014-04-25T23:59:59.000Z

69

The slow-mode nature of compressible wave power in solar wind turbulence  

E-Print Network [OSTI]

We use a large, statistical set of measurements from the Wind spacecraft at 1 AU, and supporting synthetic spacecraft data based on kinetic plasma theory, to show that the compressible component of inertial range solar wind turbulence is primarily in the kinetic slow mode. The zero-lag cross correlation C(delta n, delta B_parallel) between proton density fluctuations delta n and the field-aligned (compressible) component of the magnetic field delta B_parallel is negative and close to -1. The typical dependence of C(delta n,delta B_parallel) on the ion plasma beta_i is consistent with a spectrum of compressible wave energy that is almost entirely in the kinetic slow mode. This has important implications for both the nature of the density fluctuation spectrum and for the cascade of kinetic turbulence to short wavelengths, favoring evolution to the kinetic Alfven wave mode rather than the (fast) whistler mode.

Howes, G G; Klein, K G; Chen, C H K; Salem, C S; TenBarge, J M

2011-01-01T23:59:59.000Z

70

The Role of Turbulence in Coronal Heating and Solar Wind Expansion  

E-Print Network [OSTI]

Plasma in the Sun's hot corona expands into the heliosphere as a supersonic and highly magnetized solar wind. This paper provides an overview of our current understanding of how the corona is heated and how the solar wind is accelerated. Recent models of magnetohydrodynamic turbulence have progressed to the point of successfully predicting many observed properties of this complex, multi-scale system. However, it is not clear whether the heating in open-field regions comes mainly from the dissipation of turbulent fluctuations that are launched from the solar surface, or whether the chaotic "magnetic carpet" in the low corona energizes the system via magnetic reconnection. To help pin down the physics, we also review some key observational results from ultraviolet spectroscopy of the collisionless outer corona.

Cranmer, S R; Miralles, M P; Raymond, J C; Strachan, L; Tian, H; Woolsey, L N

2014-01-01T23:59:59.000Z

71

Magnetohydrodynamic simulation of the radial evolution and stream structure of solar-wind turbulence  

Science Journals Connector (OSTI)

We present a unified interpretation of observations of interplanetary fluctuations in terms of nearly incompressible magnetohyrodynamics. Incompressive effects explain the rapid evolution of turbulence in slow wind containing the heliospheric current sheet. The relative constancy of the spectrum of ‘‘inward propagating’’ fluctuations compared to the rapid decline in ‘‘outward’’ fluctuations results from incompressive spectral transfer combined with strong dissipation of the outward fluctuations. Secondary compressive effects account for nearly pressure-balanced structures and the density fluctuation levels.

D. Aaron Roberts; Sanjoy Ghosh; Melvyn L. Goldstein; William H. Mattheaus

1991-12-30T23:59:59.000Z

72

Wind reversals in turbulent Rayleigh-Benard convection  

E-Print Network [OSTI]

The phenomenon of irregular cessation and subsequent reversal of the large-scale circulation in turbulent Rayleigh-B\\'enard convection is theoretically analysed. The force and thermal balance on a single plume detached from the thermal boundary layer yields a set of coupled nonlinear equations, whose dynamics is related to the Lorenz equations. For Prandtl and Rayleigh numbers in the range $10^{-2} \\leq \\Pr \\leq 10^{3}$ and $10^{7} \\leq \\Ra \\leq 10^{12}$, the model has the following features: (i) chaotic reversals may be exhibited at Ra $\\geq 10^{7}$; (ii) the Reynolds number based on the root mean square velocity scales as $\\Re_{rms} \\sim \\Ra^{[0.41 ... 0.47]}$ (depending on Pr), and as $\\Re_{rms} \\sim \\Pr^{-[0.66 ... 0.76]}$ (depending on Ra); and (iii) the mean reversal frequency follows an effective scaling law $\\omega / (\

Francisco Fontenele Araujo; S. Grossmann; D. Lohse

2005-08-29T23:59:59.000Z

73

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

74

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

75

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

76

Nonlinear interaction of proton whistler with kinetic Alfvén wave to study solar wind turbulence  

SciTech Connect (OSTI)

This paper presents the nonlinear interaction between small but finite amplitude kinetic Alfvén wave (KAW) and proton whistler wave using two-fluid model in intermediate beta plasma, applicable to solar wind. The nonlinearity is introduced by modification in the background density. This change in density is attributed to the nonlinear ponderomotive force due to KAW. The solutions of the model equations, governing the nonlinear interaction (and its effect on the formation of localized structures), have been obtained using semi-analytical method in solar wind at 1AU. It is concluded that the KAW properties significantly affect the threshold field required for the filament formation and their critical size (for proton whistler). The magnetic and electric field power spectra have been obtained and their relevance with the recent observations of solar wind turbulence by Cluster spacecraft has been pointed out.

Goyal, R.; Sharma, R. P. [Centre for Energy Studies, Indian Institute of Technology, Delhi-110016 (India)] [Centre for Energy Studies, Indian Institute of Technology, Delhi-110016 (India); Goldstein, M. L. [NASA Goddard Space Flight Centre, Code 673, Greenbelt, Maryland 20771 (United States)] [NASA Goddard Space Flight Centre, Code 673, Greenbelt, Maryland 20771 (United States); Dwivedi, N. K. [Austrian Academy of Sciences, Space Research Institute, Schmiedlstrasse 6, 8042 Graz (Austria)] [Austrian Academy of Sciences, Space Research Institute, Schmiedlstrasse 6, 8042 Graz (Austria)

2013-12-15T23:59:59.000Z

77

Optimization of Wind Power and Its Variability With a Computational Intelligence Approach  

E-Print Network [OSTI]

Optimization of Wind Power and Its Variability With a Computational Intelligence Approach Zijun is presented for maximizing the generation of wind power while minimizing its variability. In the optimization model, data-driven approaches are used to model the wind-power generation process based on industrial

Kusiak, Andrew

78

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

79

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

80

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

Note: This page contains sample records for the topic "turbulence wind variability" 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

Kinetic cascade beyond MHD of solar wind turbulence in two-dimensional hybrid simulations  

E-Print Network [OSTI]

The nature of solar wind turbulence in the dissipation range at scales much smaller than the large MHD scales remains under debate. Here a two-dimensional model based on the hybrid code abbreviated as A.I.K.E.F. is presented, which treats massive ions as particles obeying the kinetic Vlasov equation and massless electrons as a neutralizing fluid. Up to a certain wavenumber in the MHD regime, the numerical system is initialized by assuming a superposition of isotropic Alfv\\'en waves with amplitudes that follow the empirically confirmed spectral law of Kolmogorov. Then turbulence develops and energy cascades into the dispersive spectral range, where also dissipative effects occur. Under typical solar wind conditions, weak turbulence develops as a superposition of normal modes in the kinetic regime. Spectral analysis in the direction parallel to the background magnetic field reveals a cascade of left-handed Alfv\\'en/ion-cyclotron waves up to wave vectors where their resonant absorption sets in, as well as a cont...

Verscharen, Daniel; Motschmann, Uwe; Müller, Joachim

2012-01-01T23:59:59.000Z

82

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.

83

Validating a Time-Dependent Wave-Turbulence-Driven Model of the Solar Wind  

E-Print Network [OSTI]

Although the mechanisms responsible for heating the Sun's corona and accelerating the solar wind are still being actively investigated, it is largely accepted that photospheric motions provide the energy source and that the magnetic field must play a key role in the process. \\citet{2010ApJ...708L.116V} presented a model for heating and accelerating the solar wind based on the turbulent dissipation of Alfv\\'en waves. We first use a time-dependent model of the solar wind to reproduce one of \\citeauthor{2010ApJ...708L.116V}'s solutions; then we extend its application to the case when the energy equation includes thermal conduction and radiation losses, and the upper chromosphere is part of the computational domain. Using this model, we explore parameter space and describe the characteristics of a fast-solar-wind solution. We discuss how this formulation may be applied to a 3D MHD model of the coron a and solar wind \\citep{2009ApJ...690..902L}.

Lionello, Roberto; Downs, Cooper; Linker, Jon A; Miki?, Zoran; Verdini, Andrea

2014-01-01T23:59:59.000Z

84

Chaotic mean wind in turbulent thermal convection and long-term correlations in solar activity  

E-Print Network [OSTI]

It is shown that correlation function of the mean wind velocity in a turbulent thermal convection (Rayleigh number $Ra \\sim 10^{11}$) exhibits exponential decay with a very long correlation time, while corresponding largest Lyapunov exponent is certainly positive. These results together with the reconstructed phase portrait indicate presence of a chaotic component in the examined mean wind. Telegraph approximation is also used to study relative contribution of the chaotic and stochastic components to the mean wind fluctuations and an equilibrium between these components has been studied. Since solar activity is based on the thermal convection processes, it is reasoned that the observed solar activity long-term correlations can be an imprint of the mean wind chaotic properties. In particular, correlation function of the daily sunspots number exhibits exponential decay with a very long correlation time and corresponding largest Lyapunov exponent is certainly positive, also relative contribution of the chaotic and stochastic components follows the same pattern as for the convection mean wind.

A. Bershadskii

2009-08-27T23:59:59.000Z

85

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 Båserud; Martin Flügge; Anak Bhandari; Joachim Reuder

2014-01-01T23:59:59.000Z

86

Determining the influence of wind-wave breaking on the dissipation of the turbulent kinetic energy in the upper ocean and on the dependence of the turbulent kinetic energy on the stage of wind-wave development  

Science Journals Connector (OSTI)

New experimental data that make it possible to explain and predict the observed variability of turbulent-energy dissipation in the upper ocean are discussed. ... For this purpose, the dependence of the energy dis...

S. A. Kitaigorodskii

2009-06-01T23:59:59.000Z

87

Empirical Analysis of the Variability of Wind Generation in India: Implications for Grid Integration  

E-Print Network [OSTI]

variability. For higher penetration rate (30% by energy),curtailment even at high penetration rates. Moreover, iffor various wind penetration rates in this study establishes

Phadke, Amol

2014-01-01T23:59:59.000Z

88

New Report: Integrating Variable Wind Energy into the Grid | Department of  

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

Report: Integrating Variable Wind Energy into the Grid Report: Integrating Variable Wind Energy into the Grid New Report: Integrating Variable Wind Energy into the Grid December 19, 2011 - 2:00pm Addthis The Energy Department and Alstom Grid announce the availability of a new report on integrating wind energy into the electrical grid. | Image source: The Strategies and Decision Support Systems for Integrating Variable Energy Resources in Control Centers for Reliable Grid Operations Report. The Energy Department and Alstom Grid announce the availability of a new report on integrating wind energy into the electrical grid. | Image source: The Strategies and Decision Support Systems for Integrating Variable Energy Resources in Control Centers for Reliable Grid Operations Report. Charlton I. Clark Integration Team Lead, Wind and Water Power Program

89

Kinetic cascade beyond magnetohydrodynamics of solar wind turbulence in two-dimensional hybrid simulations  

Science Journals Connector (OSTI)

The nature of solar windturbulence in the dissipation range at scales much smaller than the large magnetohydrodynamic (MHD) scales remains under debate. Here a two-dimensional model based on the hybrid code abbreviated as A.I.K.E.F. is presented which treats massive ions as particles obeying the kinetic Vlasov equation and massless electrons as a neutralizing fluid. Up to a certain wavenumber in the MHD regime the numerical system is initialized by assuming a superposition of isotropic Alfvén waves with amplitudes that follow the empirically confirmed spectral law of Kolmogorov. Then turbulence develops and energy cascades into the dispersive spectral range where also dissipative effects occur. Under typical solar wind conditions weak turbulence develops as a superposition of normal modes in the kinetic regime. Spectral analysis in the direction parallel to the background magnetic field reveals a cascade of left-handed Alfvén/ion-cyclotron waves up to wave vectors where their resonant absorption sets in as well as a continuing cascade of right-handed fast-mode and whistler waves. Perpendicular to the background field a broad turbulent spectrum is found to be built up of fluctuations having a strong compressive component. Ion-Bernstein waves seem to be possible normal modes in this propagation direction for lower driving amplitudes. Also signatures of short-scale pressure-balanced structures (very oblique slow-mode waves) are found.

D. Verscharen; E. Marsch; U. Motschmann; J. Müller

2012-01-01T23:59:59.000Z

90

1980–2010 Variability in U.K. Surface Wind Climate  

Science Journals Connector (OSTI)

The climate of the northeast Atlantic region comprises substantial decadal variability in storminess. It also exhibits strong inter- and intra-annual variability in extreme high and low wind speed episodes. Here the authors quantify and discuss ...

Nick Earl; Steve Dorling; Richard Hewston; Roland von Glasow

2013-02-01T23:59:59.000Z

91

Grid Impacts of Wind Power Variability: Recent Assessments from a Variety of Utilities in the United States (Presentation)  

SciTech Connect (OSTI)

Presentation for the European Wind Energy Conference held February 27--March 2, 2006, in Athens, Greece, showing grid impacts of wind power variability.

Parsons, B.

2006-03-01T23:59:59.000Z

92

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

93

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

94

May 2013 PSERC Webinar: Managing Wind Variability with Self-Reserves and  

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

May 2013 PSERC Webinar: Managing Wind Variability with May 2013 PSERC Webinar: Managing Wind Variability with Self-Reserves and Responsive Demand May 2013 PSERC Webinar: Managing Wind Variability with Self-Reserves and Responsive Demand April 9, 2013 - 10:40am Addthis The DOE-funded Power Systems Engineering Research Center (PSERC) is offering a free public webinar on managing wind variability in energy production. The webinar will be held Tuesday, May 7, 2013 from 2-3 p.m. No pre-registration is necessary. Using wind power to supply up to 20%, or more, of electrical demand is increasingly popular in policy mandates, yet is relatively untested in terms of actual system and market operations. This presentation will investigate the concept of self-reserves, wherein wind generators withhold a portion of forecasted energy production, via their hour-ahead schedule,

95

On the ""early-time"" evolution of variables relevant to turbulence models for Rayleigh-Taylor instability  

SciTech Connect (OSTI)

We present our progress toward setting initial conditions in variable density turbulence models. In particular, we concentrate our efforts on the BHR turbulence model for turbulent Rayleigh-Taylor instability. Our approach is to predict profiles of relevant parameters before the fully turbulent regime and use them as initial conditions for the turbulence model. We use an idealized model of the mixing between two interpenetrating fluids to define the initial profiles for the turbulence model parameters. Velocities and volume fractions used in the idealized mixing model are obtained respectively from a set of ordinary differential equations modeling the growth of the Rayleigh-Taylor instability and from an idealization of the density profile in the mixing layer. A comparison between predicted initial profiles for the turbulence model parameters and initial profiles of the parameters obtained from low Atwood number three dimensional simulations show reasonable agreement.

Rollin, Bertrand [Los Alamos National Laboratory; Andrews, Malcolm J [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

96

Geographical and seasonal variability of the global “practical” wind resources  

Science Journals Connector (OSTI)

Abstract This paper provides global and seasonal estimates of the “practical” wind power obtained with a 3-D numerical model (GATOR-GCMOM) that dynamically calculates the instantaneous wind power of a modern 5 MW wind turbine at 100-m hub height at each time step. “Practical” wind power is defined as that delivered from wind turbines in high-wind locations (year-average 100-m wind speed ? 7 m/s) over land and near-shore, excluding both polar regions, mountainous, and conflicting land use areas, and including transmission, distribution, and wind farm array losses. We found that seasonal variations in the global practical wind resources are significant. The highest net land plus near-shore capacity factors globally are found during December–January–February and the lowest during June–July–August. The capacity factors in the transitional seasons (March–April–May and September–October–November) are rather similar to one another in terms of geographical patterns and frequency distributions. The yearly-average distributions of capacity factors, whether in terms of geographic patterns or frequency distributions, differ from those in all four seasons, although they are closest to the transitional seasons. Regional practical wind resources are sensitive to seasons and to thresholds in year-average wind speed and bathymetry, but are more than enough to supply local electricity demand in all regions except Japan.

Cristina L. Archer; Mark Z. Jacobson

2013-01-01T23:59:59.000Z

97

Wake Turbulence of Two NREL 5-MW Wind Turbines Immersed in a Neutral Atmospheric Boundary-Layer Flow  

E-Print Network [OSTI]

The fluid dynamics video considers an array of two NREL 5-MW turbines separated by seven rotor diameters in a neutral atmospheric boundary layer (ABL). The neutral atmospheric boundary-layer flow data were obtained from a precursor ABL simulation using a Large-Eddy Simulation (LES) framework within OpenFOAM. The mean wind speed at hub height is 8m/s, and the surface roughness is 0.2m. The actuator line method (ALM) is used to model the wind turbine blades by means of body forces added to the momentum equation. The fluid dynamics video shows the root and tip vortices emanating from the blades from various viewpoints. The vortices become unstable and break down into large-scale turbulent structures. As the wakes of the wind turbines advect further downstream, smaller-scale turbulence is generated. It is apparent that vortices generated by the blades of the downstream wind turbine break down faster due to increased turbulence levels generated by the wake of the upstream wind turbine.

Bashioum, Jessica L; Schmitz, Sven; Duque, Earl P N

2013-01-01T23:59:59.000Z

98

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

99

POSSIBLE EVIDENCE OF ALFVEN-CYCLOTRON WAVES IN THE ANGLE DISTRIBUTION OF MAGNETIC HELICITY OF SOLAR WIND TURBULENCE  

SciTech Connect (OSTI)

The fluctuating magnetic helicity is considered an important parameter in diagnosing the characteristic modes of solar wind turbulence. Among them is the Alfven-cyclotron wave, which is probably responsible for the solar wind plasma heating, but has not yet been identified from the magnetic helicity of solar wind turbulence. Here, we present the possible signatures of Alfven-cyclotron waves in the distribution of magnetic helicity as a function of {theta}{sub VB}, which is the angle between the solar wind velocity and local mean magnetic field. We use magnetic field data from the STEREO spacecraft to calculate the {theta}{sub VB} distribution of the normalized reduced fluctuating magnetic helicity {sigma}{sub m}. We find a dominant negative {sigma}{sub m} for 1 s < p < 4 s (p is time period) and for {theta}{sub VB} < 30 deg. in the solar wind outward magnetic sector, and a dominant positive {sigma}{sub m} for 0.4 s < p < 4 s and for {theta}{sub VB}>150 deg. in the solar wind inward magnetic sector. These features of {sigma}{sub m} appearing around the Doppler-shifted ion-cyclotron frequencies may be consistent with the existence of Alfven-cyclotron waves among the outward propagating fluctuations. Moreover, right-handed polarized waves at larger propagation angles, which might be kinetic Alfven waves or whistler waves, have also been identified on the basis of the {sigma}{sub m} features in the angular range 40 deg. < {theta}{sub VB} < 140 deg. Our findings suggest that Alfven-cyclotron waves (together with other wave modes) play a prominent role in turbulence cascading and plasma heating of the solar wind.

He Jiansen; Tu Chuanyi; Yao Shuo; Tian Hui [Department of Geophysics, Peking University, Beijing 100871 (China); Marsch, Eckart, E-mail: jshept@gmail.com [Max-Planck-Institut fuer Sonnensystemforschung, 37191 Katlenburg-Lindau (Germany)

2011-04-20T23:59:59.000Z

100

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

Note: This page contains sample records for the topic "turbulence wind variability" 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

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

102

Impact of Wind Generation Variability on Voltage Profile of Radial Power Systems  

Science Journals Connector (OSTI)

This paper provides the results of a study conducted to assess the impacts of the "wind generation variability" on the voltage profile in a small-scale radial power system. The power network has been modeled using one of the well-known simulation programs ... Keywords: Wind Generation, Voltage Profile, Power Grids, Voltage Impacts, Minimum Singular Value, SSV index

M. O. Alruwaili; M. Y. Vaziri; S. Vadhva; S. Vaziri

2013-04-01T23:59:59.000Z

103

Abstract--The variability and non-dispatchable nature of wind and solar energy production presents  

E-Print Network [OSTI]

1 Abstract--The variability and non-dispatchable nature of wind and solar energy production needed for a variety of energy storage applications can be found in [6]. Wind and solar power variations, energy storage can be a viable solution to balance energy production against its consumption. This paper

104

Numerical simulation of interannual and interdecadal variability of surface wind over the tropical Pacific  

Science Journals Connector (OSTI)

A global atmospheric general circulation model (L9R15 AGCMs) forced by COADS SST was integrated from 1945 to 1993. Interannual and interdecadal variability of the simulated surface wind over the tropical Pacific ...

Wu Ai-ming; Zhao Yong-ping; Bai Xue-zhi…

2002-03-01T23:59:59.000Z

105

On currents, internal and inertial waves in a stratified ocean due to variable winds. Part 1  

Science Journals Connector (OSTI)

The response of a continuously stratified viscous ocean to a variable wind air pressure field has been studied during recent years by means of analytical methods. This requires the assumption of constant eddy ...

Prof. Dr. W. Krauss

1976-01-01T23:59:59.000Z

106

On currents, internal and inertial waves in a stratified ocean due to variable winds. Part 2  

Science Journals Connector (OSTI)

The response of a continuously stratified viscous ocean to a variable wind and air pressure field has been studied during recent years by means of analytical methods. This requires the assumption of consntant ...

Prof. Dr. W. Krauss

1976-01-01T23:59:59.000Z

107

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

108

Variable enstrophy flux and energy spectrum in two-dimensional turbulence with Ekman friction  

E-Print Network [OSTI]

Experiments and numerical simulations reveal that in the forward cascade regime, the energy spectrum of two-dimensional turbulence with Ekman friction deviates from Kraichnan's prediction of $k^{-3}$ power spectrum. In this letter we explain this observation using an analytic model based on variable enstrophy flux arising due to Ekman friction. We derive an expression for the enstrophy flux which exhibits a logarithmic dependence in the inertial range for the Ekman-friction dominated flows. The energy spectrum obtained using this enstrophy flux shows a power law scaling for large Reynolds number and small Ekman friction, but has an exponential behaviour for large Ekman friction and relatively small Reynolds number.

Mahendra K. Verma

2012-03-23T23:59:59.000Z

109

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

110

Wind Levelized Cost of Energy: A Comparison of Technical and Financing Input Variables  

SciTech Connect (OSTI)

The expansion of wind power capacity in the United States has increased the demand for project development capital. In response, innovative approaches to financing wind projects have emerged and are proliferating in the U.S. renewable energy marketplace. Wind power developers and financiers have become more efficient and creative in structuring their financial relationships, and often tailor them to different investor types and objectives. As a result, two similar projects may use very different cash flows and financing arrangements, which can significantly vary the economic competitiveness of wind projects. This report assesses the relative impact of numerous financing, technical, and operating variables on the levelized cost of energy (LCOE) associated with a wind project under various financing structures in the U.S. marketplace. Under this analysis, the impacts of several financial and technical variables on the cost of wind electricity generation are first examined individually to better understand the relative importance of each. Then, analysts examine a low-cost and a high-cost financing scenario, where multiple variables are modified simultaneously. Lastly, the analysis also considers the impact of a suite of financial variables versus a suite of technical variables.

Cory, K.; Schwabe, P.

2009-10-01T23:59:59.000Z

111

Simplified life cycle approach: GHG variability assessment for onshore wind electricity based on Monte-Carlo simulations  

E-Print Network [OSTI]

Simplified life cycle approach: GHG variability assessment for onshore wind electricity based in the literature. In the special case of greenhouses gases (GHG) from wind power electricity, the LCA results performances with a simplified life cycle approach. Variability of GHG performances of onshore wind turbines

Paris-Sud XI, Université de

112

Wind- versus Eddy-Forced Regional Sea Level Trends and Variability in the North Pacific Ocean  

Science Journals Connector (OSTI)

Regional sea level trend and variability in the Pacific Ocean have often been considered to be induced by low-frequency surface wind changes. In this study, we demonstrate that significant sea level trend and variability can also be generated by ...

Bo Qiu; Shuiming Chen; Lixin Wu; Shinichiro Kida

113

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

114

Temporal and spatial variability of wind resources in the United States as derived from the Climate Forecast System Reanalysis  

Science Journals Connector (OSTI)

This study examines the spatial and temporal variability of wind speed at 80 m above ground (the average hub height of most modern wind turbines) in the contiguous United States using Climate Forecast System Reanalysis (CFSR) data from 1979 to ...

Lejiang Yu; Shiyuan Zhong; Xindi Bian; Warren E. Heilman

115

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

Science Journals Connector (OSTI)

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

A. V. Garmashov; A. B. Polonskii

2011-12-01T23:59:59.000Z

116

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

117

Empirical Analysis of the Variability of Wind Generation in India: Implications for Grid Integration  

SciTech Connect (OSTI)

We analyze variability in load and wind generation in India to assess its implications for grid integration of large scale wind projects using actual wind generation and load data from two states in India, Karnataka and Tamil Nadu. We compare the largest variations in load and net load (load ?wind, i.e., load after integrating wind) that the generation fleet has to meet. In Tamil Nadu, where wind capacity is about 53percent of the peak demand, we find that the additional variation added due to wind over the current variation in load is modest; if wind penetration reaches 15percent and 30percent by energy, the additional hourly variation is less than 0.5percent and 4.5percent of the peak demand respectively for 99percent of the time. For wind penetration of 15percent by energy, Tamil Nadu system is found to be capable of meeting the additional ramping requirement for 98.8percent of the time. Potential higher uncertainty in net load compared to load is found to have limited impact on ramping capability requirements of the system if coal plants can me ramped down to 50percent of their capacity. Load and wind aggregation in Tamil Nadu and Karnataka is found to lower the variation by at least 20percent indicating the benefits geographic diversification. These findings suggest modest additional flexible capacity requirements and costs for absorbing variation in wind power and indicate that the potential capacity support (if wind does not generate enough during peak periods) may be the issue that has more bearing on the economics of integrating wind

Phadke, Amol; Abhyankar, NIkit; Rao, Poorvi

2014-06-17T23:59:59.000Z

118

Using the Twentieth Century Reanalysis to assess climate variability for the European wind industry  

E-Print Network [OSTI]

We characterise the long-term variability of European near-surface wind speeds using 140 years of data from the Twentieth Century Reanalysis (20CR), and consider the potential of such long-baseline climate data sets for wind energy applications. The low resolution of the 20CR would severely restrict its use on its own for wind farm site-screening. We therefore perform a simple statistical calibration to link it to the higher-resolution ERA-Interim data set (ERAI), such that the adjusted 20CR data has the same wind speed distribution at each location as ERAI during their common period. Using this corrected 20CR data set, wind speeds and variability are characterised in terms of the long-term mean, standard deviation, and corresponding trends. Many regions of interest show extremely weak trends on century timescales, but contain large multidecadal variability. Variations in the form of the wind speed distribution are assessed in terms of its deciles; we find that the commonly-used Weibull distribution often pro...

Bett, Philip E; Clark, Robin T

2014-01-01T23:59:59.000Z

119

Turbulence  

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

Turbulence Turbulence in Alcator C-Mod and Wendelstein 7-AS plasmas during controlled confinement transitions N.P.Basse, E.M.Edlund, C.L.Fiore, M.J.Greenwald, A.E.Hubbard, J.W.Hughes, J.H.Irby, G.J.Kramer 1 , L.Lin, Y.Lin, A.G.Lynn 2 , E.S.Marmar, D.R.Mikkelsen 1 , D.Mossessian, P.E.Phillips 2 , M.Porkolab, J.E.Rice, W.L.Rowan 2 , J.A.Snipes, J.L.Terry, S.M.Wolfe, S.J.Wukitch, K.Zhurovich, S.Zoletnik 3 and the C-Mod and W7-AS 4 Teams MIT Plasma Science and Fusion Center, Cambridge, USA 1 Princeton Plasma Physics Laboratory, Princeton, USA 2 University of Texas at Austin, Austin, USA 3 KFKI-RMKI, EURATOM Association, Budapest, Hungary 4 Max-Planck-Institut f¨ ur Plasmaphysik, EURATOM Association, Greifswald, Germany At certain values of the edge rotational transform, ι a = 1/q a , the confinement time of plasmas in the Wendelstein 7-AS (W7-AS) stellarator was found to

120

Predicting the Energy Output of Wind Farms Based on Weather Data: Important Variables and their Correlation  

E-Print Network [OSTI]

Wind energy plays an increasing role in the supply of energy world-wide. The energy output of a wind farm is highly dependent on the weather condition present at the wind farm. If the output can be predicted more accurately, energy suppliers can coordinate the collaborative production of different energy sources more efficiently to avoid costly overproductions. With this paper, we take a computer science perspective on energy prediction based on weather data and analyze the important parameters as well as their correlation on the energy output. To deal with the interaction of the different parameters we use symbolic regression based on the genetic programming tool DataModeler. Our studies are carried out on publicly available weather and energy data for a wind farm in Australia. We reveal the correlation of the different variables for the energy output. The model obtained for energy prediction gives a very reliable prediction of the energy output for newly given weather data.

Vladislavleva, Katya; Neumann, Frank; Wagner, Markus

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "turbulence wind variability" 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

Tomographic Simulations of Accretion Disks in Cataclysmic Variables - Flickering and Wind  

E-Print Network [OSTI]

Both continuum and emission line flickering are phenomena directly associated with the mass accretion process. In this work we simulate accretion disk Doppler maps including the effects of winds and flickering flares. Synthetic flickering Doppler maps are calculated and the effect of the flickering parameters on the maps is explored. Jets and winds occur in many astrophysical objects where accretion disks are present. Jets are generally absent among the cataclysmic variables (CVs), but there is evidence of mass loss by wind in many objects. CVs are ideal objects to study accretion disks and consequently to study the wind associated with these disks. We also present simulations of accretion disks including the presence of a wind with orbital phase resolution. Synthetic H-alpha line profiles in the optical region are obtained and their corresponding Doppler maps are calculated. The effect of the wind simulation parameters on the wind line profiles is also explored. From this study we verified that optically thick lines and/or emission by diffuse material into the primary Roche lobe are necessary to generate single peaked line profiles, often seen in CVs. The future accounting of these effects is suggested for interpreting Doppler tomography reconstructions.

Fabiola M. A. Ribeiro; Marcos P. Diaz

2007-11-22T23:59:59.000Z

122

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

123

Turbulence-induced resonance vibrations cause pollen release in wind-pollinated Plantago lanceolata L. (Plantaginaceae)  

Science Journals Connector (OSTI)

...00, stamens were filmed and wind velocity was sampled over 9-min...the analysis. Fluctuations in wind velocity (u, v, w) were...energy for the fluctuations. Power spectral densities (PSDs...displacements and 12.5 Hz for wind velocities. The acceleration...

2014-01-01T23:59:59.000Z

124

Ion kinetic energy conservation and magnetic field strength constancy in multi-fluid solar wind Alfv\\'enic turbulence  

E-Print Network [OSTI]

We investigate properties of the plasma fluid motion in the large amplitude low frequency fluctuations of highly Alfv\\'enic fast solar wind. We show that protons locally conserve total kinetic energy when observed from an effective frame of reference comoving with the fluctuations. For typical properties of the fast wind, this frame can be reasonably identified by alpha particles, which, owing to their drift with respect to protons at about the Alfv\\'en speed along the magnetic field, do not partake in the fluid low frequency fluctuations. Using their velocity to transform proton velocity into the frame of Alfv\\'enic turbulence, we demonstrate that the resulting plasma motion is characterized by a constant absolute value of the velocity, zero electric fields, and aligned velocity and magnetic field vectors as expected for unidirectional Alfv\\'enic fluctuations in equilibrium. We propose that this constraint, via the correlation between velocity and magnetic field in Alfv\\'enic turbulence, is at the origin of ...

Matteini, L; Pantellini, F; Velli, M; Schwartz, S J

2015-01-01T23:59:59.000Z

125

Petascale Simulations of Inhomogeneous Alfvén Turbulence in the Solar Wind  

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

A snapshot of turbulent magnetic field lines (red) inside a coronal hole that expands from a small patch on the solar surface to 5 solar radii A snapshot of turbulent magnetic field lines (red) inside a coronal hole that expands from a small patch on the solar surface to 5 solar radii A snapshot of turbulent magnetic field lines (red) inside a coronal hole that expands from a small patch on the solar surface to 5 solar radii. Alfven waves (AW), launched by convective motions on the photosphere, propagate in the inhomogeneous Solar atmosphere producing primary reflected waves that interact non-linearly with the outward waves, driving a turbulent cascade. This cascade continues with secondary reflections in a very complex interplay between wave reflections and nonlinear interactions. Selected slices across the simulation domain show contours of plasma current, indicating the generation of small scale structures where the

126

The market value of variable renewables: The effect of solar wind power variability on their relative price  

Science Journals Connector (OSTI)

Abstract This paper provides a comprehensive discussion of the market value of variable renewable energy (VRE). The inherent variability of wind speeds and solar radiation affects the price that VRE generators receive on the market (market value). During windy and sunny times the additional electricity supply reduces the prices. Because the drop is larger with more installed capacity, the market value of VRE falls with higher penetration rate. This study aims to develop a better understanding on how the market value with penetration, and how policies and prices affect the market value. Quantitative evidence is derived from a review of published studies, regression analysis of market data, and the calibrated model of the European electricity market EMMA. We find the value of wind power to fall from 110% of the average power price to 50–80% as wind penetration increases from zero to 30% of total electricity consumption. For solar power, similarly low value levels are reached already at 15% penetration. Hence, competitive large-scale renewable deployment will be more difficult to accomplish than as many anticipate.

Lion Hirth

2013-01-01T23:59:59.000Z

127

SELF-CONSISTENT MODEL OF THE INTERSTELLAR PICKUP PROTONS, ALFVENIC TURBULENCE, AND CORE SOLAR WIND IN THE OUTER HELIOSPHERE  

SciTech Connect (OSTI)

A self-consistent model of the interstellar pickup protons, the slab component of the Alfvenic turbulence, and core solar wind (SW) protons is presented for r {>=} 1 along with the initial results of and comparison with the Voyager 2 (V2) observations. Two kinetic equations are used for the pickup proton distribution and Alfvenic power spectral density, and a third equation governs SW temperature including source due to the Alfven wave energy dissipation. A fraction of the pickup proton free energy, f{sub D} , which is actually released in the waveform during isotropization, is taken from the quasi-linear consideration without preexisting turbulence, whereas we use observations to specify the strength of the large-scale driving, C{sub sh}, for turbulence. The main conclusions of our study can be summarized as follows. (1) For C{sub sh} Almost-Equal-To 1-1.5 and f{sub D} Almost-Equal-To 0.7-1, the model slab component agrees well with the V2 observations of the total transverse magnetic fluctuations starting from {approx}8 AU. This indicates that the slab component at low-latitudes makes up a majority of the transverse magnetic fluctuations beyond 8-10 AU. (2) The model core SW temperature agrees well with the V2 observations for r {approx}> 20 AU if f{sub D} Almost-Equal-To 0.7-1. (3) A combined effect of the Wentzel-Kramers-Brillouin attenuation, large-scale driving, and pickup proton generated waves results in the energy sink in the region r {approx}< 10 AU, while wave energy is pumped in the turbulence beyond 10 AU. Without energy pumping, the nonlinear energy cascade is suppressed for r {approx}< 10 AU, supplying only a small energy fraction into the k-region of dissipation by the core SW protons. A similar situation takes place for the two-dimensional turbulence. (4) The energy source due to the resonant Alfven wave damping by the core SW protons is small at heliocentric distances r {approx}< 10 AU for both the slab and the two-dimensional turbulent components. As a result, adiabatic cooling mostly controls the model SW temperature in this region, and the model temperature disagrees with the V2 observations in the region r {approx}< 20 AU.

Gamayunov, Konstantin V.; Zhang Ming; Rassoul, Hamid K. [Department of Physics and Space Sciences, Florida Institute of Technology, Melbourne, FL 32901 (United States); Pogorelov, Nikolai V.; Heerikhuisen, Jacob, E-mail: kgamayunov@fit.edu [Department of Physics and Center for Space Physics and Aeronomic Research, University of Alabama, Huntsville, AL 35899 (United States)

2012-09-20T23:59:59.000Z

128

Rummaging inside the Eskimo's parka: Variable asymmetric PN fast wind and a binary nucleus?  

E-Print Network [OSTI]

We report on high-resolution optical time-series spectroscopy of the central star of the `Eskimo' planetary nebula NGC~2392. Datasets were secured with the ESO 2.3m in 2006 March and CFHT 3.6m in 2010 March to diagnose the fast wind and photospheric properties of the central star. The HeI and HeII recombination lines reveal evidence for clumping and temporal structures in the fast wind that are erratically variable on timescales down to ~ 30 min. (i.e. comparable to the characteristic wind flow time). We highlight changes in the overall morphology of the wind lines that cannot plausibly be explained by line-synthesis model predictions with a spherically homogeneous wind. Additionally we present evidence that the UV line profile morphologies support the notion of a high-speed, high-ionization polar wind in NGC~2392. Analyses of deep-seated, near-photospheric absorption lines reveals evidence for low-amplitude radial velocity shifts. Fourier analysis points tentatively to a ~ 0.12-d modulation in the radial vel...

Prinja, Raman

2014-01-01T23:59:59.000Z

129

Empirical Analysis of the Variability of Wind Generation in India: Implications for Grid Integration  

E-Print Network [OSTI]

Operations: A Review of Wind Integration Studies to Date. ”Analysis of Impacts of Wind Integration in the Tamil Nadu2009. “Calculating Wind Integration Costs: Separating Wind

Phadke, Amol

2014-01-01T23:59:59.000Z

130

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

131

Wind Levelized Cost of Energy: A Comparison of Technical and Financing Input Variables  

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

1 1 October 2009 Wind Levelized Cost of Energy: A Comparison of Technical and Financing Input Variables Karlynn Cory and Paul Schwabe National Renewable Energy Laboratory 1617 Cole Boulevard, Golden, Colorado 80401-3393 303-275-3000 * www.nrel.gov NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Operated by the Alliance for Sustainable Energy, LLC Contract No. DE-AC36-08-GO28308 Technical Report NREL/TP-6A2-46671 October 2009 Wind Levelized Cost of Energy: A Comparison of Technical and Financing Input Variables Karlynn Cory and Paul Schwabe Prepared under Task No. WER9.3550 NOTICE This report was prepared as an account of work sponsored by an agency of the United States government.

132

Variable Structure Control of a Doubly Fed Induction Generator for Wind Energy Conversion Systems  

Science Journals Connector (OSTI)

Abstract This paper presents the powers control of a variable speed wind turbine (WT) device based on a doubly fed induction generator (DFIG). Indeed, to increase the efficiency of the WT system, a robust variable structure control has been applied. DFIG has been previously presented in several works with diverse control diagrams using generally conventional PI controllers. Nevertheless, this type of controllers does not sufficiently handle some of WT resource characteristics such as wind fluctuations effects. Indeed, these can reduce WT performances. Furthermore, DFIG parameter variations should be accounted for. In this context, this paper proposes a high-order sliding mode to control the WT DFIG. Simulation results show that the proposed approach presents attractive features such as chattering-free behavior, good response to speed variations and robustness against machine parameter variations compared to the conventional first order sliding mode technique and even fuzzy sliding mode one.

E. Bounadja; A. Djahbar; Z. Boudjema

2014-01-01T23:59:59.000Z

133

The Minimum Wind Speed for Sustainable Turbulence in the Nocturnal Boundary Layer  

Science Journals Connector (OSTI)

The collapse of turbulence in the nocturnal boundary layer is studied by means of a simple bulk model that describes the basic physical interactions in the surface energy balance. It is shown that for a given mechanical forcing, the amount of ...

B. J. H. Van de Wiel; A. F. Moene; H. J. J. Jonker; P. Baas; S. Basu; J. M. M. Donda; J. Sun; A. A. M. Holtslag

2012-11-01T23:59:59.000Z

134

Universal power spectra for acoustic turbulence: Applications to wind waves, 1/f noise, and classical second sound  

Science Journals Connector (OSTI)

A continuum pumped full of waveenergy at an amplitude sufficiently large so that reversible nonlinearities dominate irreversible linear response becomes waveturbulent. In the limit of high nonlinearity acoustic turbulence and wind waveturbulence accumulate at 1/f and 1/f 5 power spectra respectively. A waveturbulent system can support new propagating energy modes analogous to second sound in superfluid He4. This hyperbolic (nondiffusive) transport could account for the anomalous diffusivity observed in plasma devices and for the difficulties faced in achieving confinement. The key to the understanding of these phenomena is the nonlinearity in the continuum mechanics which leads to three basic effects: (1) scattering of sound by sound to produce waves with sum and difference frequencies; (2) refraction of waves by a slowly varying (inhomogeneous) background; (3) reaction of the background due to changes in the distribution of sound waves. Details of these processes are presented in the framework of the Euler equations.

Seth Putterman; A. Larraza; P. H. Roberts

1986-01-01T23:59:59.000Z

135

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

Science Journals Connector (OSTI)

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

Cheryl Klipp

2007-12-01T23:59:59.000Z

136

Variable susceptance excitation control for dynamic performance improvement of a stand-alone wind turbine induction generator system  

Science Journals Connector (OSTI)

Isolated wind farms employ simple squirrel cage induction generators driven by variable speed wind turbines. Lacking control capability, such generation can contribute very little to network support. Wind turbines mostly do not take part in voltage and frequency control and if a disturbance occurs, the turbines may be disconnected and reconnected when normal operation has been resumed. From operation viewpoint, this is definitely not acceptable. A primary reason for the rigidity of operation is the lack of excitation adaptation under variable wind conditions. This article proposes incorporation of a variable capacitance controller at the generator terminal which will automatically adjust the needed excitation. Further improvement of transient profile of the stand-alone wind turbine generator has been proposed through inclusion of additional stabilising control. Simulation studies show that the proposed excitation controller with additional PID circuit provides very good transient profile following reasonable input torque variations.

A.H.M.A. Rahim; M. Ahsanul Alam

2009-01-01T23:59:59.000Z

137

Perpendicular Ion Heating by Low-Frequency Alfven-Wave Turbulence in the Solar Wind  

E-Print Network [OSTI]

We consider ion heating by turbulent Alfven waves (AWs) and kinetic Alfven waves (KAWs) with perpendicular wavelengths comparable to the ion gyroradius and frequencies smaller than the ion cyclotron frequency. When the turbulence amplitude exceeds a certain threshold, an ion's orbit becomes chaotic. The ion then interacts stochastically with the time-varying electrostatic potential, and the ion's energy undergoes a random walk. Using phenomenological arguments, we derive an analytic expression for the rates at which different ion species are heated, which we test by simulating test particles interacting with a spectrum of randomly phased AWs and KAWs. We find that the stochastic heating rate depends sensitively on the quantity epsilon = dv/vperp, where vperp is the component of the ion velocity perpendicular to the background magnetic field B0, and dv (dB) is the rms amplitude of the velocity (magnetic-field) fluctuations at the gyroradius scale. In the case of thermal protons, when epsilon eps1, the proton ...

Chandran, Benjamin D G; Rogers, Barrett N; Quataert, Eliot; Germaschewski, Kai

2010-01-01T23:59:59.000Z

138

The Role of Alpha Particles in the Evolution of the Solar-wind Turbulence toward Short Spatial Scales  

Science Journals Connector (OSTI)

We present a numerical study of the kinetic dynamics of protons and alpha particles during the evolution of the solar-wind turbulent cascade, in which the energy injected in large-scale slab-type Alfvénic fluctuations is transferred toward short spatial scale lengths, across the proton skin depth. We make use of a hybrid Vlasov-Maxwell code that integrates numerically the Vlasov equation for both the ion species, while the electrons are considered as a fluid. The system evolution is investigated in terms of different values of the electron to proton and alpha particle to proton temperature ratios. The numerical results show that the previously studied kinetic dynamics of protons is not strongly affected by the presence of alpha particles, at least when they are present in low concentration. Our simulations not only provide a physical explanation for the generation of beams of accelerated particles along the direction of the ambient magnetic field for both protons and alpha particles, but also show that this mechanism is more efficient for protons than for alpha particles, in agreement with recent solar-wind data analyses.

D. Perrone; F. Valentini; P. Veltri

2011-01-01T23:59:59.000Z

139

Fast Solar Wind and Geomagnetic Variability during the Descendant Phase of the 11?yr Solar Cycle  

Science Journals Connector (OSTI)

Solar activity and its consequences for the interplanetary space are governing and perturbing the Earth’s magnetosphere. The response of the terrestrial magnetosphere displayed as geomagnetic disturbances is measured by several geomagnetic indices. This paper analyses the geomagnetic variability during the descendant phases of the last four solar cycles (Nos. 20–23) under the influence of the high speed streams of the solar wind. The descendant phases of the 11?yr solar cycle are complex intervals of the irrespective cycles during which two magnetic dipoles with opposite polarities are present on the Sun. The variability and statistics of the stream intensity and geomagnetic index Ap during the descendant phases revealed strong activity. The correlation between the geomagnetic indices and the stream intensity during the analyzed intervals was examined. The energy transfer from solar wind into the terrestrial magnetosphere during the main phase of some geomagnetic storm depends of the solar wind energy and magnetic fields (terrestrial and heliospheric) configuration which allows or not reconnections of these fields. Analysis of some geomagnetic storms during the descendant branch of solar cycle 23 put into evidence the main role of the B z component of heliospheric magnetic field in this transfer.

G. Maris; O. Maris

2011-01-01T23:59:59.000Z

140

Simplified turbulent spiral boundary layer and thermal wind simulator for acid rain modeling  

SciTech Connect (OSTI)

To determine the possible future impact of acid rain on the ecosystem requires the ability to numerically simulate the transport of various acids and their precursors from various sources to the locations of interest. Such a simulation is very complex and includes the evolution of the materials of interest as an aerosol within the ever changing local atmospheric motion. Wind patterns, however, are complex and difficult to model. They depend not only on local surface conditions and topology but on the global meteorological conditions. This paper presents an algebraic model to be used to simulate the vertical variation of the wind velocity and direction. The proposed model requires a minimum of input yet it qualitatively captures the mechanistic behavior of the wind with altitude. Results of the model are compared with both finite difference calculations and field data.

Lemmon, E.C.; Wiersma, G.B.; Bruns, D.A.

1986-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "turbulence wind variability" 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

Tidal Flow Turbulence Measurements  

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

max quire specification of a turbulence intensity, and it is a metric in the wind energy industry. For acoustic Dop surements, a noise-corrected expression of...

142

Effects of meteorological variables on exergetic efficiency of wind turbine power plants  

Science Journals Connector (OSTI)

This present paper deals with exergy efficiency results of the Wind Turbine Power Plants (WTPPs). Effects of meteorological variables such as air density, pressure difference between state points, humidity, and ambient temperature on exergy efficiency are discussed in a satisfactory way. Some key parameters are given monthly for the three turbines. Exergy efficiency differs from 0.23 to 0.27 while temperature is changing from 268.15 K to 308.15 K with air density 1.368–1.146 (kg/m3). While pressure difference (?P) between inlet and outlet of the turbine differs from 100 to 1100 (Pa), exergy efficiency decreases fairly for different wind speeds. While specific humidity is changing from 0.001 to 0.015 (kgwater/kgdry air), exergy efficiency decreases gently. Generally these meteorological variables are neglected while planning WTPPs, but this neglect can cause important errors in calculations and energy plans. Obtained results indicate that while planning \\{WTPPs\\} meteorological variables must be taken into account.

Omer Baskut; Onder Ozgener; Leyla Ozgener

2010-01-01T23:59:59.000Z

143

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

144

A study of wind variability in the lower troposphere through power spectrum analysis at mesoscale frequencies  

E-Print Network [OSTI]

on the theoretical and practical application of the analysis method comes directly from this reference. B. Fundamental Assum tions of Power S ectrum Theor Consider a function of time X(t), such as wind speed, which is generated by a random process. Then the value... of the function X(t) at any particular point in time is a random variable. This random process may or may not have a Gaussian or normal distribution but it is a fundamental assumption (at least in the development of the theory) that the random process...

Cornett, John Sheldon

1966-01-01T23:59:59.000Z

145

VELOCITY-SHEAR-INDUCED MODE COUPLING IN THE SOLAR ATMOSPHERE AND SOLAR WIND: IMPLICATIONS FOR PLASMA HEATING AND MHD TURBULENCE  

SciTech Connect (OSTI)

We analytically consider how velocity shear in the corona and solar wind can cause an initial Alfven wave to drive up other propagating signals. The process is similar to the familiar coupling into other modes induced by non-WKB refraction in an inhomogeneous plasma, except here the refraction is a consequence of velocity shear. We limit our discussion to a low-beta plasma, and ignore couplings into signals resembling the slow mode. If the initial Alfven wave is propagating nearly parallel to the background magnetic field, then the induced signals are mainly a forward-going (i.e., propagating in the same sense as the original Alfven wave) fast mode, and a driven signal propagating like a forward-going Alfven wave but polarized like the fast mode; both signals are compressive and subject to damping by the Landau resonance. For an initial Alfven wave propagating obliquely with respect to the magnetic field, the induced signals are mainly forward- and backward-going fast modes, and a driven signal propagating like a forward-going Alfven wave but polarized like the fast mode; these signals are all compressive and subject to damping by the Landau resonance. A backward-going Alfven wave, thought to be important in the development of MHD turbulence, is also produced, but it is very weak. However, we suggest that for oblique propagation of the initial Alfven wave the induced fast-polarized signal propagating like a forward-going Alfven wave may interact coherently with the initial Alfven wave and distort it at a strong-turbulence-like rate.

Hollweg, Joseph V.; Chandran, Benjamin D. G. [Space Science Center, Morse Hall, University of New Hampshire, Durham, NH 03824 (United States); Kaghashvili, Edisher Kh., E-mail: joe.hollweg@unh.edu, E-mail: ekaghash@aer.com, E-mail: benjamin.chandran@unh.edu [Atmospheric and Environmental Research, A Verisk Analytics Company, 131 Hartwell Avenue, Lexington, MA 02421 (United States)

2013-06-01T23:59:59.000Z

146

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

147

PROTON, ELECTRON, AND ION HEATING IN THE FAST SOLAR WIND FROM NONLINEAR COUPLING BETWEEN ALFVENIC AND FAST-MODE TURBULENCE  

SciTech Connect (OSTI)

In the parts of the solar corona and solar wind that experience the fewest Coulomb collisions, the component proton, electron, and heavy ion populations are not in thermal equilibrium with one another. Observed differences in temperatures, outflow speeds, and velocity distribution anisotropies are useful constraints on proposed explanations for how the plasma is heated and accelerated. This paper presents new predictions of the rates of collisionless heating for each particle species, in which the energy input is assumed to come from magnetohydrodynamic (MHD) turbulence. We first created an empirical description of the radial evolution of Alfven, fast-mode, and slow-mode MHD waves. This model provides the total wave power in each mode as a function of distance along an expanding flux tube in the high-speed solar wind. Next, we solved a set of cascade advection-diffusion equations that give the time-steady wavenumber spectra at each distance. An approximate term for nonlinear coupling between the Alfven and fast-mode fluctuations is included. For reasonable choices of the parameters, our model contains enough energy transfer from the fast mode to the Alfven mode to excite the high-frequency ion cyclotron resonance. This resonance is efficient at heating protons and other ions in the direction perpendicular to the background magnetic field, and our model predicts heating rates for these species that agree well with both spectroscopic and in situ measurements. Nonetheless, the high-frequency waves comprise only a small part of the total Alfvenic fluctuation spectrum, which remains highly two dimensional as is observed in interplanetary space.

Cranmer, Steven R.; Van Ballegooijen, Adriaan A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2012-08-01T23:59:59.000Z

148

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

149

TURBULENT PRESSURE IN THE ENVELOPES OF YELLOW HYPERGIANTS AND LUMINOUS BLUE VARIABLES  

E-Print Network [OSTI]

turbulent pressure) affects the structure and stability of luminous post­red-supergiant stars is critically zone lies too deep below the surface to influence the formal dynamical stability or instability more than a huge bubble of blackbody radiation. Since radiation pressure tends to decrease stellar

150

Great Plains Turbulence Environment: Its Origins, Impact, and Simulation  

SciTech Connect (OSTI)

This paper summarizes the known impacts of nocturnal turbulence on wind turbine performance and operations.

Kelley, N. D.; Jonkman, B. J.; Scott, G. N.

2006-12-01T23:59:59.000Z

151

Empirical Analysis of the Variability of Wind Generation in India: Implications for Grid Integration  

E-Print Network [OSTI]

wind generation and load data from two states in India,wind generation and load data from two states in India viz.actual wind generation and load data from the Indian states

Phadke, Amol

2014-01-01T23:59:59.000Z

152

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

153

Near-Infrared, Kilosecond Variability of the Wisps And Jet in the Crab Pulsar Wind Nebula  

SciTech Connect (OSTI)

We present a time-lapse sequence of 20 near-infrared (J- and K'-band) snapshots of the central 20'' x 20'' of the Crab pulsar wind nebula, taken at sub-arcsecond resolution with the Hokupa'a/QUIRC adaptive optics camera on the Gemini North Telescope, and sampled at intervals of 10 minutes and 24 hours. It is observed that the equatorial wisps and polar knots in the termination shock of the pulsar wind appear to fluctuate in brightness on kilosecond time-scales. Maximum flux variations of {+-}24 {+-} 4 and {+-}14 {+-} 4 per cent relative to the mean (in 1.2 ks) are measured for the wisps and knots respectively, with greatest statistical significance in J band where the nebula background is less prominent. The J and K' flux densities imply different near-infrared spectra for the nonthermal continuum emission from the wisps and outermost polar knot (''sprite''), giving F{sub {nu}} {proportional_to} {nu}{sup -0.56{+-}0.12} and F{sub {nu}} {proportional_to} {nu}{sup -0.21{+-}0.13} respectively. The data are compared with existing optical and UV photometry and applied to constrain theories of the variability of the wisps (relativistic ion-cyclotron instability) and knots (relativistic fire hose instability).

Melatos, Andrew; Scheltus, D.; /Melbourne U.; Whiting, M.T.; /New South Wales U.; Eikenberry, S.S.; /Florida U.; Romani, R.W.; /Stanford U., Phys. Dept.; Rigaut, F.; /Gemini; Spitkovsky, A.; /KIPAC, Menlo Park; Arons, J.; /UC, Berkeley, Astron. Dept.; Payne, D.J.B.; /Melbourne U.

2006-01-11T23:59:59.000Z

154

Deep-Sea Research II 53 (2006) 3141 Decadal variability of wind-energy input to the world ocean  

E-Print Network [OSTI]

- tion is emerging. Although the ocean receives a huge amount of thermal energy, it cannot convert such thermal energy into mechanical energy very effi- ciently because the ocean is heated and cooled fromDeep-Sea Research II 53 (2006) 31­41 Decadal variability of wind-energy input to the world ocean

Huang, Rui Xin

155

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

156

A nuclear wind/solar oil-shale system for variable electricity and liquid fuels production  

SciTech Connect (OSTI)

The recoverable reserves of oil shale in the United States exceed the total quantity of oil produced to date worldwide. Oil shale contains no oil, rather it contains kerogen which when heated decomposes into oil, gases, and a carbon char. The energy required to heat the kerogen-containing rock to produce the oil is about a quarter of the energy value of the recovered products. If fossil fuels are burned to supply this energy, the greenhouse gas releases are large relative to producing gasoline and diesel from crude oil. The oil shale can be heated underground with steam from nuclear reactors leaving the carbon char underground - a form of carbon sequestration. Because the thermal conductivity of the oil shale is low, the heating process takes months to years. This process characteristic in a system where the reactor dominates the capital costs creates the option to operate the nuclear reactor at base load while providing variable electricity to meet peak electricity demand and heat for the shale oil at times of low electricity demand. This, in turn, may enable the large scale use of renewables such as wind and solar for electricity production because the base-load nuclear plants can provide lower-cost variable backup electricity. Nuclear shale oil may reduce the greenhouse gas releases from using gasoline and diesel in half relative to gasoline and diesel produced from conventional oil. The variable electricity replaces electricity that would have been produced by fossil plants. The carbon credits from replacing fossil fuels for variable electricity production, if assigned to shale oil production, results in a carbon footprint from burning gasoline or diesel from shale oil that may half that of conventional crude oil. The U.S. imports about 10 million barrels of oil per day at a cost of a billion dollars per day. It would require about 200 GW of high-temperature nuclear heat to recover this quantity of shale oil - about two-thirds the thermal output of existing nuclear reactors in the United States. With the added variable electricity production to enable renewables, additional nuclear capacity would be required. (authors)

Forsberg, C. [Massachusetts Inst. of Technology, 77 Massachusetts Ave., Cambridge, MA 012139 (United States)

2012-07-01T23:59:59.000Z

157

Multidecadal variability of the overturning circulation in presence of eddy turbulence.  

Science Journals Connector (OSTI)

At low resolution, idealized ocean circulation models forced by prescribed differential surface heat fluxes show spontaneous multidecadal variability depending critically on eddy diffusivity coefficients. The existence of this critical threshold ...

Thierry Huck; Olivier Arzel; Florian Sévellec

158

Optimizing the Design of a Hybrid Solar-Wind Power Plant to meet Variable Power Demand  

Science Journals Connector (OSTI)

Not enough studies have been done on operating the two most available and renewable energy sources, sun and wind energy, alongside one another. A complementary ... presents an optimal design for a hybrid solar-wind

K. Mousa; A. Diabat

2011-01-01T23:59:59.000Z

159

Observations of turbulent fluxes and turbulence dynamics in the ocean surface boundary layer  

E-Print Network [OSTI]

This study presents observations of turbulence dynamics made during the low winds portion of the Coupled Boundary Layers and Air-Sea Transfer experiment (CBLAST-Low). Observations were made of turbulent fluxes, turbulent ...

Gerbi, Gregory Peter

2008-01-01T23:59:59.000Z

160

Revealing the Impact of Climate Variability on the Wind Resource Using Data Mining Techniques (Poster)  

SciTech Connect (OSTI)

A data mining technique called 'k-means clustering' can be used to group winds at the NWTC into 4 major clusters. The frequency of some winds in the clusters is correlated with regional pressure gradients and climate indices. The technique could also be applied to wind resource assessment and selecting scenarios for flow modeling.

Clifton, A.; Lundquist, J.

2011-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "turbulence wind variability" 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

Exoplanet transit variability: bow shocks and winds around HD 189733b  

Science Journals Connector (OSTI)

......both cases, the maps show the distribution...2.2 Stellar wind model The magnetic surface maps are used as one...conditions in our stellar wind simulation. We...equations, for the wind mass density rhow, gas pressure p w, the velocity of the plasma and......

J. Llama; A. A. Vidotto; M. Jardine; K. Wood; R. Fares; T. I. Gombosi

2013-01-01T23:59:59.000Z

162

Fluctuating wind power penetration as limited by frequency standard.  

E-Print Network [OSTI]

??Fluctuating wind power is due to wind turbulence and is the part which should be filtered out leaving behind the more predictable mean wind power… (more)

Luo, Changling, 1980-

2005-01-01T23:59:59.000Z

163

The Sun and the solar wind variability of different time-scales and the climate dynamics  

Science Journals Connector (OSTI)

The role and place of the solar wind energy in the whole spectra of the solar emissions, which could influence Earth's climate dynamics are investigated. Reliable indicators of the direct coupling between the solar wind disturbances and the temperature short-term variations in the high-latitude stratosphere are presented. In the long-terms (several solar cycles), variations of the solar wind dynamic pressure are similar to the correspondent total solar irradiance (TSI) temporal changes.

L.N Makarova; A.V Shirochkov

2004-01-01T23:59:59.000Z

164

On the role of wind driven ocean dynamics in tropical Atlantic variability  

E-Print Network [OSTI]

The response of the tropical Atlantic Ocean to wind stress forcing on seasonal and interannual time scales is examined using an ocean data assimilation product from the Geophysical Fluid Dynamics Laboratory (GFDL), and an ocean general circulation...

Da Silva, Meyre Pereira

2006-08-16T23:59:59.000Z

165

Geographical and seasonal variability of the global "practical" wind Cristina L. Archer a,*, Mark Z. Jacobson b  

E-Print Network [OSTI]

(GATOR-GCMOM) that dynamically calculates the instantaneous wind power of a modern 5 MW wind turbine

166

Effects of Atmospheric Turbulence on Ballistic Testing  

Science Journals Connector (OSTI)

The effects of atmospheric turbulence on munition target scatter are determined from numerical simulations of ballistic trajectories through many realizations of realistic simulated turbulent wind fields. A technique is evaluated for correcting ...

Rod Frehlich; Robert Sharman; Charles Clough; Michael Padovani; Kelly Fling; Ward Boughers; W. Scott Walton

2008-05-01T23:59:59.000Z

167

turbulence | OpenEI  

Open Energy Info (EERE)

turbulence turbulence Dataset Summary Description This raw data reflects readings from instruments mounted on or near a 82 meter meteorological tower located at the National Wind Technology Center (NWTC), approximately 5 miles south of Boulder, CO (specifically: 39.9107 N, 105.2348 W, datum WGS84). Source NREL Date Released Unknown Date Updated Unknown Keywords DOE irradiance NREL NWTC temperature turbulence wind wind direction wind speed Data text/plain icon Raw data (txt, 82 KiB) application/vnd.openxmlformats-officedocument.spreadsheetml.sheet icon Raw data field descriptions (xlsx, 52.5 KiB) Quality Metrics Level of Review Some Review Comment Data have not been reviewed for accuracy or completeness; disclaimer available (http://www.nrel.gov/disclaimer.html). Temporal and Spatial Coverage

168

Costs of Solar and Wind Power Variability for Reducing CO2 Emissions  

Science Journals Connector (OSTI)

Our research differs from earlier solar PV studies because we use real power output data from operational utility-scale plants to calculate the variability and cost of variability. ... In addition, the ISO utilizes up and down regulation equivalent to the minimum and maximum deviation from qh, respectively (lower right graph). ... (9) The Docket states that ISOs may use the same rate they charge utilities for load variability in Schedule 3. FERC envisions that individual transmission utilities can apply to charge different rates as long as they “demonstrate that the per-unit cost of regulation reserve capacity is somehow different when such capacity is utilized to address system variability associated with generator resources”. ...

Colleen Lueken; Gilbert E. Cohen; Jay Apt

2012-08-09T23:59:59.000Z

169

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

170

Free and forced tropical variability: role of the wind-evaporation-sea surface temperature (WES) feedback  

E-Print Network [OSTI]

. : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 11 3 Spatial distribution of the ocean mixed layer depth used in the Slab Ocean Model. : : : : : : : : : : : : : : : : : : : : : : : : : : : : 22 4 Annual mean (a) SST (contour interval: 2 K) and (b) latent heat ux (contour interval: 40 W/m2...) as simulated in CCM3-SOM. : : : : 27 5 Annual mean (a) surface winds and (b) convective precipitation (contour interval: 2 mm/day) as simulated in CCM3-SOM. : : : : : : 28 6 Di erence in annual mean (a) SST (contour interval: 0.2 K): WES-o -SOM - CCM3-SOM...

Mahajan, Salil

2009-05-15T23:59:59.000Z

171

Use of Solar and Wind as a Physical Hedge against Price Variability within a Generation Portfolio  

SciTech Connect (OSTI)

This study provides a framework to explore the potential use and incremental value of small- to large-scale penetration of solar and wind technologies as a physical hedge against the risk and uncertainty of electricity cost on multi-year to multi-decade timescales. Earlier studies characterizing the impacts of adding renewable energy (RE) to portfolios of electricity generators often used a levelized cost of energy or simplified net cash flow approach. In this study, we expand on previous work by demonstrating the use of an 8760 hourly production cost model (PLEXOS) to analyze the incremental impact of solar and wind penetration under a wide range of penetration scenarios for a region in the Western U.S. We do not attempt to 'optimize' the portfolio in any of these cases. Rather we consider different RE penetration scenarios, that might for example result from the implementation of a Renewable Portfolio Standard (RPS) to explore the dynamics, risk mitigation characteristics and incremental value that RE might add to the system. We also compare the use of RE to alternative mechanisms, such as the use of financial or physical supply contracts to mitigate risk and uncertainty, including consideration of their effectiveness and availability over a variety of timeframes.

Jenkin, T.; Diakov, V.; Drury, E.; Bush, B.; Denholm, P.; Milford, J.; Arent, D.; Margolis, R.; Byrne, R.

2013-08-01T23:59:59.000Z

172

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

173

Saturation wind power potential and its implications for wind energy  

Science Journals Connector (OSTI)

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

Mark Z. Jacobson; Cristina L. Archer

2012-01-01T23:59:59.000Z

174

Perpendicular ion acceleration in whistler turbulence  

SciTech Connect (OSTI)

Whistler turbulence is an important contributor to solar wind turbulence dissipation. This turbulence contains obliquely propagating whistler waves at electron scales, and these waves have electrostatic components perpendicular to the mean magnetic field. In this paper, a full kinetic, two-dimensional particle-in-cell simulation shows that whistler turbulence can accelerate ions in the direction perpendicular to the mean magnetic field. When the ions pass through wave-particle resonances region in the phase space during their cyclotron motion, the ions are effectively accelerated in the perpendicular direction. The simulation results suggest that whistler turbulence contributes to the perpendicular heating of ions observed in the solar wind.

Saito, S. [Graduate School of Science, Nagoya University, Furocho, Chikusa, Nagoya 464-8601 (Japan)] [Graduate School of Science, Nagoya University, Furocho, Chikusa, Nagoya 464-8601 (Japan); Nariyuki, Y. [Faculty of Human Development, University of Toyama, 3190, Toyama 930-8555 (Japan)] [Faculty of Human Development, University of Toyama, 3190, Toyama 930-8555 (Japan)

2014-04-15T23:59:59.000Z

175

Effects of variable renewable power on a country-scale electricity system: High penetration of hydro power plants and wind farms in electricity generation  

Science Journals Connector (OSTI)

The present article analyses the effects caused by variable power. The analysis concerns a country-scale electricity system with a relatively high penetration of seasonally variable hydro power plants and wind farms in the total electricity generation in 2030. For this purpose, the Latvian electricity system was chosen as an appropriate case study, as around half of its electricity is already generated from hydro power and numerous wind farm installations are planned for 2030. Results indicate that in such systems high renewable power variations occur between seasons causing a high probability of power deficit in the winter and power surplus in the spring. Based on the results, the wind farms' influence on the power deficit and surplus occurrences are discussed in detail. Wind farm generation decreases the probability of the electricity system being in power deficit, but increases the probability of the system being in power surplus. In the latter situation, the maximum value of power surplus increases since it is enhanced by the wind farm generation. Probability equations to express these changes are provided.

Arturs Purvins; Ioulia T. Papaioannou; Irina Oleinikova; Evangelos Tzimas

2012-01-01T23:59:59.000Z

176

The Impact of Variable Market Price on Optimal Control of Wind-Hydro Storage System in Kenya  

Science Journals Connector (OSTI)

The Lake Turkana Wind Power Project (LTWP) in Northern Kenya is currently under development, scheduled to bring 300MW of wind generation online by the end of 2016. The economic issues raised by the structure of the Kenyan electricity market include a ... Keywords: Wind Power, Developing Countries, Electricity Pricing

Maureen Murage; Judith B. Cardell; June Lukuyu; C. Lindsay Anderson

2014-01-01T23:59:59.000Z

177

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

178

NREL Studies Wind Farm Aerodynamics to Improve Siting (Fact Sheet...  

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

atmosphere contains large-scale turbulence struc- tures that propagate through the wind turbines and wind farms and influence wake motion. Over the course of a day, the wind...

179

Plug-in hybrid electric vehicles as a way to maximize the integration of variable renewable energy in power systems: The case of wind generation in northeastern Brazil  

Science Journals Connector (OSTI)

Several studies have proposed different tools for analyzing the integration of variable renewable energy into power grids. This study applies an optimization tool to model the expansion of the electric power system in northeastern Brazil, enabling the most efficient dispatch of the variable output of the wind farms that will be built in the region over the next 20 years. The expected combined expansion of wind generation with conventional inflexible generation facilities, such as nuclear plants and run-of-the-river hydropower plants, poses risks of future mismatch between supply and demand in northeastern Brazil. Therefore, this article evaluates the possibility of using a fleet of plug-in hybrid electric vehicles (PHEVs) to regularize possible energy imbalances. Findings indicate that a dedicated fleet of 500 thousand \\{PHEVs\\} in 2015, and a further 1.5 million in 2030, could be recharged overnight to take advantage of the surplus power generated by wind farms. To avoid the initial costs of smart grids, this article suggests, as a first step, the use of a governmental PHEV fleet that allows fleet managers to control battery charging times. Finally, the study demonstrates the advantages of optimizing simultaneously the power and transport sectors to test the strategy suggested here.

Bruno Soares M.C. Borba; Alexandre Szklo; Roberto Schaeffer

2012-01-01T23:59:59.000Z

180

V444 Cyg X-ray and polarimetric variability: Radiative and Coriolis forces shape the wind collision region  

E-Print Network [OSTI]

We present results from a study of the eclipsing, colliding-wind binary V444 Cyg that uses a combination of X-ray and optical spectropolarimetric methods to describe the 3-D nature of the shock and wind structure within the system. We have created the most complete X-ray light curve of V444 Cyg to date using 40 ksec of new data from Swift, and 200 ksec of new and archived XMM-Newton observations. In addition, we have characterized the intrinsic, polarimetric phase-dependent behavior of the strongest optical emission lines using data obtained with the University of Wisconsin's Half-Wave Spectropolarimeter. We have detected evidence of the Coriolis distortion of the wind-wind collision in the X-ray regime, which manifests itself through asymmetric behavior around the eclipses in the system's X-ray light curves. The large opening angle of the X-ray emitting region, as well as its location (i.e. the WN wind does not collide with the O star, but rather its wind) are evidence of radiative braking/inhibition occurri...

Lomax, Jamie R; Hoffman, Jennifer L; Russell, Christopher M P; De Becker, Michael; Corcoran, Michael F; Davidson, James W; Neilson, Hilding R; Owocki, Stan; Pittard, Julian M; Pollock, Andy M T

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "turbulence wind variability" 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

Seasonal variability in coastal fronts and its influence on sea surface wind in the Northern South China Sea  

Science Journals Connector (OSTI)

Abstract High-resolution reanalysis data of Sea Surface Temperature (SST) show pronounced seasonal variations in oceanic fronts in the coastal area of the Northern South China Sea (NSCS), which are accompanied by the seasonality of monsoons. The NSCS oceanic fronts cover a wider area of the coastal sea in winter than in summer as strong winter monsoons progress. Nonetheless, the average SST gradients of the frontal area in both seasons are comparable. The response of surface wind to SST perturbations attributed to oceanic fronts in the NSCS coastal area has also been investigated by the observation data of satellite borne scatterometers and the simulation data of the Weather Research and Forecasting (WRF) model. Both the satellite observations and the simulations of the WRF model show apparent positive linear SST-wind coupling for most months in 2008, indicating the local influence of coastal SST fronts on the sea surface wind in the NSCS. The SST-wind coupling coefficients in the NSCS coastal sea are larger than those observed at mid-latitude oceans but smaller than those observed near equatorial oceans. It is also found that the influence of topography on the sea surface wind could be more important than that of the SST front at the southern end of the Taiwan Strait in winter. The transition of the monsoon could also affect the SST-wind coupling in the NSCS.

Rui Shi; Xinyu Guo; Dongxiao Wang; LiLi Zeng; Ju Chen

2013-01-01T23:59:59.000Z

182

Low-altitude atmospheric turbulence around an airport  

E-Print Network [OSTI]

speed and the average wind speed computed over an entire run (approximately 1 hr). iv Profiles of wind speed were approximately logarithmic, but profiles of turbulent energy showed a large increase in the wake of large obstructions. Spectra of wind... from u 30-sec averages 56 57 28 Spectra of accelerometer and wind data for same period 59 LIST OF SYMBOLS Symbol Definition Exchange coefficient for momentum Height Time Kinetic energy Average kinetic energy of turbulence u' + v'2 + w' (' 2...

Cass, Stanley Dale

2012-06-07T23:59:59.000Z

183

NREL: Learning - Wind Energy Basics: How Wind Turbines Work  

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

Wind Energy Basics: How Wind Turbines Work Wind Energy Basics: How Wind Turbines Work We have been harnessing the wind's energy for hundreds of years. From old Holland to farms in the United States, windmills have been used for pumping water or grinding grain. Today, the windmill's modern equivalent-a wind turbine-can use the wind's energy to generate electricity. Wind turbines, like windmills, are mounted on a tower to capture the most energy. At 100 feet (30 meters) or more aboveground, they can take advantage of the faster and less turbulent wind. Turbines catch the wind's energy with their propeller-like blades. Usually, two or three blades are mounted on a shaft to form a rotor. A blade acts much like an airplane wing. When the wind blows, a pocket of low-pressure air forms on the downwind side of the blade. The low-pressure

184

Kepler photometry and optical spectroscopy of the ZZ Lep central star of the Planetary Nebula NGC 6826: rotational and wind variability  

E-Print Network [OSTI]

We present three years of long-cadence and over one year of short-cadence photometry of the central star of the Planetary Nebula NGC 6826 obtained with the Kepler spacecraft, and temporally coinciding optical spectroscopy. The light curves are dominated by incoherent variability on time scales of several hours, but contain a lower-amplitude periodicity of 1.23799 d. The temporal amplitude and shape changes of this signal are best explicable with a rotational modulation, and are not consistent with a binary interpretation. We argue that we do not observe stellar pulsations within the limitations of our data, and show that a binary central star with an orbital period less than seven days could only have escaped our detection in the case of low orbital inclination. Combining the photometric and spectroscopic evidence, we reason that the hourly variations are due to a variable stellar wind, and are global in nature. The physical cause of the wind variability of NGC 6826 and other ZZ Leporis stars is likely relate...

Handler, G; Urbaneja, M A; Antoci, V; Twicken, J D; Barclay, T

2013-01-01T23:59:59.000Z

185

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

186

Turbulence in Astrophysical and Laboratory Plasmas  

E-Print Network [OSTI]

MIPSE, Univ of Michigan September 15, 2010 #12;Contributing Colleagues Steve Cowley (UKAEA & Imperial-principles modeling · Identification of Alfvenic solar wind turbulence · Conclusion #12;Kinetic theory when (or ) f

Shyy, Wei

187

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

188

Two techniques for forecasting clear air turbulence  

E-Print Network [OSTI]

for the height of the 200- and )00-mb pressure surfaces associated with nonturbulent and turbulent cases . . . . . . o. . . . . o o ~ o ~ . ~ . 17 4. Empirical frequency distributions for the temperature of the 200- and 300-mb pressure surfaces associated... with nonturbulent and turbulent areas. . . . . . ~ . . . . . ~ . ~ ~ Empirical frequency distributions of the zonal wind component on the 200- and 300-mb press- ure surfaces associated with nonturbulent and turbulent areas . . . . . . . . . . . . ~ ~ 20...

Arbeiter, Randolph George

2012-06-07T23:59:59.000Z

189

Managing Wind Power Forecast Uncertainty in Electric Grids.  

E-Print Network [OSTI]

??Electricity generated from wind power is both variable and uncertain. Wind forecasts provide valuable information for wind farm management, but they are not perfect. Chapter… (more)

Mauch, Brandon Keith

2012-01-01T23:59:59.000Z

190

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

191

Wind Energy Assessment Study for Nevada -- Tall Tower Deployment (Stone Cabin): 26 June 2005 - 31 December 2007  

SciTech Connect (OSTI)

The objective of this work effort was to characterize wind shear and turbulence for representative wind-developable areas in Nevada.

Koracin, D.; Reinhardt, R.; McCurdy, G.; Liddle, M.; McCord, T.; Vellore, R.; Minor, T.; Lyles, B.; Miller, D.; Ronchetti, L.

2009-12-01T23:59:59.000Z

192

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

193

Distinct Modes of Internal Variability in the Global Meridional Overturning Circulation Associated with the Southern Hemisphere Westerly Winds  

Science Journals Connector (OSTI)

The internal variability of the global meridional overturning circulation (GMOC) in long-term integration of the earth system model Community Earth System Models (COSMOS) is examined in this study. Two distinct modes of the GMOC, which are closely ...

Wei Wei; Gerrit Lohmann; Mihai Dima

2012-05-01T23:59:59.000Z

194

CHAPTER ____ THE AIR-WATER INTERFACE: TURBULENCE  

E-Print Network [OSTI]

.g. from paper mills. The desorption of dissolved substances, like PCBs, from inland and coastal water at an unsheared air-water interface, i.e., a situation in which the winds are light and the fluid motions category, we consider situations with significant wind shear at the surface. In this case, the turbulence

California at Santa Barbara, University of

195

NREL Software Models Performance of Wind Plants (Fact Sheet)...  

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

effects of weather patterns, turbulence, and complex terrain on the performance of wind turbines and plants. SOWFA simulates fluid dynam- ics on scales from regional weather to...

196

Velcro Measurement of Turbulence Kinetic Energy Dissipation Rate ?  

Science Journals Connector (OSTI)

Turbulence in the ocean results from many different processes operating over a wide range of space scales and timescales, with spatial and temporal variability particularly extreme in coastal oceans. If the origins and effects of turbulent ...

Ann E. Gargett

1999-12-01T23:59:59.000Z

197

Environmental impact of wind energy  

Science Journals Connector (OSTI)

One purpose of wind turbines is to provide pollution-free electric power at a reasonable price in an environmentally sound way. In this focus issue the latest research on the environmental impact of wind farms is presented. Offshore wind farms affect the marine fauna in both positive and negative ways. For example, some farms are safe havens for porpoises while other farms show fewer harbor porpoises even after ten years. Atmospheric computer experiments are carried out to investigate the possible impact and resource of future massive installations of wind turbines. The following questions are treated. What is the global capacity for energy production by the wind? Will the added turbulence and reduced wind speeds generated by massive wind farms cool or heat the surface? Can wind farms affect precipitation? It is also shown through life-cycle analysis how wind energy can reduce the atmospheric emission of eight air pollutants. Finally, noise generation and its impact on humans are studied.

J Mann; J Teilmann

2013-01-01T23:59:59.000Z

198

Effect of grid size on building wind according to a computation fluid dynamics simulation  

Science Journals Connector (OSTI)

Skyscrapers negatively impact the environment by creating gusty winds, known as building winds, which are the result of descending turbulences ... air by tall buildings. Usually, a building wind impact assessment...

Jae-Cheol Kim; Kyoo-Seock Lee

2011-02-01T23:59:59.000Z

199

Characterizing the Fluctuations of Wind Power Production by Multi-time Statistics  

Science Journals Connector (OSTI)

The fluctuations of electrical energy, generated by wind turbines, reflect the interaction between the turbulent wind field and a complex technical system. In ... article we study time series of the integrated wind

Oliver Kamps

2014-01-01T23:59:59.000Z

200

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 Nørkær Sørensen; Poul-Erik Morthorst

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "turbulence wind variability" 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

Plasma turbulence  

SciTech Connect (OSTI)

The origin of plasma turbulence from currents and spatial gradients in plasmas is described and shown to lead to the dominant transport mechanism in many plasma regimes. A wide variety of turbulent transport mechanism exists in plasmas. In this survey the authors summarize some of the universally observed plasma transport rates.

Horton, W. [Univ. of Texas, Austin, TX (United States). Inst. for Fusion Studies; Hu, G. [Globalstar LP, San Jose, CA (United States)

1998-07-01T23:59:59.000Z

202

October 11, 2011 Wind Generation  

E-Print Network [OSTI]

years. #12;Reading on ESRP 285 Website #12;The Competition: Gas-Fired Generation from a Combined CycleESRP 285 October 11, 2011 Wind Generation · Videos · Power Point Lecture #12;Wind Videos Wind (CC) Power Plant #12;Wind Investors Face These Costs #12;Fixed Costs #12;Variable Costs #12;Bottom

Ford, Andrew

203

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

204

Untangling the roles of wind, run-off and tides in Prince William Sound  

Science Journals Connector (OSTI)

Prince William Sound (PWS) oceanic circulation is driven by a combination of local wind, large run-off and strong tides. Using a regional oceanic model of the Gulf of Alaska, adequately resolving the mean circulation and mesoscale eddies, we configure a series of three nested domains. The inner domain zooms in on Prince William Sound with a 1-km horizontal grid resolution. We analyze a set of four experiments with different combinations of run-off, wind and tides to demonstrate the relative influence of these forcing on the central Sound mean circulation cell and its seasonal variability. The mean circulation in the central PWS region is generally characterized by a cyclonic cell. When forced only by the wind, the circulation is cyclonic in winter and fall and strongly anticyclonic in summer. The addition of freshwater run-off greatly enhances the eddy kinetic energy in PWS partly through near-surface baroclinic instabilities. This leads to a much more intermittent circulation in the central Sound, with the presence of intense small-scale turbulence and a disappearance of the summer wind-forced anticyclonic cell. The addition of tides reduces the turbulence intensity (relatively to the experiment with run-off only), particularly in the central Sound. The generation of turbulent motions by baroclinic processes is lowered by tidal mixing and by modification of the exchange at Hinchinbrook Entrance. Tides have an overall stabilizing effect on the central Sound circulation. Tidal rectification currents help maintain a mean cyclonic circulation throughout the year.

François Colas; Xiaochun Wang; Xavier Capet; Yi Chao; James C. McWilliams

2013-01-01T23:59:59.000Z

205

Surface Wind Regionalization in Complex Terrain  

Science Journals Connector (OSTI)

Daily wind variability in the Comunidad Foral de Navarra in northern Spain was studied using wind observations at 35 locations to derive subregions with homogeneous temporal variability. Two different methodologies based on principal component ...

P. A. Jiménez; E. García-Bustamante; J. F. González-Rouco; F. Valero; J. P. Montávez; J. Navarro

2008-01-01T23:59:59.000Z

206

Modelling of offshore wind turbine wakes with the wind farm program FLaP  

E-Print Network [OSTI]

Modelling of offshore wind turbine wakes with the wind farm program FLaP Bernhard Lange(1) , Hans been extended to improve the description of wake development in offshore conditions, especially the low from the Danish offshore wind farm Vindeby. Vertical wake profiles and mean turbulence intensities

Heinemann, Detlev

207

NREL: Wind Research - Grid Integration of Offshore Wind  

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

Grid Integration of Offshore Wind Grid Integration of Offshore Wind Photograph of a wind turbine in the ocean. Located about 10 kilometers off the coast of Arklow, Ireland, the Arklow Bank offshore wind park consists of seven GE Wind 3.6-MW wind turbines. Much can be learned from the existing land-based integration research for handling the variability and uncertainty of the wind resource. Integration and Transmission One comprehensive grid integration study is the Eastern Wind Integration and Transmission Study (EWITS), in which offshore wind scenarios were analyzed. Nearly 80 GW of offshore wind was studied in the highest penetration scenario. Specific offshore grid distribution and transmission solutions were identified, including cost estimates. With the Atlantic coast likely to lead the way in offshore wind power deployment, EWITS is a benchmark for

208

Resolved Turbulence Characteristics in Large-Eddy Simulations Nested within Mesoscale Simulations Using the Weather Research and Forecasting Model  

Science Journals Connector (OSTI)

One-way concurrent nesting within the Weather Research and Forecasting Model (WRF) is examined for conducting large-eddy simulations (LES) nested within mesoscale simulations. Wind speed, spectra, and resolved turbulent stresses and turbulence ...

Jeff Mirocha; Branko Kosovi?; Gokhan Kirkil

2014-02-01T23:59:59.000Z

209

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

210

INTERCHANGE RECONNECTION IN A TURBULENT CORONA  

SciTech Connect (OSTI)

Magnetic reconnection at the interface between coronal holes and loops, the so-called interchange reconnection, can release the hotter, denser plasma from magnetically confined regions into the heliosphere, contributing to the formation of the highly variable slow solar wind. The interchange process is often thought to develop at the apex of streamers or pseudo-streamers, near Y- and X-type neutral points, but slow streams with loop composition have been recently observed along fanlike open field lines adjacent to closed regions, far from the apex. However, coronal heating models, with magnetic field lines shuffled by convective motions, show that reconnection can occur continuously in unipolar magnetic field regions with no neutral points: photospheric motions induce a magnetohydrodynamic turbulent cascade in the coronal field that creates the necessary small scales, where a sheared magnetic field component orthogonal to the strong axial field is created locally and can reconnect. We propose that a similar mechanism operates near and around boundaries between open and closed regions inducing a continual stochastic rearrangement of connectivity. We examine a reduced magnetohydrodynamic model of a simplified interface region between open and closed corona threaded by a strong unipolar magnetic field. This boundary is not stationary, becomes fractal, and field lines change connectivity continuously, becoming alternatively open and closed. This model suggests that slow wind may originate everywhere along loop-coronal-hole boundary regions and can account naturally and simply for outflows at and adjacent to such boundaries and for the observed diffusion of slow wind around the heliospheric current sheet.

Rappazzo, A. F.; Matthaeus, W. H. [Bartol Research Institute, Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Ruffolo, D. [Department of Physics, Faculty of Science, Mahidol University, Bangkok 10400 (Thailand); Servidio, S. [Dipartimento di Fisica, Universita della Calabria, I-87036 Cosenza (Italy); Velli, M., E-mail: rappazzo@udel.edu [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

2012-10-10T23:59:59.000Z

211

Quantifying Turbulence for Tidal Power Applications  

SciTech Connect (OSTI)

Using newly collected data from a tidal power site in Puget Sound, WA, metrics for turbulence quantification are assessed and discussed. The quality of raw ping Acoustic Doppler Current Profiler (ADCP) data for turbulence studies is evaluated against Acoustic Doppler Velocimeter (ADV) data at a point. Removal of Doppler noise from the raw ping data is shown to be a crucial step in turbulence quantification. Excluding periods of slack tide, the turbulent intensity estimates at a height of 4.6 m above the seabed are 8% and 11% from the ADCP and ADV, respectively. Estimates of the turbulent dissipation rate are more variable, from 10e-3 to 10e-1 W/m^3. An example analysis of coherent Turbulent Kinetic Energy (TKE) is presented.

Thomson, Jim; Richmond, Marshall C.; Polagye, Brian; Durgesh, Vibhav

2010-08-01T23:59:59.000Z

212

Turbulent combustion  

SciTech Connect (OSTI)

Turbulent combustion is the dominant process in heat and power generating systems. Its most significant aspect is to enhance the burning rate and volumetric power density. Turbulent mixing, however, also influences the chemical rates and has a direct effect on the formation of pollutants, flame ignition and extinction. Therefore, research and development of modern combustion systems for power generation, waste incineration and material synthesis must rely on a fundamental understanding of the physical effect of turbulence on combustion to develop theoretical models that can be used as design tools. The overall objective of this program is to investigate, primarily experimentally, the interaction and coupling between turbulence and combustion. These processes are complex and are characterized by scalar and velocity fluctuations with time and length scales spanning several orders of magnitude. They are also influenced by the so-called {open_quotes}field{close_quotes} effects associated with the characteristics of the flow and burner geometries. The authors` approach is to gain a fundamental understanding by investigating idealized laboratory flames. Laboratory flames are amenable to detailed interrogation by laser diagnostics and their flow geometries are chosen to simplify numerical modeling and simulations and to facilitate comparison between experiments and theory.

Talbot, L.; Cheng, R.K. [Lawrence Berkeley Laboratory, CA (United States)

1993-12-01T23:59:59.000Z

213

Wind derivatives: hedging wind risk:.  

E-Print Network [OSTI]

??Wind derivatives are financial contracts that can be used to hedge or mitigate wind risk. In this thesis, the focus was on pricing these wind… (more)

Hoyer, S.A.

2013-01-01T23:59:59.000Z

214

CONNECTING THE SUN'S HIGH-RESOLUTION MAGNETIC CARPET TO THE TURBULENT HELIOSPHERE  

SciTech Connect (OSTI)

The solar wind is connected to the Sun's atmosphere by flux tubes that are rooted in an ever-changing pattern of positive and negative magnetic polarities on the surface. Observations indicate that the magnetic field is filamentary and intermittent across a wide range of spatial scales. However, we do not know to what extent the complex flux-tube topology seen near the Sun survives as the wind expands into interplanetary space. In order to study the possible long-distance connections between the corona and the heliosphere, we developed new models of turbulence-driven solar wind acceleration along empirically constrained field lines. We used a potential field model of the quiet Sun to trace field lines into the ecliptic plane with unprecedented spatial resolution at their footpoints. For each flux tube, a one-dimensional model was created with an existing wave/turbulence code that solves equations of mass, momentum, and energy conservation from the photosphere to 4 AU. To take account of stream-stream interactions between flux tubes, we used those models as inner boundary conditions for a time-steady magnetohydrodynamic description of radial and longitudinal structure in the ecliptic. Corotating stream interactions smear out much of the smallest-scale variability, making it difficult to see how individual flux tubes on granular or supergranular scales can survive out to 1 AU. However, our models help clarify the level of ''background'' variability with which waves and turbulent eddies should be expected to interact. Also, the modeled fluctuations in magnetic field magnitude were seen to match measured power spectra quite well.

Cranmer, Steven R.; Van Ballegooijen, Adriaan A.; Woolsey, Lauren N. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2013-04-20T23:59:59.000Z

215

Community Wind: Once Again Pushing the Envelope of Project Finance  

E-Print Network [OSTI]

lease financing has been popular in the commercial solarlease financing in the wind sector due to wind power’s greater inter-year variability relative to solar (

bolinger, Mark A.

2011-01-01T23:59:59.000Z

216

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 Peña; Charlotte Bay Hasager; Sven-Erik Gryning; Michael Courtney; Ioannis Antoniou; Torben Mikkelsen; Paul Sørensen

2007-01-01T23:59:59.000Z

217

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

218

Generation of large-scale winds in horizontally anisotropic convection  

E-Print Network [OSTI]

We simulate three-dimensional, horizontally periodic Rayleigh-B\\'enard convection between free-slip horizontal plates, rotating about a horizontal axis. When both the temperature difference between the plates and the rotation rate are sufficiently large, a strong horizontal wind is generated that is perpendicular to both the rotation vector and the gravity vector. The wind is turbulent, large-scale, and vertically sheared. Horizontal anisotropy, engendered here by rotation, appears necessary for such wind generation. Most of the kinetic energy of the flow resides in the wind, and the vertical turbulent heat flux is much lower on average than when there is no wind.

von Hardenberg, J; Provenzale, A; Spiegel, E A

2015-01-01T23:59:59.000Z

219

Scaling turbulent atmospheric stratification: a turbulence/wave wind model  

E-Print Network [OSTI]

, it displays no wave-like phenomenol- ogy. We show how to extend the FIF model to account for more realistic

Lovejoy, Shaun

220

Mean and peak wind loads on heliostats  

SciTech Connect (OSTI)

Mean and peak wind loads on flat rectangular or circular heliostats were measured on models in a boundary layer wind tunnel which included an atmospheric surface layer simulation. Horizontal and vertical forces, moments about horizontal axes at the ground level and at the centerline of the heliostat, and the moment about the vertical axis through the heliostat center were measured. Results showed that loads are higher than predicted from results obtained in a uniform, low-turbulence flow due to the presence of turbulence. Reduced wind loads were demonstrated for heliostats within a field of heliostats and upper bound curves were developed to provide preliminary design coefficients.

Peterka, J.A.; Tan, Z.; Cermak, J.E.; Bienkiewicz, B.

1989-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "turbulence wind variability" 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

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

222

6, 52515268, 2006 Turbulent fluxes over  

E-Print Network [OSTI]

´exico, 04510 Mexico City, Mexico Received: 24 March 2006 ­ Accepted: 10 May 2006 ­ Published: 26 June 2006 wind speed conditions (up to 25 ms -1 ). The estimates of total momentum flux and turbulent kinetic energy can be represented very5 accurately (r2 =0.99, when data are binned every 1 ms-1 ) by empirical

Boyer, Edmond

223

Ris-R-1239(EN) Wind Energy Department  

E-Print Network [OSTI]

Risø-R-1239(EN) Wind Energy Department: Scientific and Technical Progress 1999 - 2000 Birthe The activities of the Wind Energy Department fall within boundary layer meteorology, atmospheric turbulence-R-1239(EN) 3 Contents 1 Introduction 5 2 The Department of Wind Energy and Atmospheric Physics 5 3

224

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

225

Passive Tomography of Turbulence Strength Marina Alterman1  

E-Print Network [OSTI]

expensive. Turbulence significantly affects the efficiency of wind turbine #12;2 M. Alterman, Y. Y), wind, and atmospheric stability. This is measured using special Doppler lidars [9, 31], which are very. Schechner, M. Vo and S. G. Narasimhan farms [31], hence optimizing turbines and farms involves measuring TS

Sheikh, Yaser Ajmal

226

Modeling of wind and radar for simulation in four-dimensional navigation environment  

E-Print Network [OSTI]

Disturbances affecting time control precision in four-dimension navigation are modeled. Several models of wind and turbulence from the ground to ten thousand feet are developed. A distinction is made between wind mean and ...

Malherbe, Gerard Andre

1976-01-01T23:59:59.000Z

227

Economic and technical impacts of wind variability and intermittency on long-term generation expansion planning in the U.S  

E-Print Network [OSTI]

Electricity power systems are a major source of carbon dioxide emissions and are thus required to change dramatically under climate policy. Large-scale deployment of wind power has emerged as one key driver of the shift ...

Brun, Caroline Elisabeth Hénia

2011-01-01T23:59:59.000Z

228

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

229

Capability constraints to mitigate voltage fluctuations from DFIG wind farms when delivering ancillary services to the network  

Science Journals Connector (OSTI)

Abstract Majority of the wind power resources are typically sited at remote locations in power networks and generated power is transmitted through rural transmission corridors to load centres. With increased penetration level of the wind generation there is an increased requirement to provide ancillary services from distributed wind power resources, hence they are operated under different control strategies to provide ancillary services to the network. The control strategies and capability characteristics will significant impact on voltage fluctuations in distribution networks. This paper presents a comparative analysis between different wind generator control strategies (i.e. power factor control strategy, voltage control strategy and reactive power dispatch strategy) on network voltage fluctuations during variable wind conditions while considering extended reactive power capability (i.e. with both generator and power electronic converter reactive power capabilities) for the doubly-fed induction generator (DFIG). Voltage fluctuations are analysed using real wind data measured at a DFIG based wind farm, and the wind farm model was verified against real measurements. Study has shown that voltage fluctuations are exacerbated when wind generator is at mode transition (i.e. from power optimisation mode to power limitation mode). A sensitivity analysis has shown that voltage fluctuations are exacerbated due to the limitations of the reactive power capability of the DFIG, and the operating point of the DFIG power curve irrespective of the control strategy implemented at the wind generator. Furthermore, a mitigation strategy was developed as an integrated control scheme to the main control scheme in order to reduce voltage fluctuations due to wind power variations. However, effectiveness of the mitigation strategy is greatly affected by the reactive power capability of the DFIG, in particular during high wind turbulences.

Lasantha Meegahapola; Sarath Perera

2014-01-01T23:59:59.000Z

230

Wind shear for large wind turbine generators at selected tall tower sites  

SciTech Connect (OSTI)

The objective of the study described in this report is to examine the nature of wind shear profiles and their variability over the height of large horizontal-axis wind turbines and to provide information on wind shear relevant to the design and opertion of large wind turbines. Wind turbine fatigue life and power quality are related through the forcing functions on the blade to the shapes of the wind shear profiles and their fluctuations over the disk of rotation.

Elliott, D.L.

1984-04-01T23:59:59.000Z

231

Estimation of uncertainties due to the wind-induced noise in a screened microphone  

E-Print Network [OSTI]

for experimental assessment of wind turbine noise. The contribution of the wind noise introduces a biasEstimation of uncertainties due to the wind-induced noise in a screened microphone D. Ecotiere by the wind at a screened microphone. This noise originates from turbulences that come from the direct

Paris-Sud XI, Université de

232

AIAA-2004-0502 A COMPARISON OF WIND TURBINE DESIGN LOADS IN DIFFERENT  

E-Print Network [OSTI]

in the gross wind environment and in the extreme response given wind conditions to establish nominal designAIAA-2004-0502 1 A COMPARISON OF WIND TURBINE DESIGN LOADS IN DIFFERENT ENVIRONMENTS USING INVERSE, Austin, TX 78712 ABSTRACT* The influence of turbulence conditions on the design loads for wind turbines

Manuel, Lance

233

WIND ENERGY Wind Energ. (2014)  

E-Print Network [OSTI]

WIND ENERGY Wind Energ. (2014) Published online in Wiley Online Library (wileyonlinelibrary Correspondence M. Wächter, ForWind-Center for Wind Energy Research, Institute of Physics, Carl Von Ossietzky on the operation of wind energy converters (WECs) imposing different risks especially in terms of highly dynamic

Peinke, Joachim

234

Comparison of anemometers for turbulence characterization  

SciTech Connect (OSTI)

During the first phase of the US Department of Energy's turbulence characterization program, important discoveries were made about the field application of propeller-vane and cup anemometers under very turbulent conditions. First, averaged speeds measured by the propeller-vane anemometer were consistently lower than those from the cup anemometer, even though both registered virtually the same during wind-tunnel calibration testing. Second, the propeller-vane anemometers suffered from structural failures much more frequently than the cup anemometers. The difficulties associated with the use of the propeller-vane motivated us to consider the cup anemometer for turbulence measurements. At fast sample rates, the output of the cup anemometer is severely degraded by discretization error that stems from pulse counting demodulation. However, we found that a low-pass Gaussian filter could be applied to the time series of wind speed derived from the cup anemometer to yield time series and frequency spectra that compared very favorably with those obtained from the propeller-vane anemometer. This finding suggests that the cup anemometer may prove to be an inexpensive and rugged sensor appropriate for turbulence measurements for wind-energy applications.

Morris, V.R.; Barnard, J.C.; Wendell, L.L.; Tomich, S.D.

1992-10-01T23:59:59.000Z

235

wind energy  

National Nuclear Security Administration (NNSA)

5%2A en Pantex to Become Wind Energy Research Center http:nnsa.energy.govfieldofficesnponpopressreleasespantex-become-wind-energy-research-center

236

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

237

Enhanced Dispersion from Tall Stacks Near Modern Wind Mills  

Science Journals Connector (OSTI)

Dispersion modeling of emissions from tall stacks is often done with regulatory models, based on the Gaussian plume concept. When the plumes of tall stacks are influenced by the turbulence of nearby wind mills, t...

J. J. Erbrink; Luc Verhees

2014-01-01T23:59:59.000Z

238

The interaction of katabatic winds and mountain waves  

SciTech Connect (OSTI)

The variation in the oft-observed, thermally-forced, nocturnal katabatic winds along the east side of the Rocky Mountains can be explained by either internal variability or interactions with various other forcings. Though generally katabatic flows have been studied as an entity protected from external forcing by strong thermal stratification, this work investigates how drainage winds along the Colorado Front Range interact with, in particular, topographically forced mountain waves. Previous work has shown, based on measurements taken during the Atmospheric Studies in Complex Terrain 1993 field program, that the actual dispersion in katabatic flows is often greater than reflected in models of dispersion. The interaction of these phenomena is complicated and non-linear since the amplitude, wavelength and vertical structure of mountain waves developed by flow over the Rocky Mountain barrier are themselves partly determined by the evolving atmospheric stability in which the drainage flows develop. Perturbations to katabatic flow by mountain waves, relative to their more steady form in quiescent conditions, are found to be caused by both turbulence and dynamic pressure effects. The effect of turbulent interaction is to create changes to katabatic now depth, katabatic flow speed, katabatic jet height and, vertical thermal stratification. The pressure effect is found to primarily influence the variability of a given katabatic now through the evolution of integrated column wave forcing on surface pressure. Variability is found to occur on two scales, on the mesoscale due to meso-gamma scale mountain wave evolution, and on the microscale, due to wave breaking. Since existing parameterizations for the statically stable case are predominantly based on nearly flat terrain atmospheric measurements under idealized or nearly quiescent conditions, it is no surprise that these parameterizations often contribute to errors in prediction, particularly in complex terrain.

Poulos, G.S.

1997-01-01T23:59:59.000Z

239

COMPARISON OF WIND AND WIND SHEAR CLIMATOLOGIES DERIVED FROM HIGH-RESOLUTION RADIOSONDES AND THE ECMWF MODEL  

E-Print Network [OSTI]

COMPARISON OF WIND AND WIND SHEAR CLIMATOLOGIES DERIVED FROM HIGH-RESOLUTION RADIOSONDES wind and its vertical gradient, i.e. wind-shear, is characterized as a function of climate region. For a better representation of the average atmospheric wind and shear and their variabilities, high

Stoffelen, Ad

240

Wind Energy  

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

FUPWG Meeting FUPWG Meeting NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy operated by the Alliance for Sustainable Energy, LLC Robi Robichaud November 18, 2009 Topics Introduction Review of the Current Wind Market Drivers for Wind Development Siting g Issues Wind Resource Assessment Wind Characteristics Wind Power Potential Basic Wind Turbine Theory Basic Wind Turbine Theory Types of Wind Turbines Facts About Wind Siting Facts About Wind Siting Wind Performance 1. United States: MW 1 9 8 2 1 9 8 3 1 9 8 4 1 9 8 5 1 9 8 6 1 9 8 7 1 9 8 8 1 9 8 9 1 9 9 0 1 9 9 1 1 9 9 2 1 9 9 3 1 9 9 4 1 9 9 5 1 9 9 6 1 9 9 7 1 9 9 8 1 9 9 9 2 0 0 0 2 0 0 1 2 0 0 2 2 0 0 3 2 0 0 4 2 0 0 5 2 0 0 6 2 0 0 7 2 0 0 8 Current Status of the Wind Industry Total Global Installed Wind Capacity Total Global Installed Wind Capacity Total Global Installed Wind Capacity

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


241

A Multiscale Wind and Power Forecast System for Wind Farms  

Science Journals Connector (OSTI)

Abstract A large scale introduction of wind energy in power sector causes a number of challenges for electricity market and wind farm operators who will have to deal with the variability and uncertainty in the wind power generation in their scheduling and trading decisions. Numerical wind power forecasting has been identified as an important tool to address the increasing variability and uncertainty and to more efficiently operate power systems with large wind power penetration. It has been observed that even when the wind magnitude and direction recorded at a wind mast are the same, the corresponding energy productions can vary significantly. In this work we try to introduce improvements by developing a more accurate wind forecast system for a complex terrain. The system has been operational for eight months for the Bessaker Wind Farm located in the middle part of Norway in a very complex terrain. Operational power curves have also been derived from data analysis. Although the methodology explained has been developed for an onshore wind farm, it can very well be utilized in an offshore context also.

Adil Rasheed; Jakob Kristoffer Süld; Trond Kvamsdal

2014-01-01T23:59:59.000Z

242

ASYMMETRIC SOLAR WIND ELECTRON DISTRIBUTIONS  

SciTech Connect (OSTI)

The present paper provides a possible explanation for the solar wind electron velocity distribution functions possessing asymmetric energetic tails. By numerically solving the electrostatic weak turbulence equations that involve nonlinear interactions among electrons, Langmuir waves, and ion-sound waves, it is shown that different ratios of ion-to-electron temperatures lead to the generation of varying degrees of asymmetric tails. The present finding may be applicable to observations in the solar wind near 1 AU and in other regions of the heliosphere and interplanetary space.

Yoon, Peter H.; Kim, Sunjung; Lee, Junggi; Lee, Junhyun; Park, Jongsun; Park, Kyungsun; Seough, Jungjoon [School of Space Research, Kyung Hee University, Yongin-Si, Gyeonggi-Do 446-701 (Korea, Republic of); Hong, Jinhy [Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of)

2012-08-20T23:59:59.000Z

243

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

244

Quantitative visualization of compressible turbulent shear flows using condensate-enhanced Rayleigh scattering  

E-Print Network [OSTI]

was based on laser scattering from particles of H2O or CO2 condensate that form in the wind tunnel nozzleQuantitative visualization of compressible turbulent shear flows using condensate-enhanced Rayleigh

Miles, Richard

245

Turbulent flow in graphene  

E-Print Network [OSTI]

We demonstrate the possibility of a turbulent flow of electrons in graphene in the hydrodynamic region, by calculating the corresponding turbulent probability density function. This is used to calculate the contribution of the turbulent flow to the conductivity within a quantum Boltzmann approach. The dependence of the conductivity on the system parameters arising from the turbulent flow is very different from that due to scattering.

Kumar S. Gupta; Siddhartha Sen

2009-11-03T23:59:59.000Z

246

NREL: Wind Research - Utility Grid Integration  

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

Utility Grid Integration Utility Grid Integration Photo of a wind farm in Lawton, Oklahoma where NREL researchers studied the impact of wind energy on farming system operations. NREL researchers analyzed research data collected from this wind farm in Lawton, Oklahoma, to determine the impacts of wind energy on systems operations. NREL researchers analyzed research data collected from this wind farm in Lawton, Oklahoma, to determine the impacts of wind energy on systems operations. The integration of wind energy into the electric generation industry's supply mix is one of the issues industry grapples with. The natural variability of the wind resource raises concerns about how wind can be integrated into routine grid operations, particularly with regard to the effects of wind on regulation, load following, scheduling, line voltage,

247

Passively cooled direct drive wind turbine  

DOE Patents [OSTI]

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

Costin, Daniel P. (Chelsea, VT)

2008-03-18T23:59:59.000Z

248

Turbulent phenomena in protein folding  

Science Journals Connector (OSTI)

Protein folding and hydrodynamic turbulence are two long-standing challenges, in molecular biophysics and fluid dynamics, respectively. The theories of these phenomena have been developed independently and used different formalisms. Here we show that the protein folding flows can be surprisingly similar to turbulent fluid flows. Studying a benchmark model protein (an SH3 domain), we have found that the flows for the slow folding trajectories of the protein, in which a partly formed N- and C-terminal ? sheet hinders the RT loop from attaching to the protein core, have many properties of turbulent flows of a fluid. The flows are analyzed in a three-dimensional (3D) space of collective variables, which are the numbers of native contacts between the terminal ? strands, between the RT loop and the protein core, and the rest of the native contacts. We have found that the flows have fractal nature and are filled with 3D eddies; the latter contain strange attractors, at which the tracer flow paths behave as saddle trajectories. Two regions of the space increment have been observed, in which the flux variations are self-similar with the scaling exponent h=1/3, in surprising agreement with the Kolmogorov inertial range theory of turbulence. In one region, the cascade of protein rearrangements is directed from larger to smaller scales (net folding), and in the other, it is oppositely directed (net unfolding). Folding flows for the fast trajectories are essentially “laminar” and do not have the property of self-similarity. Based on the results of our study, we infer, and support this inference by simulations, that the origin of the similarity between the protein folding and turbulent motion of a fluid is in a cascade mechanism of structural transformations in the systems that underlies these phenomena.

Igor V. Kalgin and Sergei F. Chekmarev

2011-01-31T23:59:59.000Z

249

Wind Mills  

Science Journals Connector (OSTI)

Over 5,000 years ago, the ancient Egyptians used wind to sail ships on the Nile River. While the proliferation of water mills was in full swing, windmills appeared to harness more inanimate energy by employing wind

J. S. Rao

2011-01-01T23:59:59.000Z

250

Wind Farm  

Office of Energy Efficiency and Renewable Energy (EERE)

The wind farm in Greensburg, Kansas, was completed in spring 2010, and consists of ten 1.25 megawatt (MW) wind turbines that supply enough electricity to power every house, business, and municipal...

251

Wind Power  

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

Wind Power As the accompanying map of New Mexico shows, the best wind power generation potential near WIPP is along the Delaware Mountain ridge line of the southern Guadalupe...

252

Wind Power  

Science Journals Connector (OSTI)

For off-shore wind energy, it is not economically profitable to locate wind turbines in waters with depths larger than about 40 m. For this reason, some floating turbine prototypes are being tested, which can be ...

Ricardo Guerrero-Lemus; José Manuel Martínez-Duart

2013-01-01T23:59:59.000Z

253

New England Wind Forum: Technical Challenges  

Wind Powering America (EERE)

Technical Challenges Technical Challenges Wind power is by its nature variable, and as a result, it differs from the majority of generation supplying the electric grid. Aspects of this variability are often cited as shortcomings. For instance, the fact that wind power will not be as regularly and reliably available at system peak times as most other generators is sometimes used to argue that wind power requires additional backup resources by other generation on a one-to-one basis. And wind's relatively low capacity factor (a ratio of the total energy output relative to the theoretical sustained peak output) is sometimes used to characterize wind generators as inefficient. It's been stated that other generation will have to be operated in such an inefficient manner to react to wind that it will not reduce fossil fuel usage or emissions. Here we address concerns that wind power's variability will eradicate any expected benefit.

254

Under consideration for publication in J. Fluid Mech. 1 Realizing turbulent statistics  

E-Print Network [OSTI]

be reproduced at the inflow?". We present a technique able to produce a random field with the exact two on our system. Suppose that we are interested in the wake of a cylinder in a fully turbulent flow, as could be realized experimentally by placing a turbulence generating grid in a wind tunnel, upstream

Hoepffner, Jérôme

255

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

E-Print Network [OSTI]

Makarov, Y. , 2007: Wind Integration Issues and So- lutionsexpectations, and integration strategy for any wind powerwind climate and variability. Site design and operation, as well as market integration

Mansbach, David K.

2010-01-01T23:59:59.000Z

256

E-Print Network 3.0 - aggregated wind power Sample Search Results  

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

and the increased wind power penetration in power systems the main trend for modern wind turbines is clearly... variable speed operation and grid connection via ... Source: Ris...

257

The effect of high penetration of wind power on primary frequency control of power systems.  

E-Print Network [OSTI]

??In this work, a power system with wind power units and hydro power units are considered. The hydro power unit and variable speed wind turbine… (more)

Motamed, Bardia

2013-01-01T23:59:59.000Z

258

Nonlinear wave evolution in the expanding solar wind  

Science Journals Connector (OSTI)

We report here on a numerical model allowing direct numerical simulations of magnetohydrodynamic fluctuations advected by the expanding solar wind. We show that the expansion of the plasma delays and possibly freezes the turbulent evolution, but that it also triggers the nonlinear evolution of otherwise stable (Alfvén) waves, which can thus release their energy in the wind.

Roland Grappin; Marco Velli; André Mangeney

1993-04-05T23:59:59.000Z

259

Distributed Wind Energy in Idaho  

SciTech Connect (OSTI)

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

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

2009-01-31T23:59:59.000Z

260

Wind energy  

Science Journals Connector (OSTI)

...is approximately 4.5-6.01 for onshore wind farms. The price for offshore wind farms is estimated to be 50% higher. For comparison...visually intrusive. The visual impact of offshore wind farms quickly diminishes with distance and 10km...

2007-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "turbulence wind variability" 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

‘Chinook winds  

Science Journals Connector (OSTI)

...of south-easterly winds, which blow over the...Ocean, from which the winds come, can at this season...freezing-point. The wind well known in the Alps as the foehn is another example of...result is complicated by local details; regions of...

George M. Dawson

1886-01-08T23:59:59.000Z

262

On specification of initial conditions in turbulence models  

SciTech Connect (OSTI)

Recent research has shown that initial conditions have a significant influence on the evolution of a flow towards turbulence. This important finding offers a unique opportunity for turbulence control, but also raises the question of how to properly specify initial conditions in turbulence models. We study this problem in the context of the Rayleigh-Taylor instability. The Rayleigh-Taylor instability is an interfacial fluid instability that leads to turbulence and turbulent mixing. It occurs when a light fluid is accelerated in to a heavy fluid because of misalignment between density and pressure gradients. The Rayleigh-Taylor instability plays a key role in a wide variety of natural and man-made flows ranging from supernovae to the implosion phase of Inertial Confinement Fusion (ICF). Our approach consists of providing the turbulence models with a predicted profile of its key variables at the appropriate time in accordance to the initial conditions of the problem.

Rollin, Bertrand [Los Alamos National Laboratory; Andrews, Malcolm J [Los Alamos National Laboratory

2010-12-01T23:59:59.000Z

263

Lidar-based Research and Innovation at DTU Wind Energy – a Review  

Science Journals Connector (OSTI)

As wind turbines during the past decade have increased in size so have the challenges met by the atmospheric boundary-layer meteorologists and the wind energy society to measure and characterize the huge-volume wind fields surpassing and driving them. At the DTU Wind Energy test site "Østerild" for huge wind turbines, the hub-height of a recently installed 8 MW Vestas V164 turbine soars 143 meters up above the ground, and its rotor of amazing 164 meters in diameter make the turbine tips flicker 225 meters into the sky. Following the revolution in photonics-based telecommunication at the turn of the Millennium new fibre-based wind lidar technologies emerged and DTU Wind Energy, at that time embedded within Rise National Laboratory, began in collaboration with researchers from wind lidar companies to measure remote sensed wind profiles and turbulence structures within the atmospheric boundary layer with the emerging, at that time new, all-fibre-based 1.55 ? coherent detection wind lidars. Today, ten years later, DTU Wind Energy routinely deploys ground-based vertical profilers instead of met masts for high-precision measurements of mean wind profiles and turbulence profiles. At the departments test site "Høvsøre" DTU Wind Energy also routinely calibrate and accredit wind lidar manufactures wind lidars. Meanwhile however, new methodologies for power curve assessment based on ground-based and nacelle based lidars have also emerged. For improving the turbines power curve assessments and for advancing their control with feed-forward wind measurements experience has also been gained with wind lidars installed on turbine nacelles and integrated into the turbines rotating spinners. A new mobile research infrastructure WindScanner.dk has also emerged at DTU Wind Energy. Wind and turbulence fields are today scanned from sets of three simultaneously in space and time synchronized scanning lidars. One set consists of three fast scanning continuous-wave based wind lidars (short-range system), and another consisting of three synchronized pulsed wind lidar systems (long-range system). Today, wind lidar profilers and WindScanners are routinely deployed and operated during field tests and measurement campaigns. Lidars have been installed and operated from ground, on offshore platforms, and also as scanning lidars integrated in operating turbines. As a result, wind profiles and also detailed 3D scanning of wind and turbulence fields have been achieved: 1) of the free wind aloft, 2) over complex terrain, 3) at coastal ranges with land-sea interfaces, 4) offshore, 5) in turbine inflow induction zone, and 6) of the complex and turbulent flow fields in the wakes inside wind parks.

T Mikkelsen

2014-01-01T23:59:59.000Z

264

Advances in three-dimensional turbulence measurement capability  

SciTech Connect (OSTI)

Requirements for three-dimensional turbulence velocity measurements for wind turbine purposes have recently led to advances in anemometer accuracy and resolution, particularly for situations when the angle of the wind relative to the anemometer axis is large. New precision calibration data for a complete three-dimensional UVW propeller anemometer are presented. Repeatability of calibration data and comparison with previous calibrations are shown. Special attention is given to the calibration of the crosswind components, V and W. 4 refs., 9 figs.

Connell, J.R.; Morris, V.R.

1988-11-01T23:59:59.000Z

265

NREL: Wind Research - Computer-Aided Engineering Tools  

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

Computer-Aided Engineering Tools Computer-Aided Engineering Tools Illustration of an offshore wind turbine on a barge with an illustration of how the moorings would work. A simulation of a 5-MW wind turbine on an offshore semi-submersible with catenary moorings. The National Wind Technology Center (NWTC) at NREL develops advanced computer-aided engineering (CAE) tools to support the wind and water power industries with state-of-the-art design and analysis capabilities. We have developed many software tools that produce realistic models that simulate the behavior of wind and water power technologies in complex environments-storm winds, waves offshore, earthquake loading, and extreme turbulence-and model the effects of turbulent inflow, unsteady aerodynamic forces, structural dynamics, drivetrain response, control

266

Wind Blog  

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

wind-blog Office of Energy Efficiency & Renewable wind-blog Office of Energy Efficiency & Renewable Energy Forrestal Building 1000 Independence Avenue, SW Washington, DC 20585 en Two Facilities, One Goal: Advancing America's Wind Industry http://energy.gov/eere/articles/two-facilities-one-goal-advancing-america-s-wind-industry wind-industry" class="title-link">Two Facilities, One Goal: Advancing America's Wind Industry

267

Operational Impacts of Large Deployments of Offshore Wind (Poster)  

SciTech Connect (OSTI)

The potential operational impact of deploying 54 GW of offshore wind in the United States was examined. The capacity was not evenly distributed; instead, it was concentrated in regions with better wind quality and close to load centers (Table 1). A statistical analysis of offshore wind power time series was used to assess the effect on the power system. The behavior of offshore wind resembled that of onshore wind, despite the former presenting higher capacity factors, more consistent power output across seasons, and higher variability levels. Thus, methods developed to manage onshore wind variability can be extended and applied to offshore wind.

Ibanez, E.; Heaney, M.

2014-10-01T23:59:59.000Z

268

Research papers Observations over an annual cycle and simulations of wind-forced  

E-Print Network [OSTI]

Research papers Observations over an annual cycle and simulations of wind-forced oscillations near Turbulence Model (GOTM) 1-D simulations of diurnal wind forcing, including the first order coast breeze Diurnal wind Namibia Benguela current a b s t r a c t Sea breezes are characteristic features

Gille, Sarah T.

269

American Institute of Aeronautics and Astronautics A Framework for the Reliability Analysis of Wind Turbines  

E-Print Network [OSTI]

of Wind Turbines against Windstorms and Non-Standard Inflow Definitions Lance Manuel1 Dept. of Civil typical wind turbine systems are yet to be characterized in ways that drive aeroelastic loads and design., but the coherence structure and turbulence kinetics at the spatial scale of wind turbine rotors are not as well

Manuel, Lance

270

Ris DTU Dec.3 2009WindScanner.eu 1 Ris DTU, Technical University of Denmark  

E-Print Network [OSTI]

engulfing today's and tomorrows huge on and offshore wind turbines. - a brig less RI for renewable energy IWES (onshore sites, Alpha Ventus ­ FINO 1- 3 offshore) · Norway: SINTEF (offshore technology, floatingScanner.eu Envisioned new RI European Centre for Wind Energy Research in Atmospheric Turbulent Flow "The Wind

271

Evidence for Inhomogeneous Heating in the Solar Wind  

Science Journals Connector (OSTI)

Solar wind observations and magnetohydrodynamic (MHD) simulations are used to probe the nature of turbulence heating. In particular, the electron heat flux, electron temperature, and ion temperature in the solar wind are studied using ACE and Wind data. These heating diagnostics are also compared with MHD simulation estimates of the local dissipation density. Coherent structures, which are sources of inhomogeneity and intermittency in MHD turbulence, are found to be associated with enhancements in every heating-related diagnostic. This supports the hypothesis that significant inhomogeneous heating occurs in the solar wind, connected with current sheets that are dynamically generated by MHD turbulence. Indeed, a subset of these coherent current sheets might be candidates for magnetic reconnection. However, the specific kinetic mechanisms that heat and accelerate particles within these structures require further study.

K. T. Osman; W. H. Matthaeus; A. Greco; S. Servidio

2011-01-01T23:59:59.000Z

272

Automatic storm protection control for wind energy system  

SciTech Connect (OSTI)

A wind energy plant is protected against damage from high winds by permitting the propeller assembly thereof to fold with respect to the tail assembly of the plant when the wind velocity with respect to the plant exceeds a predetermined value. Return of the propeller assembly to a wind facing orientation is controlled to prevent oscillating or whipping in gusty or turbulent winds. A safety system is included to control plant shutdown, and automatically shuts down the plant if the plant is being subjected to excessive vibration.

Jacobs, M.L.; Jacobs, P.R.

1981-10-27T23:59:59.000Z

273

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

274

Operating wind turbines in strong wind conditions by using feedforward-feedback control  

Science Journals Connector (OSTI)

Due to the increasing penetration of wind energy into power systems, it becomes critical to reduce the impact of wind energy on the stability and reliability of the overall power system. In precedent works, Shen and his co-workers developed a re-designed operation schema to run wind turbines in strong wind conditions based on optimization method and standard PI feedback control, which can prevent the typical shutdowns of wind turbines when reaching the cut-out wind speed. In this paper, a new control strategy combing the standard PI feedback control with feedforward controls using the optimization results is investigated for the operation of variable-speed pitch-regulated wind turbines in strong wind conditions. It is shown that the developed control strategy is capable of smoothening the power output of wind turbine and avoiding its sudden showdown at high wind speeds without worsening the loads on rotor and blades.

Ju Feng; Wen Zhong Sheng

2014-01-01T23:59:59.000Z

275

Turbulent Erosion Of Persistent Cold-Air Pools: Numerical Simulations  

Science Journals Connector (OSTI)

High-resolution idealized numerical simulations are used to examine the turbulent removal of cold-air pools commonly observed in mountain valleys and basins. A control simulation with winds aloft increasing from 0.5 to 20 m s-1 over 20 h combined ...

Neil P. Lareau; John D. Horel

276

Kinematics of Turbulence Convected by a Random Wave Field  

Science Journals Connector (OSTI)

Turbulent velocity spectra measured beneath wind waves show a large enhancement about the central wave frequency. A “5/3" frequency dependence can be seen both above and below the central peak, but with an apparent increase in spectral density at ...

J. L. Lumley; E. A. Terray

1983-11-01T23:59:59.000Z

277

Wind Power Forecasting  

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

Retrospective Reports 2011 Smart Grid Wind Integration Wind Integration Initiatives Wind Power Forecasting Wind Projects Email List Self Supplied Balancing Reserves Dynamic...

278

Interfaces and inhomogeneous turbulence  

Science Journals Connector (OSTI)

...argued that these local distortion mechanisms...meteorological model WRF [58]. This is...anabatic and katabatic winds. The thermal forcing...wind, the cross-wind horizontal breeze...This leads to a local vortex form with...the length of the wind tunnel where the...10], using the local RMS velocity and...

2011-01-01T23:59:59.000Z

279

Real time grid congestion management in presence of high penetration of wind energy  

E-Print Network [OSTI]

Real time grid congestion management in presence of high penetration of wind energy A. Vergnol1 , J », « Wind energy », « Variable speed drive » Abstract With the increased use of wind energy the power

Boyer, Edmond

280

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

Note: This page contains sample records for the topic "turbulence wind variability" 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

Feasibility analysis of coordinated offshore wind project development in the U.S.  

E-Print Network [OSTI]

Wind energy is one of the cleanest and most available resources in the world, and advancements in wind technology are making it more cost effective. Though wind power is rapidly developing in many regions, its variable ...

Zhang, Mimi Q

2008-01-01T23:59:59.000Z

282

Wind turbine  

SciTech Connect (OSTI)

The improvement in a wind turbine comprises providing a tower with a freely liftable mount and adapting a nacelle which is fitted with a propeller windwheel consisting of a plurality of rotor blades and provided therein with means for conversion of wind energy to be shifted onto said mount attached to the tower. In case of a violent wind storm, the nacelle can be lowered down to the ground to protect the rotor blades from breakage due to the force of the wind. Required maintenance and inspection of the nacelle and replacement of rotor blades can be safely carried out on the ground.

Abe, M.

1982-01-19T23:59:59.000Z

283

NREL: Energy Analysis - Wind Technology Analysis  

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

Wind and Hydropower Technology Analysis Wind and Hydropower Technology Analysis Wind and hydropower analysis supports advanced technologies that convert more of the nation's wind into electricity. Grid Operational Impact Analysis The wind program will address the variable, normally uncontrollable nature of wind power plant output, and the additional needs that its operation imposes on the overall grid. At present, the generation and transmission operational impacts that occur due to wind variability are not well quantified. This research will include efforts to quantify and fairly allocate impacts in both an engineering and cost sense. Methods of analysis are at an early stage of development. Without realistic analysis and cost allocation, utilities tend to overestimate imposed operational costs,

284

Alfven wave collisions, the fundamental building block of plasma turbulence. IV. Laboratory experiment  

E-Print Network [OSTI]

of the interstellar medium,1 acceleration of the solar wind,2,3 solar coronal heating,4 trans- port of energy and mass, Valdosta, Georgia 31698, USA 2 Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa heating, acceleration of the solar wind, and heating of the interstellar medium. Turbulence

California at Los Angles, University of

285

Performance of twist-coupled blades on variable speed rotors  

SciTech Connect (OSTI)

The load mitigation and energy capture characteristics of twist-coupled HAWT blades that are mounted on a variable speed rotor are investigated in this paper. These blades are designed to twist toward feather as they bend with pretwist set to achieve a desirable twist distribution at rated power. For this investigation, the ADAMS-WT software has been modified to include blade models with bending-twist coupling. Using twist-coupled and uncoupled models, the ADAMS software is exercised for steady wind environments to generate C{sub p} curves at a number of operating speeds to compare the efficiencies of the two models. The ADAMS software is also used to generate the response of a twist-coupled variable speed rotor to a spectrum of stochastic wind time series. This spectrum contains time series with two mean wind speeds at two turbulence levels. Power control is achieved by imposing a reactive torque on the low speed shaft proportional to the RPM squared with the coefficient specified so that the rotor operates at peak efficiency in the linear aerodynamic range, and by limiting the maximum RPM to take advantage of the stall controlled nature of the rotor. Fatigue calculations are done for the generated load histories using a range of material exponents that represent materials from welded steel to aluminum to composites, and results are compared with the damage computed for the rotor without twist-coupling. Results indicate that significant reductions in damage are achieved across the spectrum of applied wind loading without any degradation in power production.

Lobitz, D.W.; Veers, P.S.; Laino, D.J.

1999-12-07T23:59:59.000Z

286

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

287

Wind Powering America: Wind Events  

Wind Powering America (EERE)

calendar.asp Lists upcoming wind calendar.asp Lists upcoming wind power-related events. en-us julie.jones@nrel.gov (Julie Jones) http://www.windpoweringamerica.gov/images/wpa_logo_sm.jpg Wind Powering America: Wind Events http://www.windpoweringamerica.gov/calendar.asp Pennsylvania Wind for Schools Educator Workshop https://www.regonline.com/builder/site/Default.aspx?EventID=1352684 http://www.windpoweringamerica.gov/filter_detail.asp?itemid=4068 Wed, 4 Dec 2013 00:00:00 MST 2014 Joint Action Workshop http://www.windpoweringamerica.gov/filter_detail.asp?itemid=3996 http://www.windpoweringamerica.gov/filter_detail.asp?itemid=3996 Mon, 21 Oct 2013 00:00:00 MST AWEA Wind Project Operations and Maintenance and Safety Seminar http://www.windpoweringamerica.gov/filter_detail.asp?itemid=4009 http://www.windpoweringamerica.gov/filter_detail.asp?itemid=4009 Mon, 21

288

Active power regulation of wind power systems through demand response  

Science Journals Connector (OSTI)

With the specific characteristics of low-carbon intensity and economy, wind power has been widely promoted around the world. Due to the variable and intermittent nature of wind power production, the system has to...

WeiWei Miao; HongJie Jia; Dan Wang; Simon Parkinson…

2012-06-01T23:59:59.000Z

289

A simulation-based planning system for wind turbine construction  

Science Journals Connector (OSTI)

Wind turbine construction is a challenging undertaking due to the need to lift heavy loads to high locations in conditions of high and variable wind speeds. These conditions create great risks to contractors during the turbine assembly process. This ...

Dina Atef; Hesham Osman; Moheeb Ibrahim; Khaled Nassar

2010-12-01T23:59:59.000Z

290

NREL: Wind Research - Abundant Renewable Energy's ARE 442 Wind Turbine  

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

Abundant Renewable Energy's ARE 442 Wind Turbine Testing and Results Abundant Renewable Energy's ARE 442 Wind Turbine Testing and Results Get the Adobe Flash Player to see this video. A video of Abundant Renewable Energy's ARE 442 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 Abundant Renewable Energy's ARE 442 turbine at the National Wind Technology Center (NWTC). The ARE 442 is a 10-kilowatt (kW), three-bladed, horizontal-axis upwind small wind turbine. It has a hub height of 30.9 meters and a rotor diameter of 7.2 meters. The turbine has a single-phase permanent-magnet generator that operates at variable voltages up to 410 volts AC. Testing Summary The summary of the tests is below with the final reports.

291

Turbulence avoidance: An alternate explanation of turbulence ...  

Science Journals Connector (OSTI)

ABSTRACT: Field observations supporting the hypothesis that wind-driven ... tend not to have the resolving power to distinguish an alternative hypothesis: that

292

Modelling suspended sediment in environmental turbulent fluids  

E-Print Network [OSTI]

Modelling sediment transport in environmental turbulent fluids is a challenge. This article develops a sound model of the lateral transport of suspended sediment in environmental fluid flows such as floods and tsunamis. The model is systematically derived from a 3D turbulence model based on the Smagorinski large eddy closure. Embedding the physical dynamics into a family of problems and analysing linear dynamics of the system, centre manifold theory indicates the existence of slow manifold parametrised by macroscale variables. Computer algebra then constructs the slow manifold in terms of fluid depth, depth-averaged lateral velocities, and suspended sediment concentration. The model includes the effects of sediment erosion, advection, dispersion, and also the interactions between the sediment and turbulent fluid flow. Vertical distributions of the velocity and concentration in steady flow agree with the established experimental data. Numerical simulations of the suspended sediment under large waves show that ...

Cao, Meng

2014-01-01T23:59:59.000Z

293

OBSERVATION OF FLUX-TUBE CROSSINGS IN THE SOLAR WIND  

SciTech Connect (OSTI)

Current sheets are ubiquitous in the solar wind. They are a major source of the solar wind MHD turbulence intermittency. They may result from nonlinear interactions of the solar wind MHD turbulence or are the boundaries of flux tubes that originate from the solar surface. Some current sheets appear in pairs and are the boundaries of transient structures such as magnetic holes and reconnection exhausts or the edges of pulsed Alfven waves. For an individual current sheet, discerning whether it is a flux-tube boundary or due to nonlinear interactions or the boundary of a transient structure is difficult. In this work, using data from the Wind spacecraft, we identify two three-current-sheet events. Detailed examination of these two events suggests that they are best explained by the flux-tube-crossing scenario. Our study provides convincing evidence supporting the scenario that the solar wind consists of flux tubes where distinct plasmas reside.

Arnold, L.; Li, G.; Li, X. [Department of Physics and CSPAR, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)] [Department of Physics and CSPAR, University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Yan, Y., E-mail: gang.li@uah.edu [Key Laboratory of Solar Activity, National Astronomical Observatories of Chinese Academy of Sciences, Beijing 100012 (China)

2013-03-20T23:59:59.000Z

294

Research on Control System of High Power DFIG Wind Power System  

Science Journals Connector (OSTI)

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

Li Jianlin; Xu Honghua

2008-12-01T23:59:59.000Z

295

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

296

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

Science Journals Connector (OSTI)

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

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

2010-05-01T23:59:59.000Z

297

Wyoming Wind Power Project (generation/wind)  

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

Wind Power > Generation Hydro Power Wind Power Monthly GSP BPA White Book Dry Year Tools Firstgov Wyoming Wind Power Project (Foote Creek Rim I and II) Thumbnail image of wind...

298

Offshore Wind Power USA  

Broader source: Energy.gov [DOE]

The Offshore Wind Power USA conference provides the latest offshore wind market updates and forecasts.

299

Argonne National Laboratory Develops Extreme-Scale Wind Farm Simulation Capabilities  

Broader source: Energy.gov [DOE]

Researchers at DOE's Argonne National Laboratory are developing a computational simulation tool to conduct studies of complex flow and wind turbine interactions in large land-based and offshore wind farms that will improve wind plant design and reduce the levelized cost of energy. Simulations on a wind-plant-scale require accurate simultaneous resolution of multiple flow scales, from mesoscale weather to turbine-blade scale turbulence, which presents special demands on the computational solver efficiency and requires extreme scalability.

300

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

Note: This page contains sample records for the topic "turbulence wind variability" 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

Impact of DFIG wind turbines on transient stability of power systems a review  

E-Print Network [OSTI]

Impact of DFIG wind turbines on transient stability of power systems ­ a review Authors Na Abstract of wind farms are using variable speed wind turbines equipped with doubly-fed induction generators (DFIG) due to their advantages over other wind turbine generators. Therefore, the analysis of wind power

Pota, Himanshu Roy

302

A Minnesota Blizzard Provides Insight into Utility-Scale Wind Turbine Wakes  

Broader source: Energy.gov [DOE]

Starting in 2012, researchers tried placing spotlights downwind from the 2.5-megawatt (MW) wind turbine in Rosemount, Minnesota. The research team was attempting to study turbulent airflow around a turbine in the field.

303

Near-surface wind estimates using statistics from a planetary boundary-layer model  

Science Journals Connector (OSTI)

This paper shows the possibilities of a procedure for estimating near-surface wind statistics, by means of the numerical integration of a simple boundary-layer model with a second-order turbulent closure. Stan...

J. C. Labraga

1988-04-01T23:59:59.000Z

304

offshore wind farm  

Science Journals Connector (OSTI)

offshore wind farm, wind farm [‘Wind park’ which one may find on the ... engineers and should not be used. A wind farm consists of a network of wind turbines] ? Windkraftanlage f, Windpark m; Offshore

2014-08-01T23:59:59.000Z

305

Wind Energy Leasing Handbook  

E-Print Network [OSTI]

Wind Energy Leasing Handbook Wind Energy Leasing Handbook E-1033 Oklahoma Cooperative Extension?..................................................................................................................... 31 What do wind developers consider in locating wind energy projects?............................................................................................ 37 How do companies and individuals invest in wind energy projects?....................................................................

Balasundaram, Balabhaskar "Baski"

306

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

307

4A.5 DERIVING TURBULENT KINETIC ENERGY DISSIPATION RATE WITHIN CLOUDS USING GROUND BASED 94 GHZ RADAR  

E-Print Network [OSTI]

distribution of the optical and microphysics properties. Turbulence is also directly linked to the life cycle is to perform spectral analysis on air- craft data (for instance Gultepe and Starr (1995)) or from ground based. The variance 1 #12;v 2 of the mean wind is an indicator of the kinetic energy in turbulent scales

Hogan, Robin

308

Aerodynamic Thrust Modelling in Wave Tank Tests of Offshore Floating Wind Turbines Using a Ducted Fan  

Science Journals Connector (OSTI)

Wave tank testing of scaled models is standard practice during the development of floating wind turbine platforms for the validation of the dynamics of conceptual designs. Reliable recreation of the dynamics of a full scale floating wind turbine by a scaled model in a basin requires the precise scaling of the masses and inertias and also the relevant forces and its frequencies acting on the system. The scaling of floating wind turbines based on the Froude number is customary for basin experiments. This method preserves the hydrodynamic similitude, but the resulting Reynolds number is much lower than in full scale. The aerodynamic loads on the rotor are therefore out of scale. Several approaches have been taken to deal with this issue, like using a tuned drag disk or redesigning the scaled rotor. This paper describes the implementation of an alternative method based on the use of a ducted fan located at the model tower top in the place of the rotor. The fan can introduce a variable force that represents the total wind thrust by the rotor. A system controls this force by varying the rpm, and a computer simulation of the full scale rotor provides the desired thrust to be introduced by the fan. This simulation considers the wind turbine control, gusts, turbulent wind, etc. The simulation is performed in synchronicity with the test and it is fed in real time by the displacements and velocities of the platform captured by the acquisition system. Thus, the simulation considers the displacements of the rotor within the wind field and the calculated thrust models the effect of the aerodynamic damping. The system is not able currently to match the effect of gyroscopic momentum. The method has been applied during a test campaign of a semisubmersible platform with full catenary mooring lines for a 6MW wind turbine in scale 1/40 at Ecole Centrale de Nantes. Several tests including pitch free decay under constant wind and combined wave and wind cases have been performed. Data from the experiments are compared with aero-servo-hydro-elastic computations with good agreement showing the validity of the method for the representation of the scaled aerodynamics. The new method for the aerodynamic thrust scaling in basin tests is very promising considering its performance, versatility and lower cost in comparison with other methods.

José Azcona; Faisal Bouchotrouch; Marta González; Joseba Garciandía; Xabier Munduate; Felix Kelberlau; Tor A Nygaard

2014-01-01T23:59:59.000Z

309

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

310

Wind Powering America: New England Wind Forum  

Wind Powering America (EERE)

About the New England Wind Forum About the New England Wind Forum New England Wind Energy Education Project Historic Wind Development in New England State Activities Projects in New England Building Wind Energy in New England Wind Resource Wind Power Technology Economics 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 The New England Wind Forum was conceived in 2005 as a platform to provide a single, comprehensive and objective source of up-to-date, Web-based information on a broad array of wind-energy-related issues pertaining to New England. The New England Wind Forum provides information to wind energy stakeholders through Web site features, periodic newsletters, and outreach activities. The New England Wind Forum covers the most frequently discussed wind energy topics.

311

Predicting aerodynamic characteristic of typical wind turbine airfoils using CFD  

SciTech Connect (OSTI)

An investigation was conducted into the capabilities and accuracy of a representative computational fluid dynamics code to predict the flow field and aerodynamic characteristics of typical wind-turbine airfoils. Comparisons of the computed pressure and aerodynamic coefficients were made with wind tunnel data. This work highlights two areas in CFD that require further investigation and development in order to enable accurate numerical simulations of flow about current generation wind-turbine airfoils: transition prediction and turbulence modeling. The results show that the laminar-to turbulent transition point must be modeled correctly to get accurate simulations for attached flow. Calculations also show that the standard turbulence model used in most commercial CFD codes, the k-e model, is not appropriate at angles of attack with flow separation. 14 refs., 28 figs., 4 tabs.

Wolfe, W.P. [Sandia National Labs., Albuquerque, NM (United States); Ochs, S.S. [Iowa State Univ., Ames, IA (United States). Aerospace Engineering Dept.

1997-09-01T23:59:59.000Z

312

Wind News  

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

news Office of Energy Efficiency & Renewable news Office of Energy Efficiency & Renewable Energy Forrestal Building 1000 Independence Avenue, SW Washington, DC 20585 en New Report Shows Trend Toward Larger Offshore Wind Systems, with 11 Advanced Stage Projects Proposed in U.S. Waters http://energy.gov/eere/articles/new-report-shows-trend-toward-larger-offshore-wind-systems-11-advanced-stage-projects wind-systems-11-advanced-stage-projects" class="title-link">New Report Shows Trend Toward Larger Offshore Wind Systems, with 11 Advanced Stage Projects Proposed in U.S. Waters

313

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

314

PERPENDICULAR ION HEATING BY REDUCED MAGNETOHYDRODYNAMIC TURBULENCE  

SciTech Connect (OSTI)

Recent theoretical studies argue that the rate of stochastic ion heating in low-frequency Alfvén-wave turbulence is given by Q = c{sub 1}((?u){sup 3}/?)exp (– c{sub 2}/?), where ?u is the rms turbulent velocity at the scale of the ion gyroradius ?, ? = ?u/v{sub i}, v{sub i} is the perpendicular ion thermal speed, and c{sub 1} and c{sub 2} are dimensionless constants. We test this theoretical result by numerically simulating test particles interacting with strong reduced magnetohydrodynamic (RMHD) turbulence. The heating rates in our simulations are well fit by this formula. The best-fit values of c{sub 1} are ?1. The best-fit values of c{sub 2} decrease (i.e., stochastic heating becomes more effective) as the Reynolds number and the number of grid points in the RMHD simulations increase. As an example, in a 1024{sup 2} × 256 RMHD simulation with a dissipation wavenumber of the order of the inverse ion gyroradius, we find c{sub 2} = 0.21. We show that stochastic heating is significantly stronger in strong RMHD turbulence than in a field of randomly phased Alfvén waves with the same power spectrum, because coherent structures in strong RMHD turbulence increase orbit stochasticity in the regions where ions are heated most strongly. We find that c{sub 1} increases by a factor of ?3 while c{sub 2} changes very little as the ion thermal speed increases from values <wind.

Xia, Qian; Perez, Jean C.; Chandran, Benjamin D. G. [Space Science Center and Department of Physics, University of New Hampshire, Durham, NH (United States); Quataert, Eliot, E-mail: qdy2@unh.edu, E-mail: benjamin.chandran@unh.edu, E-mail: jeanc.perez@unh.edu, E-mail: eliot@astro.berkeley.edu [Astronomy Department and Theoretical Astrophysics Center, 601 Campbell Hall, The University of California, Berkeley, CA 94720 (United States)

2013-10-20T23:59:59.000Z

315

Wind Energy Benefits, Wind Powering America (WPA) (Fact Sheet...  

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

Energy Benefits, Wind Powering America (WPA) (Fact Sheet), Wind And Water Power Program (WWPP) Wind Energy Benefits, Wind Powering America (WPA) (Fact Sheet), Wind And Water Power...

316

NREL: Wind Research - Research Staff Biographies  

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

and Eduard Muljadi on a soon-to-be-published history of Variable-Speed Operation of Wind Turbines. Photo of Corrie Christol Corrie Christol Administrative Project Manager, National...

317

Vertical Axis Wind Turbine Foundation parameter study  

SciTech Connect (OSTI)

The dynamic failure criterion governing the dimensions of prototype Vertical Axis Wind Turbine Foundations is treated as a variable parameter. The resulting change in foundation dimensions and costs is examined.

Lodde, P.F.

1980-07-01T23:59:59.000Z

318

Wind and Solar Energy Curtailment Practices (Presentation)  

SciTech Connect (OSTI)

This presentation to the fall 2014 technical meeting of the Utility Variable-Generation Integration Group summarizes experience with curtailment of wind and solar in the U.S.

Bird, L.; Cochran, J.; Wang, X.

2014-10-01T23:59:59.000Z

319

Energy Analysis of Convectively Induced Wind Perturbations  

Science Journals Connector (OSTI)

Budgets of divergent and rotational components of kinetic energy (KD and KR) are examined for four upper level wind speed maxima that develop during the fourth Atmospheric Variability Experiment (AVE IV) and the first AVE-Severe Environmental ...

Henry E. Fuelberg; Dennis E. Buechler

1989-04-01T23:59:59.000Z

320

Large-eddy simulation of offshore wind farm  

Science Journals Connector (OSTI)

A hybrid numerical capability is developed for the simulation of offshore wind farms in which large-eddy simulation is performed for the wind turbulence and a potential flow based method is used for the simulation of the ocean wave field. The wind and wave simulations are dynamically coupled. The effect of wind turbines on the wind field is represented by an actuator disk model. This study focuses on the effect of wind-seas and the turbine motion is treated as negligibly small. A variety of fully-developed and fetch-limited wind-sea conditions and turbine spacings are considered in the study. Statistical analyses are performed for the simulation results with a focus on the mean wind profile kinetic energy budget in the wind field and the wind turbine power extraction rate. The results indicate that the waves have appreciable effect on the wind farm performance. The wind turbines obtain a higher wind power extraction rate under the fully developed wind-sea condition compared with that under the fetch-limited condition. This higher extraction rate is caused by the faster propagating waves and the lower sea-surface resistance on the wind when the wind-seas are fully developed. The wave-induced difference can be as high as 8% with the commonly used turbine spacing in commercial land-based wind farms s x = 7 (with s x being the ratio of streamwise turbine spacing to the turbine diameter). Such level of difference is noteworthy considering the previous understanding that direct wave-induced disturbance to the wind field decays exponentially away from wave surface.

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "turbulence wind variability" 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

Observations of Edge Turbulence  

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

Edge Turbulence Edge Turbulence near the X-point of Alcator C-Mod APS-2007 (1) J.L. Terry, S.J. Zweben*, B. LaBombard, I. Cziegler, O. Grulke + , D.P. Stotler* MIT - Plasma Science and Fusion Center *Princeton Plasma Physics Laboratory + MPI for Plasma Physics, EURATOM Assoc., Greifswald, Germany American Physical Society - Div. of Plasma Physics Orlando, FL Nov. 12 - Nov. 16, 2007 APS-2007 (2) Background and Motivation for "Xpt-region" View Strong edge turbulence has been observed in nearly all magnetic confinement devices. Desire predictive capability Most previous measurements made near outboard midplane where the turbulence has the following main features: - generation is ballooning-like (absent at inboard midplane, etc.) - filaments/blobs moves radially outward with some poloidal motion

322

ARM - Measurement - Atmospheric turbulence  

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

turbulence turbulence 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 : Atmospheric turbulence High frequency velocity fluctuations that lead to turbulent transport of momentum, heat, mositure, and passive scalars, and often expressed in terms of variances and covariances. Categories Atmospheric State, Surface Properties 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 CO2FLX : Carbon Dioxide Flux Measurement Systems ECOR : Eddy Correlation Flux Measurement System

323

Information Content of Turbulence  

E-Print Network [OSTI]

We treat a turbulent velocity field as a message in the same way as a book or a picture. All messages can be described by their entropy per symbol $h$, defined as in Shannon's theory of communication. In a turbulent flow, as the Reynolds number $Re$ increases, more correlated degrees of freedom are excited and participate in the turbulent cascade. Experiments in a turbulent soap film suggest that the spatial entropy density $h$ is a decreasing function of $Re$, namely $h \\propto -\\log Re$ + const. In the logistic map, also analyzed here, increasing the control parameter $r$ increases $h$. A modified logistic map with additional coupling to past iterations suggests the significance of correlations.

Rory Cerbus; Walter Goldburg

2013-07-03T23:59:59.000Z

324

Study of Stability Analysis of a Grid-Connected Doubly Fed Induction Generator (DFIG)-based small Wind Farm.  

E-Print Network [OSTI]

??Wind is the most reliable, clean and fast-developing renewable energy source. The DFIG-based variable speed wind turbine system is now the most popular in wind… (more)

Dhar, Baishakhi

2013-01-01T23:59:59.000Z

325

NREL: Wind Research - Wind Resource Assessment  

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

Wind Resource Assessment Wind Resource Assessment A map of the United States is color-coded to indicate the high winds at 80 meters. This map shows the wind resource at 80 meters for both land-based and offshore wind resources in the United States. Correct estimation of the energy available in the wind can make or break the economics of wind plant development. Wind mapping and validation techniques developed at the National Wind Technology Center (NWTC) along with collaborations with U.S. companies have produced high-resolution maps of the United States that provide wind plant developers with accurate estimates of the wind resource potential. State Wind Maps International Wind Resource Maps Dynamic Maps, GIS Data, and Analysis Tools Due to the existence of special use airspace (SUA) (i.e., military airspace

326

New England Wind Forum: Wind Power Technology  

Wind Powering America (EERE)

Wind Power Technology Wind Power Technology Modern wind turbines have become sophisticated power plants while the concept of converting wind energy to electrical energy remains quite simple. Follow these links to learn more about the science behind wind turbine technology. Wind Power Animation An image of a scene from the wind power animation. The animation shows how moving air rotates a wind turbine's blades and describes how the internal components work to produce electricity. It shows small and large wind turbines and the differences between how they are used, as stand alone or connected to the utility grid. How Wind Turbines Work Learn how wind turbines make electricity; what are the types, sizes, and applications of wind turbines; and see an illustration of the components inside a wind turbine.

327

2011 Wind Technologies Market Report  

E-Print Network [OSTI]

that includes wind turbine towers. 2011 Wind TechnologiesSets Other Wind Turbine Components Towers Wind-Poweredselected wind turbine components includes towers as well as

Bolinger, Mark

2013-01-01T23:59:59.000Z

328

2010 Wind Technologies Market Report  

E-Print Network [OSTI]

that includes wind turbine towers. 2010 Wind TechnologiesImports : Other Wind Turbine Components Towers Wind-Poweredselected wind turbine components includes towers as well as

Wiser, Ryan

2012-01-01T23:59:59.000Z

329

Energy 101: Wind Turbines  

ScienceCinema (OSTI)

See how wind turbines generate clean electricity from the power of the wind. Highlighted are the various parts and mechanisms of a modern wind turbine.

None

2013-05-29T23:59:59.000Z

330

Balancing of Wind Power.  

E-Print Network [OSTI]

?? In the future, renewable energy share, especially wind power share, in electricity generation is expected to increase. Due to nature of the wind, wind… (more)

Ülker, Muhammed Akif

2011-01-01T23:59:59.000Z

331

Energy 101: Wind Turbines  

SciTech Connect (OSTI)

See how wind turbines generate clean electricity from the power of the wind. Highlighted are the various parts and mechanisms of a modern wind turbine.

None

2011-01-01T23:59:59.000Z

332

WINDExchange: Learn About Wind  

Wind Powering America (EERE)

Curricula & Teaching Materials Resources Learn About Wind Learn about how wind energy generates power; where the best wind resources are; how you can own, host, partner...

333

Wind power and Wind power and  

E-Print Network [OSTI]

Wind power and the CDM #12; Wind power and the CDM Emerging practices in developing wind power 2005 Jyoti P. Painuly, Niels-Erik Clausen, Jørgen Fenhann, Sami Kamel and Romeo Pacudan #12; WIND POWER AND THE CDM Emerging practices in developing wind power projects for the Clean Development Mechanism Energy

334

Wind modelling based on wind input data conditions using Weibull distribution  

Science Journals Connector (OSTI)

Weibull distribution can be used to model the wind speed distribution at a particular site and hence, it can help in wind resource assessment (WRA) of a site. By calculating the shape (k) and scale (c) parameters for Weibull distribution, the wind speed frequency curve for a site can be made. Once this wind speed distribution for site is determined, it can be convolved with the power curve for a wind turbine and the annual energy output from the site can be determined. This paper presents how the Weibull distribution is used to determine the wind speed distribution for Vadravadra site in Gau Island of Fiji and how closely the annual energy output from the modelled wind speed distribution matches with the annual energy output using the actual wind speed distribution. It also presents how k is related to the turbulence intensity for a site; how the c is related to the annual mean wind speed and how a formula for estimating c is derived at a new height.

R.D. Prasad; R.C. Bansal; M. Sauturaga

2009-01-01T23:59:59.000Z

335

Validation of Power Output for the WIND Toolkit  

SciTech Connect (OSTI)

Renewable energy integration studies require wind data sets of high quality with realistic representations of the variability, ramping characteristics, and forecast performance for current wind power plants. The Wind Integration National Data Set (WIND) Toolkit is meant to be an update for and expansion of the original data sets created for the weather years from 2004 through 2006 during the Western Wind and Solar Integration Study and the Eastern Wind Integration Study. The WIND Toolkit expands these data sets to include the entire continental United States, increasing the total number of sites represented, and it includes the weather years from 2007 through 2012. In addition, the WIND Toolkit has a finer resolution for both the temporal and geographic dimensions. Three separate data sets will be created: a meteorological data set, a wind power data set, and a forecast data set. This report describes the validation of the wind power data set.

King, J.; Clifton, A.; Hodge, B. M.

2014-09-01T23:59:59.000Z

336

Optimal Bidding Strategies for Wind Power Producers with Meteorological Forecasts  

E-Print Network [OSTI]

Optimal Bidding Strategies for Wind Power Producers with Meteorological Forecasts Antonio that the inherent variability in wind power generation and the related difficulty in predicting future generation profiles, raise major challenges to wind power integration into the electricity grid. In this work we study

Giannitrapani, Antonello

337

Maximum power tracking control scheme for wind generator systems  

E-Print Network [OSTI]

The purpose of this work is to develop a maximum power tracking control strategy for variable speed wind turbine systems. Modern wind turbine control systems are slow, and they depend on the design parameters of the turbine and use wind and/or rotor...

Mena, Hugo Eduardo

2009-05-15T23:59:59.000Z

338

Maximum power tracking control scheme for wind generator systems  

E-Print Network [OSTI]

The purpose of this work is to develop a maximum power tracking control strategy for variable speed wind turbine systems. Modern wind turbine control systems are slow, and they depend on the design parameters of the turbine and use wind and/or rotor...

Mena Lopez, Hugo Eduardo

2008-10-10T23:59:59.000Z

339

Control of Wind Turbines for Power Regulation and  

E-Print Network [OSTI]

Control of Wind Turbines for Power Regulation and Load Reduction Juan Jose Garcia Quirante Kongens regulation and load reduction and their ensemble in a variable-speed wind turbine. The power regulation aspects of mathematical modelling of wind turbines, and especially the control methods suited for power

340

Solar wind and the motion of dust grains  

Science Journals Connector (OSTI)

......we concentrated on the action of the solar wind on the motion of an IDP for cases when the variable flux of the solar wind energy and the non-radial solar wind velocity are considered. Particle erosion does not have a large influence on the......

J. Klacka; J. Petrzala; P. Pástor; L. Kómar

2012-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "turbulence wind variability" 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 WAVENUMBER SPECTRA OF SCATTEROMETER-DERIVED WINDS  

E-Print Network [OSTI]

to slightly different power law predictions for the wind spectrum. Freilich and Chelton [l]first used Seasat at the ocean's surface. Such measurements are critical inputs in studies of oceanic circulation and air/seainteraction where the time variability of the surface wind field and the wind stress curl drive the ocean; hence

Long, David G.

342

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.

343

New England Wind Forum: Large Wind  

Wind Powering America (EERE)

Small Wind Small Wind Large Wind Newsletter Perspectives Events Quick Links to States CT MA ME NH RI VT Bookmark and Share Large Wind When establishing wind farms, wind energy developers generally approach landowners where they want to build. Interest in wind farms is frequently spurred by external pressures such as tax and other financial incentives and legislative mandates. Since each situation is influenced by local policies and permitting, we can only provide general guidance to help you learn about the process of installing wind turbines. Publications Wind Project Development Process Permitting of Wind Energy Facilities: A Handbook. (August 2002). National Wind Coordinating Collaborative. Landowner Frequently Asked Questions and Answers. (August 2003). "State Wind Working Group Handbook." pp. 130-133.

344

NREL: Wind Research - International Wind Resource Maps  

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

projections of wind resources worldwide. This allows for more accurate siting of wind turbines and has led to the recognition of higher class winds in areas where none were...

345

Center for Turbulence Research Proceedings of the Summer Program 2012  

E-Print Network [OSTI]

for windmill airfoil design under variable wind conditions By H. Tachikawa, D. Schiavazzi, T. Arima AND G-1093 Japan Department of Mathematics, University of Padua, Italy #12;242 Tachikawa et al. Rotational

Wang, Wei

346

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.

347

Advanced Hydraulic Wind Energy  

Science Journals Connector (OSTI)

The Jet Propulsion Laboratory, California Institute of Technology, has developed a novel advanced hydraulic wind energy design, which has up to 23% performance improvement over conventional wind turbine and conventional hydraulic wind energy systems ... Keywords: wind, tide, energy, power, hydraulic

Jack A. Jones; Allan Bruce; Adrienne S. Lam

2013-04-01T23:59:59.000Z

348

WINDExchange: Wind Economic Development  

Wind Powering America (EERE)

help you analyze the economics of a small wind electric system and decide whether wind energy will work for you. Wind Energy Finance Online Calculator Wind Energy Finance developed...

349

Exploiting Wind Versus Coal  

Science Journals Connector (OSTI)

...be offset with turbine mass production...of installed turbines, more than the...Denmark have wind parks offshore, where winds...of installed turbines, more than the...Denmark have wind parks offshore, where winds...

Mark Z. Jacobson; Gilbert M. Masters

2001-08-24T23:59:59.000Z

350

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

351

National Offshore Wind Energy Grid Interconnection Study  

SciTech Connect (OSTI)

The National Offshore Wind Energy Grid Interconnection Study (NOWEGIS) considers the availability and potential impacts of interconnecting large amounts of offshore wind energy into the transmission system of the lower 48 contiguous United States. A total of 54GW of offshore wind was assumed to be the target for the analyses conducted. A variety of issues are considered including: the anticipated staging of offshore wind; the offshore wind resource availability; offshore wind energy power production profiles; offshore wind variability; present and potential technologies for collection and delivery of offshore wind energy to the onshore grid; potential impacts to existing utility systems most likely to receive large amounts of offshore wind; and regulatory influences on offshore wind development. The technologies considered the reliability of various high-voltage ac (HVAC) and high-voltage dc (HVDC) technology options and configurations. The utility system impacts of GW-scale integration of offshore wind are considered from an operational steady-state perspective and from a regional and national production cost perspective.

Daniel, John P. [ABB Inc; Liu, Shu [ABB Inc; Ibanez, Eduardo [National Renewable Energy Laboratory; Pennock, Ken [AWS Truepower; Reed, Greg [University of Pittsburgh; Hanes, Spencer [Duke Energy

2014-07-30T23:59:59.000Z

352

NREL: Wind Research - Wind Energy Videos  

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

Wind Energy Videos The National Wind Technology Center (NWTC) is pleased to offer video presentations of its world-class capabilities, facilities, research areas, and personnel. As...

353

On the Degeneration of Turbulence at High Reynolds Numbers  

E-Print Network [OSTI]

Turbulent fluctuations in a fluid wind down at a certain rate once stirring has stopped. The role of the most basic parameter in fluid mechanics, the Reynolds number, in setting this decay rate is not generally known. This paper concerns the high-Reynolds-number limit of the process. In a wind-tunnel experiment that reached higher Reynolds numbers than ever before and covered more than two decades in the Reynolds number ($10^4 speed of the flow, $M$ the forcing scale, and $\

Sinhuber, Michael; Bewley, Gregory P

2014-01-01T23:59:59.000Z

354

wind power station  

Science Journals Connector (OSTI)

wind power station [It may consist of just one wind turbine or a network of windmills] ? Windkraftanlage

2014-08-01T23:59:59.000Z

355

Assessment of research needs for wind turbine rotor materials technology  

SciTech Connect (OSTI)

Wind-driven power systems is a renewable energy technology that is still in the early stages of development. Wind power plants installed in early 1980s suffered structural failures chiefly because of incomplete understanding of wind forces (turbulent), in some cases because of poor product quality. Failures of rotor blades are now somewhat better understood. This committee has examined the experience base accumulated by wind turbines and the R and D programs sponsored by DOE. It is concluded that a wind energy system such as is described is within the capability of engineering practice; however because of certain gaps in knowledge, and the presence of only one major integrated manufacturer of wind power machines in the USA, a DOE R and D investment is still required.

Not Available

1991-01-01T23:59:59.000Z

356

Turbulence Structure and Wall Signature in Hypersonic Turbulent Boundary Layer  

E-Print Network [OSTI]

Turbulence Structure and Wall Signature in Hypersonic Turbulent Boundary Layer Yin-Chiu Kan , Clara and hypersonic turbulent boundary layer datasets from direct numerical simulation (DNS). Contour plots and Marusic5 and Mathis, Hutchins and Marusic16 ). In contrast to supersonic and hypersonic flow regimes

Martín, Pino

357

Experimental study of vortex generators effects on low Reynolds number airfoils in turbulent flow  

Science Journals Connector (OSTI)

In the present work, we study the aerodynamic effects of triangular vortex generators, as passive flow control devices, placed on the upper surface of an airfoil submitted to a low Reynolds number turbulent flow. In the experiments, different configurations of those devices have been studied. An Eppler 387 airfoil was used. The tests were performed in a turbulent boundary layer wind tunnel using a two component aerodynamic balance and flow visualisation systems. Turbulent flow characterisation was made by means of hot wire anemometry. Calculations of local turbulent intensity as well as temporal and spatial turbulent scales were made. Vortex generators were located at 10% and 20% of the airfoil chord from the leading edge, modifying its angle of incidence refereed to the free stream. The results show changes in the aerodynamic section coefficients, C1, Cd and C1, for the different vortex generator configurations. Neither hysteresis effects, nor leading edge bubbles were found in the experiments.

Juan Sebastián Delnero; Julio Marañon Di Leo; Mauricio Ezequiel Camocardi; Mariano A. Martinez; Jorge L. Colman Lerner

2012-01-01T23:59:59.000Z

358

NREL: Wind Research - Small Wind Turbine Webinars  

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

Small Wind Turbine Webinars Small Wind Turbine Webinars Here you will find webinars about small wind turbines that NREL hosted. Introducing WindLease(tm): Making Wind Energy Affordable NREL and the American Solar Energy Society (ASES) Wind Division co-hosted this webinar. (Text Version.) Date: August 1, 2013 Run Time: 40 minutes Joe Hess, VP of Business Development at United Wind, described United Wind's WindQuote and WindLease Program and explained the process from the dealer's and consumer's perspective. Texas Renewable Energy Industries Association NREL and the American Solar Energy Society (ASES) Wind Division co-hosted this webinar. (Text Version). Date: March 7, 2013 Run Time: 1 hour Russel Smith, Texas Renewable Energy Industries Association executive director and co-founder, provided an overview of the trade association

359

New England Wind Forum: Small Wind  

Wind Powering America (EERE)

Wind for Schools Project Funding Case Studies: Thomas Harrison Middle School, Virginia Wind for Schools Project Funding Case Studies: Thomas Harrison Middle School, Virginia August 26, 2013 Workshop Explores Information's Role in Wind Project Siting: A Wind Powering America Success Story November 19, 2012 More News Subscribe to News Updates Events Renewable Energy Market Update Webinar January 29, 2014 Strategic Energy Planning: Webinar February 26, 2014 Introduction to Wind Systems March 10, 2014 More Events Publications 2012 Market Report on Wind Technologies in Distributed Applications August 12, 2013 More Publications Features Sign up for the New England Wind Forum Newsletter. New England Wind Forum About the New England Wind Forum New England Wind Energy Education Project Historic Wind Development in New England State Activities Projects in New England

360

NREL: Wind Research - Small Wind Turbine Development  

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

Small Wind Turbine Development Small Wind Turbine Development A photo of Southwest Windpower's Skystream wind turbine in front of a home. PIX14936 Southwest Windpower's Skystream wind turbine. A photo of the Endurance wind turbine. PIX15006 The Endurance wind turbine. A photo of the Atlantic Orient Corporation 15/50 wind turbine at the National Wind Technology Center. PIX07301 The Atlantic Orient Corporation 15/50 wind turbine at the National Wind Technology Center. NREL supports continued market expansion of small wind turbines by funding manufacturers through competitive solicitations (i.e., subcontracts and/or grants) to refine prototype systems leading to commercialization. Learn more about the turbine development projects below. Skystream NREL installed and tested an early prototype of this turbine at the

Note: This page contains sample records for the topic "turbulence wind variability" 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

Turbines and turbulence  

Science Journals Connector (OSTI)

... Will wind turbines wreck the environment? Last month, the South China Morning Post published a news story ... dismissive official quoted probably has a point. There is no solid scientific evidence that wind turbines can trigger major changes in rainfall. And given Nature's conversations with atmospheric modellers ...

2010-12-22T23:59:59.000Z

362

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

363

Causality detection and turbulence in fusion plasmas  

E-Print Network [OSTI]

This work explores the potential of an information-theoretical causality detection method for unraveling the relation between fluctuating variables in complex nonlinear systems. The method is tested on some simple though nonlinear models, and guidelines for the choice of analysis parameters are established. Then, measurements from magnetically confined fusion plasmas are analyzed. The selected data bear relevance to the all-important spontaneous confinement transitions often observed in fusion plasmas, fundamental for the design of an economically attractive fusion reactor. It is shown how the present method is capable of clarifying the interaction between fluctuating quantities such as the turbulence amplitude, turbulent flux, and Zonal Flow amplitude, and uncovers several interactions that were missed by traditional methods.

van Milligen, B Ph; Ramisch, M; Estrada, T; Hidalgo, C; Alonso, A

2013-01-01T23:59:59.000Z

364

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

365

NREL: Wind Research - Offshore Wind Research  

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

Offshore Wind Research Offshore Wind Research Photo of a European offshore wind farm. Early progress in European Offshore Wind Energy over the last decade provides a glimpse into the vast potential of the global offshore resource. For more than eight years, NREL has worked with the Department of Energy to become an international leader in offshore wind energy research. Capabilities NREL's offshore wind capabilities focus on critical areas that reflect the long-term needs of the offshore wind energy industry and the U.S. Department of Energy including: Offshore Design Tools and Methods Offshore Standards and Testing Energy Analysis of Offshore Systems Offshore Wind Resource Characterization Grid Integration of Offshore Wind Key Research NREL documented the status of offshore wind energy in the United States in

366

NREL: Wind Research - Site Wind Resource Characteristics  

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

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

367

A Unified Framework for Reliability Assessment of Wind Energy Conversion Systems  

E-Print Network [OSTI]

1 A Unified Framework for Reliability Assessment of Wind Energy Conversion Systems Sebastian S a framework for assessing wind energy conversion systems (WECS) reliability in the face of external based on wind energy are: the impact of wind speed variability on system reliability [1]; WECS' reaction

Liberzon, Daniel

368

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

369

Characterization of Relativistic MHD Turbulence  

E-Print Network [OSTI]

The objective of this work is to understand if and how the characteristics of relativistic MHD turbulence may differ from those of nonrelativistic MHD turbulence. We accomplish this by studying the invariants in the relativistic case and comparing them to what we know of nonrelativistic turbulence. Although much work has been done to understand the dynamics of nonrelativistic systems (mostly for ideal incompressible fluids), there is minimal literature explicitly describing the dynamics of relativistic MHD turbulence. Many authors simply assume that relativistic turbulence has the same invariants and obeys the same inverse energy cascade as non-relativistic systems.

Garrison, David

2015-01-01T23:59:59.000Z

370

Wind Technologies & Evolving Opportunities (Presentation)  

SciTech Connect (OSTI)

This presentation covers opportunities for wind technology; wind energy market trends; an overview of the National Wind Technology Center near Boulder, Colorado; wind energy price and cost trends; wind turbine technology improvements; and wind resource characterization improvements.

Robichaud, R.

2014-07-01T23:59:59.000Z

371

Aerodynamic interference between two Darrieus wind turbines  

SciTech Connect (OSTI)

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

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

1981-04-01T23:59:59.000Z

372

An Exploration of Wind Energy & Wind Turbines | Department of...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

An Exploration of Wind Energy & Wind Turbines An Exploration of Wind Energy & Wind Turbines Below is information about the student activitylesson plan from your search. Grades...

373

A National Offshore Wind Strategy: Creating an Offshore Wind...  

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

A National Offshore Wind Strategy: Creating an Offshore Wind Energy Industry in the United States A National Offshore Wind Strategy: Creating an Offshore Wind Energy Industry in...

374

20% Wind Energy by 2030 - Chapter 2: Wind Turbine Technology...  

Office of Environmental Management (EM)

20% Wind Energy by 2030: Increasing Wind Energy's Contribution to U.S. Electricity Supply U.S. Offshore Wind Manufacturing and Supply Chain Development Wind Program Accomplishments...

375

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

376

Collegiate Wind Competition Engages Tomorrow's Wind Energy Innovators...  

Office of Environmental Management (EM)

Collegiate Wind Competition Engages Tomorrow's Wind Energy Innovators Collegiate Wind Competition Engages Tomorrow's Wind Energy Innovators January 6, 2014 - 10:00am Addthis 2014...

377

Wind for Schools Project Power System Brief, Wind Powering America...  

Wind Powering America (EERE)

Wind Powering America Fact Sheet Series Energy Efficiency & Renewable Energy Wind for Schools Project Power System Brief Wind for Schools Project Power System Brief Wind for...

378

Reactive capability limits of wind farms  

Science Journals Connector (OSTI)

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

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

2005-01-01T23:59:59.000Z

379

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.

380

A commotion over turbulence  

Science Journals Connector (OSTI)

... calculations) of dimensionless parameters of the reactor setup9. This has led to the IFS/PPPL model, named after the main institutions involved in its development. The basis for this ... other components besides the turbulence-induced diffusivity. Dorland and Kotschen-reuther have combined the IFS/PPPL diffusivity model with an assumed prescription for the density evolution and the boundary temperatures, ...

Benjamin A. Carreras

1997-01-23T23:59:59.000Z

Note: This page contains sample records for the topic "turbulence wind variability" 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

2009 Wind Technologies Market Report  

E-Print Network [OSTI]

Prepared for the Utility Wind Integration Group. Arlington,Arizona Public Service Wind Integration Cost Impact Study.an Order Revising the Wind Integration Rate for Wind Powered

Wiser, Ryan

2010-01-01T23:59:59.000Z

382

2010 Wind Technologies Market Report  

E-Print Network [OSTI]

2010. SPP WITF Wind Integration Study. Little Rock,an Order Revising the Wind Integration Rate for Wind PoweredPacifiCorp. 2010. 2010 Wind Integration Study. Portland,

Wiser, Ryan

2012-01-01T23:59:59.000Z

383

2011 Wind Technologies Market Report  

E-Print Network [OSTI]

and K. Porter. 2011. Wind Power and Electricity Markets.41 6. Wind Power Priceat Various Levels of Wind Power Capacity Penetration Wind

Bolinger, Mark

2013-01-01T23:59:59.000Z

384

Sandia National Laboratories: Wind Resources  

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

EnergyWind Resources Wind Resources Comments are closed. Renewable Energy Wind Energy Wind Plant Optimization Test Site Operations & Maintenance Safety: Test Facilities Capital...

385

Sandia National Laboratories: wind energy  

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

Wind Energy Manufacturing Lab Helps Engineers Improve Wind Power On November 15, 2011, in Energy, News, Partnership, Renewable Energy, Wind Energy Researchers at the Wind Energy...

386

Wind Energy | Department of Energy  

Office of Environmental Management (EM)

Wind Energy Wind Energy Below are resources for Tribes on wind energy technologies. 2012 Market Report on Wind Technologies in Distributed Applications Includes a breakdown of...

387

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

388

Modeling and Simulation of Wind Shear and Tower Shadow on Wind Turbines  

Science Journals Connector (OSTI)

Abstract This paper focuses on the modeling and simulation in Matlab/Simulink of the effects of wind shear and tower shadow in a three bladed, variable-speed wind turbine system. The study of the mechanical stress, the mitigation of the torque oscillations and the improvement of the aerodynamic efficiency below rated wind speed, can be attained with a proper modeling of the turbine system. This paper is a contribution on the study of the effects of wind shear and tower shadow, often approximated or neglected, that have to be properly understood, considered and modeled in order to get a better performance of the turbine system.

H. Sintra; V.M.F. Mendes; R. Melício

2014-01-01T23:59:59.000Z

389

NREL: Wind Research - Small Wind Turbine Research  

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

Small Wind Turbine Research Small Wind Turbine Research The National Renewable Energy Laboratory and U.S. Department of Energy (NREL/DOE) Small Wind Project's objectives are to reduce barriers to wind energy expansion, stabilize the market, and expand the number of small wind turbine systems installed in the United States. "Small wind turbine" refers to a turbine smaller than or equal to 100 kilowatts (kW). "Distributed wind" includes small and midsize turbines (100 kW through 1 megawatt [MW]). Since 1996, NREL's small wind turbine research has provided turbine testing, turbine development, and prototype refinement leading to more commercially available small wind turbines. Work is conducted under the following areas. You can also learn more about state and federal policies

390

Wind Vision Wind Farm | Open Energy Information  

Open Energy Info (EERE)

Wind Farm Wind Farm Jump to: navigation, search Name Wind Vision Wind Farm Facility Wind Vision Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner Wind Vision Developer Wind Vision Location St. Ansgar IA Coordinates 43.348224°, -92.888816° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":43.348224,"lon":-92.888816,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

391

High Winds Wind Farm | Open Energy Information  

Open Energy Info (EERE)

Winds Wind Farm Winds Wind Farm Jump to: navigation, search Name High Winds Wind Farm Facility High Winds Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner NextEra Energy Resources Developer NextEra Energy Resources Energy Purchaser PPM Energy Inc Location Solano County CA Coordinates 38.124844°, -121.764915° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":38.124844,"lon":-121.764915,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

392

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.

393

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)

394

Wind farm land suitability indexing using multi-criteria analysis  

Science Journals Connector (OSTI)

Wind farm siting can be considered as Multi Criteria Decision Making (MCDM) problem that consists of set of alternative locations and set of selection criteria. This study applied multi-criteria decision making approach using Analytical Hierarchy Process with Ordered Weigh Averaging AHP-OWA aggregation function to derive wind farm land suitability index and classification under Geographical Information System (GIS) environment. Linguistic quantifier’s version of AHP-OWA aggregation function was used to classify lands based on their suitability for wind farm installation. Different selection criteria were considered including economical (distance to road, terrain slope), social (urban area), environmental (historical locations, wildlife and natural reserves) and technical (wind power density, energy demand matching, percentage of sustainable wind, turbulence intensity, sand dunes). A case study of the proposed approach is implemented and presented for Oman.

Sultan Al-Yahyai; Yassine Charabi; Adel Gastli; Abdullah Al-Badi

2012-01-01T23:59:59.000Z

395

NREL: News Feature - NREL Software Tool a Boon for Wind Industry  

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

temperatures, and other variables alter the air flow and energy production at wind farms. Photo by Dennis Schroeder, NREL Wind energy is blowing away skeptics-it's so close to...

396

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

397

Market penetration of wind turbine concepts over the years Anca D. Hansen1  

E-Print Network [OSTI]

speed wind turbine concept with partial-scale power converter (DFIG) This configuration denotes the variable speed controlled wind turbine with doubly fed induction generator (DFIG) and pitch control

398

Impacts of large quantities of wind energy on the electric power system  

E-Print Network [OSTI]

Wind energy has been surging on a global scale. Significant penetration of wind energy is expected to take place in the power system, bringing new challenges because of the variability and uncertainty of this renewable ...

Yao, Yuan, S.M. Massachusetts Institute of Technology

2011-01-01T23:59:59.000Z

399

Wind Farm Monitoring at Lake Benton II Wind Power Project - Equipment Only: Cooperative Research and Development Final Report, CRADA Number CRD-08-275  

SciTech Connect (OSTI)

Long-term, high-resolution wind turbine and wind power plant output data are important to assess the impact of wind power on grid operations and to derive meaningful statistics for better understanding of the variability nature of wind power. These data are used for many research and analyses activities consistent with the Wind Program mission: Establish a database of long-term wind power similar to other long-term renewable energy resource databases (e.g. solar irradiance and hydrology); produce meaningful statistics about long-term variation of wind power, spatial and temporal diversity of wind power, and the correlation of wind power, other renewable energy resources, and utility load; provide high quality, realistic wind power output data for system operations impact studies and wind plant and forecasting model validation.

Gevorgian, V.

2014-06-01T23:59:59.000Z

400

Western Wind and Solar Integration Study  

SciTech Connect (OSTI)

The Western Wind and Solar Integration Study (WWSIS) is one of the largest regional wind and solar integration studies to date. It was initiated in 2007 to examine the operational impact of up to 35% energy penetration of wind, photovoltaics (PV), and concentrating solar power (CSP) on the power system operated by the WestConnect group of utilities in Arizona, Colorado, Nevada, New Mexico, and Wyoming (see study area map). WestConnect also includes utilities in California, but these were not included because California had already completed a renewable energy integration study for the state. This study was set up to answer questions that utilities, public utilities commissions, developers, and regional planning organizations had about renewable energy use in the west: (1) Does geographic diversity of renewable energy resource help mitigate variability; (2) How do local resources compare to out-of-state resources; (3) Can balancing area cooperation help mitigate variability; (4) What is the role and value of energy storage; (5) Should reserve requirements be modified; (6) What is the benefit of forecasting; and (7) How can hydropower help with integration of renewables? The Western Wind and Solar Integration Study is sponsored by the U.S. Department of Energy (DOE) and run by NREL with WestConnect as a partner organization. The study follows DOE's 20% Wind Energy by 2030 report, which did not find any technical barriers to reaching 20% wind energy in the continental United States by 2030. This study and its partner study, the Eastern Wind Integration and Transmission Study, performed a more in-depth operating impact analysis to see if 20% wind energy was feasible from an operational level. In DOE/NREL's analysis, the 20% wind energy target required 25% wind energy in the western interconnection; therefore, this study considered 20% and 30% wind energy to bracket the DOE analysis. Additionally, since solar is rapidly growing in the west, 5% solar was also considered in this study. The goal of the Western Wind and Solar Integration Study is to understand the costs and operating impacts due to the variability and uncertainty of wind, PV, and CSP on the grid. This is mainly an operations study, (rather than a transmission study), although different scenarios model different transmission build-outs to deliver power. Using a detailed power system production simulation model, the study identifies operational impacts and challenges of wind energy penetration up to 30% of annual electricity consumption.

Lew, D.; Piwko, R.; Jordan, G.; Miller, N.; Clark, K.; Freeman, L.; Milligan, M.

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "turbulence wind variability" 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

Wind pump systems  

Science Journals Connector (OSTI)

The application of wind mills for water pumping is of lesser importance ... it is useful to discuss this type of wind energy application in a wind energy book targeted at development and planning...

Prof. Dr.-Ing. Robert Gasch; Prof. Dr.-Ing. Jochen Twele

2012-01-01T23:59:59.000Z

402

NREL: Wind Research - Testing  

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

the National Wind Technology Center (NWTC) support the installation and testing of wind turbines that range in size from 400 watts to 5.0 megawatts. Engineers provide wind...

403

Fixed Offshore Wind Turbines  

Science Journals Connector (OSTI)

In this chapter, a perspective of offshore wind farms, applied concepts for fixed offshore wind turbines, and related statistics are given. One example of a large wind farm, which is successfully operating, is st...

Madjid Karimirad

2014-01-01T23:59:59.000Z

404

Wind Power Today  

SciTech Connect (OSTI)

Wind Power Today is an annual publication that provides an overview of the wind energy research conducted by the U.S. Department of Energy Wind and Hydropower Technologies Program.

Not Available

2006-05-01T23:59:59.000Z

405

Wind Power Today  

SciTech Connect (OSTI)

Wind Power Today is an annual publication that provides an overview of the wind energy research conducted by the U.S. Department of Energy Wind and Hydropower Technologies Program.

Not Available

2007-05-01T23:59:59.000Z

406

Modeling Turbulent Flow  

National Nuclear Security Administration (NNSA)

Turbulent Turbulent Flow with Implicit LES L.G. Margolin 1 Proceedings of the Joint Russian-American Five Laboratory Conference on Computational Mathematics/Physics 19-23 June, 2005 Vienna, Austria 1 Applied Physics Division, Los Alamos National Laboratory, Los Alamos, NM 87545, len@lanl.gov 1 Abstract Implicit large eddy simulation (ILES) is a methodology for modeling high Reynolds' num- ber flows that combines computational efficiency and ease of implementation with predictive calculations and flexible application. Although ILES has been used for more than fifteen years, it is only recently that significant effort has gone into providing a physical rationale that speaks to its capabilities and its limitations. In this talk, we will present new theoret- ical results aimed toward building a justification and discuss some remaining gaps in our understanding and our practical

407

Nonextensive statistical dynamics applied to wall turbulence  

E-Print Network [OSTI]

We apply a formalism of nonextensive statistical mechanics to experimental wall turbulence data, for the first time to our knowledge. Wind tunnel data for velocity differences a streamwise distance $r$ apart are compared to the prediction from theory as developed by Beck. The simplest theory, in which all free parameters are removed, is found to reproduce statistics for the wall-normal velocity component remarkably well, even for $r$ well beyond the corresponding integral scale, while the corresponding description of the streamwise velocity fluctuations is reasonable at separations below the integral scale. A least-squares 2-parameter fit is performed, and the dependence of the optimum parameter values on wall separation and $r$ is analysed. Both parameters are found to be approximately independent of wall-separation in the logarithmic sub-layer.

Simen Å Ellingsen; Per-Åge Krogstad

2014-02-10T23:59:59.000Z

408

Reynolds Number Invariance of the Structure Inclination Angle in Wall Turbulence Ivan Marusic*  

E-Print Network [OSTI]

Reynolds Number Invariance of the Structure Inclination Angle in Wall Turbulence Ivan Marusic using hot-film and hot-wire anemometry in a wind tunnel facility, and sonic anemometers and a purpose has not been available before. Structure inclination angles are inferred from the cross correlation

Marusic, Ivan

409

The Effect of Magnetic Turbulence Energy Spectra and Pickup Ions on the Heating of the  

E-Print Network [OSTI]

The Effect of Magnetic Turbulence Energy Spectra and Pickup Ions on the Heating of the Solar Wind C02101 (2010)], we have incorporated in the heating model the energy cascade rate based on Iroshnikov scale. Since in steady state, the heating rate is essentially the same as the energy cascade rate

Ng, Chung-Sang

410

Phenomenology for the decay of energy-containing eddies in homogeneous MHD turbulence  

E-Print Network [OSTI]

Phenomenology for the decay of energy-containing eddies in homogeneous MHD turbulence Murshed of simple, one-point phenomenological models for the decay of energy-containing eddies phenomenology has been previously verified against experiments in wind tunnels, and certain experimentally

Oughton, Sean

411

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

412

The National Wind Technology Center  

SciTech Connect (OSTI)

Wind energy research began at the Rocky Flats test site in 1976 when Rockwell International subcontracted with the Energy Research and Development Administration (ERDA). The Rocky Flats Plant was competitively selected from a number of ERDA facilities primarily because it experienced high instantaneous winds and provided a large, clear land area. By 1977, several small wind turbines were in place. During the facility`s peak of operation, in 1979-1980, researchers were testing as many as 23 small wind turbines of various configurations, including commercially available machines and prototype turbines developed under subcontract to Rocky Flats. Facilities also included 8-kW, 40-kW, and 225-kW dynamometers; a variable-speed test bed; a wind/hybrid test facility; a controlled velocity test facility (in Pueblo, Colorado); a modal test facility, and a multimegawatt switchgear facility. The main laboratory building was dedicated in July 1981 and was operated by the Rocky Flats Plant until 1984, when the Solar Energy Research Institute (SERI) and Rocky Flats wind energy programs were merged and transferred to SERI. SERI and now the National Renewable Energy Laboratory (NREL) continued to conduct wind turbine system component tests after 1987, when most program personnel were moved to the Denver WEst Office Park in Golden and site ownership was transferred back to Rocky Flats. The Combined Experiment test bed was installed and began operation in 1988, and the NREL structural test facility began operation in 1990. In 1993, the site`s operation was officially transferred to the DOE Golden Field Office that oversees NREL. This move was in anticipation of NREL`s renovation and reoccupation of the facility in 1994.

Thresher, R.W.; Hock, S.M. [National Renewable Energy Lab., Golden, CO (United States)] [National Renewable Energy Lab., Golden, CO (United States); Loose, R.R.; Cadogon, J.B.

1994-07-01T23:59:59.000Z

413

Transition to turbulence in ferrofluids  

E-Print Network [OSTI]

It is known that in classical fluids turbulence typically occurs at high Reynolds numbers. But can turbulence occur at low Reynolds numbers? Here we investigate the transition to turbulence in the classic Taylor-Couette system in which the rotating fluids are manufactured ferrofluids with magnetized nanoparticles embedded in liquid carriers. We find that, in the presence of a magnetic field turbulence can occur at Reynolds numbers that are at least one order of magnitude smaller than those in conventional fluids. This is established by extensive computational ferrohydrodynamics through a detailed bifurcation analysis and characterization of behaviors of physical quantities such as the energy, the wave number, and the angular momentum through the bifurcations. A striking finding is that, as the magnetic field is increased, the onset of turbulence can be determined accurately and reliably. Our results imply that experimental investigation of turbulence can be greatly facilitated by using ferrofluids, opening up...

Altmeyer, Sebastian; Lai, Ying-Cheng

2015-01-01T23:59:59.000Z

414

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

415

NREL: Wind Research - Midsize Wind Turbine Research  

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

Midsize Wind Turbine Research Midsize Wind Turbine Research To facilitate the development and commercialization of midsize wind turbines (turbines with a capacity rating of more than 100 kW up to 1 MW), the U.S. Department of Energy (DOE) and NREL launched the Midsize Wind Turbine Development Project. In its latest study, NREL determined that there is a substantial market for midsize wind turbines. One of the most significant barriers to the midsize turbine market is the lack of turbines available for deployment; there are few midsize turbines on the market today. The objectives of the Midsize Wind Turbine Development Project are to reduce the barriers to wind energy expansion by filling an existing domestic technology gap; facilitate partnerships; accelerate maturation of existing U.S. wind energy businesses; and incorporate process improvement

416

Diablo Winds Wind Farm | Open Energy Information  

Open Energy Info (EERE)

Diablo Winds Wind Farm Diablo Winds Wind Farm Facility Diablo Winds Wind Farm Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner NextEra Energy Resources Developer NextEra Energy Resources Energy Purchaser Pacific Gas & Electric Co Location Altamont Pass CA Coordinates 37.7347°, -121.652° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":37.7347,"lon":-121.652,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

417

Wind for Schools (Poster)  

SciTech Connect (OSTI)

As the United States dramatically expands wind energy deployment, the industry is challenged with developing a skilled workforce and addressing public resistance. Wind Powering America's Wind for Schools project addresses these issues by developing Wind Application Centers (WACs) at universities; WAC students assist in implementing school wind turbines and participate in wind courses, by installing small wind turbines at community "host" schools, by implementing teacher training with interactive curricula at each host school. This poster provides an overview of the first two years of the Wind for Schools project, primarily supporting activities in Colorado, Kansas, Nebraska, South Dakota, Montana, and Idaho.

Baring-Gould, I.

2010-05-01T23:59:59.000Z

418

Wind Turbine Tribology Seminar  

Broader source: Energy.gov [DOE]

Wind turbine reliability issues are often linked to failures of contacting components, such as bearings, gears, and actuators. Therefore, special consideration to tribological design in wind...

419

Wind energy bibliography  

SciTech Connect (OSTI)

This bibliography is designed to help the reader search for information on wind energy. The bibliography is intended to help several audiences, including engineers and scientists who may be unfamiliar with a particular aspect of wind energy, university researchers who are interested in this field, manufacturers who want to learn more about specific wind topics, and librarians who provide information to their clients. Topics covered range from the history of wind energy use to advanced wind turbine design. References for wind energy economics, the wind energy resource, and environmental and institutional issues related to wind energy are also included.

None

1995-05-01T23:59:59.000Z

420

Northern Wind Farm  

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

a draft environmental assessment (EA) on the proposed interconnection of the Northern Wind Farm (Project) in Roberts County, near the city of Summit, South Dakota. Northern Wind,...

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


421

Wind Program News  

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

eerewindwind-program-news en EERE Leadership Celebrates Offshore Wind in Maine http:energy.goveerearticleseere-leadership-celebrates-offshore-wind-maine

422

British wind band music.  

E-Print Network [OSTI]

??I have chosen to be assessed as an interpreter and conductor of British wind band music from the earliest writings for wind band up to,… (more)

Jones, GO

2005-01-01T23:59:59.000Z

423

WINDExchange: Wind Energy Ordinances  

Wind Powering America (EERE)

Wind Energy Ordinances Federal, state, and local regulations govern many aspects of wind energy development. The exact nature of the project and its location will largely drive the...

424

Wind Program: WINDExchange  

Wind Powering America (EERE)

Version Bookmark and Share WINDExchange logo WINDExchange is the U.S. Department of Energy (DOE) Wind Program's platform for disseminating credible information about wind...

425

WINDExchange: Siting Wind Turbines  

Wind Powering America (EERE)

Wind Wildlife Institute (AWWI) facilitates timely and responsible development of wind energy, while protecting wildlife and wildlife habitat. AWWI was created and is sustained by...

426

WINDExchange: Collegiate Wind Competition  

Wind Powering America (EERE)

& Teaching Materials Resources Collegiate Wind Competition The U.S. Department of Energy (DOE) Collegiate Wind Competition challenges interdisciplinary teams of undergraduate...

427

ARM - Wind Chill Calculations  

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

FAQ Just for Fun Meet our Friends Cool Sites Teachers Teachers' Toolbox Lesson Plans Wind Chill Calculations Wind Chill is the apparent temperature felt on the exposed human...

428

NONIDEAL MAGNETOHYDRODYNAMIC TURBULENT DECAY IN MOLECULAR CLOUDS  

SciTech Connect (OSTI)

It is well known that nonideal magnetohydrodynamic (MHD) effects are important in the dynamics of molecular clouds: both ambipolar diffusion and possibly the Hall effect have been identified as significant. We present the results of a suite of simulations with a resolution of 512{sup 3} of turbulent decay in molecular clouds, incorporating a simplified form of both ambipolar diffusion and the Hall effect simultaneously. The initial velocity field in the turbulence is varied from being super-Alfvenic and hypersonic, through to trans-Alfvenic but still supersonic. We find that ambipolar diffusion increases the rate of decay of the turbulence increasing the decay from t {sup -1.25} to t {sup -1.4}. The Hall effect has virtually no impact in this regard. The power spectra of density, velocity, and the magnetic field are all affected by the nonideal terms, being steepened significantly when compared with ideal MHD turbulence with exponents. The density power-spectra components change from {approx}1.4 to {approx}2.1 for the ideal and nonideal simulations respectively, and power spectra of the other variables all show similar modifications when nonideal effects are considered. Again, the dominant source of these changes is ambipolar diffusion rather than the Hall effect. There is also a decoupling between the velocity field and the magnetic field at short length scales. The Hall effect leads to enhanced magnetic reconnection, and hence less power, at short length scales. The dependence of the velocity dispersion on the characteristic length scale is studied and found not to be power law in nature.

Downes, T. P. [School of Cosmic Physics, Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland); O'Sullivan, S. [National Centre for Plasma Science and Technology, Dublin City University, Glasnevin, Dublin 9 (Ireland)], E-mail: turlough.downes@dcu.ie

2009-08-20T23:59:59.000Z

429

Quantum ghost imaging through turbulence  

SciTech Connect (OSTI)

We investigate the effect of turbulence on quantum ghost imaging. We use entangled photons and demonstrate that for a specific experimental configuration the effect of turbulence can be greatly diminished. By decoupling the entangled photon source from the ghost-imaging central image plane, we are able to dramatically increase the ghost-image quality. When imaging a test pattern through turbulence, this method increases the imaged pattern visibility from V=0.15{+-}0.04 to 0.42{+-}0.04.

Dixon, P. Ben; Howland, Gregory A.; Howell, John C. [Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States); Chan, Kam Wai Clifford [Rochester Optical Manufacturing Company, Rochester, New York 14606 (United States); O'Sullivan-Hale, Colin; Rodenburg, Brandon [Institute of Optics, University of Rochester, Rochester, New York 14627 (United States); Hardy, Nicholas D.; Shapiro, Jeffrey H. [Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Simon, D. S.; Sergienko, A. V. [Department of Electrical and Computer Engineering, Boston University, Boston, Massachusetts 02215 (United States); Boyd, R. W. [Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States); Institute of Optics, University of Rochester, Rochester, New York 14627 (United States)

2011-05-15T23:59:59.000Z

430

Characterization of Fuego for laminar and turbulent natural convection heat transfer.  

SciTech Connect (OSTI)

A computational fluid dynamics (CFD) analysis is conducted for internal natural convection heat transfer using the low Mach number code Fuego. The flow conditions under investigation are primarily laminar, transitional, or low-intensity level turbulent flows. In the case of turbulent boundary layers at low-level turbulence or transitional Reynolds numbers, the use of standard wall functions no longer applies, in general, for wall-bounded flows. One must integrate all the way to the wall in order to account for gradients in the dependent variables in the viscous sublayer. Fuego provides two turbulence models in which resolution of the near-wall region is appropriate. These models are the v2-f turbulence model and a Launder-Sharma, low-Reynolds number turbulence model. Two standard geometries are considered: the annulus formed between horizontal concentric cylinders and a square enclosure. Each geometry emphasizes wall shear flow and complexities associated with turbulent or near turbulent boundary layers in contact with a motionless core fluid. Overall, the Fuego simulations for both laminar and turbulent flows compared well to measured data, for both geometries under investigation, and to a widely accepted commercial CFD code (FLUENT).

Francis, Nicholas Donald, Jr. (,; .)

2005-08-01T23:59:59.000Z

431

Filtering Turbulent Sparsely Observed Geophysical Flows  

Science Journals Connector (OSTI)

Filtering sparsely turbulent signals from nature is a central problem of contemporary data assimilation. Here, sparsely observed turbulent signals from nature are generated by solutions of two-layer quasigeostrophic models with turbulent cascades ...

John Harlim; Andrew J. Majda

2010-04-01T23:59:59.000Z

432

Module Handbook Specialisation Wind Energy  

E-Print Network [OSTI]

of Wind Turbines Module name: Wind potential, Aerodynamics & Loading of Wind Turbines Section Classes Evaluation of Wind Energy Potential Wind turbine Aerodynamics Static and dynamic Loading of Wind turbines Wind turbine Aerodynamics Static and dynamic Loading of Wind turbines Credit points 8 CP

Habel, Annegret

433

Sandia National Laboratories: Wind Energy  

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

specialprogramsslide5 windplantoptslide4 rotorinnovationslide3 offshorewindslide2 Materialsslide1 Wind Energy Wind Plant Optimization Materials,...

434

ARM - PI Product - Cloud-Scale Vertical Velocity and Turbulent Dissipation  

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

ProductsCloud-Scale Vertical Velocity and Turbulent ProductsCloud-Scale Vertical Velocity and Turbulent Dissipation Rate Retrievals Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send PI Product : Cloud-Scale Vertical Velocity and Turbulent Dissipation Rate Retrievals Site(s) NSA General Description Time-height fields of retrieved in-cloud vertical wind velocity and turbulent dissipation rate, both retrieved primarily from vertically-pointing, Ka-band cloud radar measurements. Files are available for manually-selected, stratiform, mixed-phase cloud cases observed at the North Slope of Alaska (NSA) site during periods covering the Mixed-Phase Arctic Cloud Experiment (MPACE, late September through early November 2004) and the Indirect and Semi-Direct Aerosol Campaign (ISDAC, April-early May

435

Alfvén wave collisions, the fundamental building block of plasma turbulence. IV. Laboratory experiment  

SciTech Connect (OSTI)

Turbulence is a phenomenon found throughout space and astrophysical plasmas. It plays an important role in solar coronal heating, acceleration of the solar wind, and heating of the interstellar medium. Turbulence in these regimes is dominated by Alfvén waves. Most turbulence theories have been established using ideal plasma models, such as incompressible MHD. However, there has been no experimental evidence to support the use of such models for weakly to moderately collisional plasmas which are relevant to various space and astrophysical plasma environments. We present the first experiment to measure the nonlinear interaction between two counterpropagating Alfvén waves, which is the building block for astrophysical turbulence theories. We present here four distinct tests that demonstrate conclusively that we have indeed measured the daughter Alfvén wave generated nonlinearly by a collision between counterpropagating Alfvén waves.

Drake, D. J. [Department of Physics, Astronomy, and Geosciences, Valdosta State University, Valdosta, Georgia 31698 (United States)] [Department of Physics, Astronomy, and Geosciences, Valdosta State University, Valdosta, Georgia 31698 (United States); Schroeder, J. W. R.; Howes, G. G.; Kletzing, C. A.; Skiff, F. [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States)] [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States); Carter, T. A.; Auerbach, D. W. [Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States)] [Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States)

2013-07-15T23:59:59.000Z

436

Global simulations of magnetorotational turbulence – II. Turbulent energetics  

Science Journals Connector (OSTI)

......Importantly, as we are using an ideal MHD simulation, this shows that...construct a simplified energy flow diagram, which is shown in Fig...the heart of self-sustaining MHD turbulence in accretion discs. Figure 14. Energy flow diagram for turbulence in a global disc......

E. R. Parkin

2014-01-01T23:59:59.000Z

437

Modeling the Benefits of Storage Technologies to Wind Power  

SciTech Connect (OSTI)

Rapid expansion of wind power in the electricity sector is raising questions about how wind resource variability might affect the capacity value of wind farms at high levels of penetration. Electricity storage, with the capability to shift wind energy from periods of low demand to peak times and to smooth fluctuations in output, may have a role in bolstering the value of wind power at levels of penetration envisioned by a new Department of Energy report ('20% Wind by 2030, Increasing Wind Energy's Contribution to U.S. Electricity Supply'). This paper quantifies the value storage can add to wind. The analysis was done employing the Regional Energy Deployment System (ReEDS) model, formerly known as the Wind Deployment System (WinDS) model. ReEDS was used to estimate the cost and development path associated with 20% penetration of wind in the report. ReEDS differs from the WinDS model primarily in that the model has been modified to include the capability to build and use three storage technologies: pumped-hydroelectric storage (PHS), compressed-air energy storage (CAES), and batteries. To assess the value of these storage technologies, two pairs of scenarios were run: business-as-usual, with and without storage; 20% wind energy by 2030, with and without storage. This paper presents the results from those model runs.

Sullivan, P.; Short, W.; Blair, N.

2008-06-01T23:59:59.000Z

438

NONRESONANT INTERACTION OF CHARGED ENERGETIC PARTICLES WITH LOW-FREQUENCY NONCOMPRESSIVE TURBULENCE: NUMERICAL SIMULATION  

SciTech Connect (OSTI)

A new method for simulating the three-dimensional dynamics of charged energetic particles in very broadband noncompressive magnetic turbulence is introduced. All scales within the primary inertial range of the turbulence observed in the solar wind near 1 AU are now included for the independent computations of both the particle dynamics and the turbulent magnetic field lines (MFLs). While previous theories of resonant particle pitch-angle (PA) scattering and transport in interplanetary magnetic fields had favored interpreting the observed depletions in the electron PA distributions (PADs) around 90 Degree-Sign PA as evidence of poor scattering at low PA cosines, the computed particle dynamics reveal a very different reality. The MFL directions now vary on many scales, and the PADs are depleted around 90 Degree-Sign PA due to nonresonant filtering of the particles that propagate at too large an angle to the local magnetic field. Rather than being too weak, the scattering through 90 Degree-Sign PA is actually so strong that the particles (electrons and protons/ions) are reflected and trapped in the turbulent magnetic fields. While the low-frequency nonresonant turbulence produces ubiquitous magnetic traps that only let through particles with the most field-aligned velocities, higher-frequency near-gyroscale turbulence, when present, enhances particle transport by allowing the particles to navigate between magnetic traps. Finally, visualizing both particle trajectories and MFLs in the very same turbulence reveals a powerful tool for understanding the effects of the turbulent fields on the particle dynamics and cross-field transport. Some cross-field-line scattering, strongly amplified by MFL dispersal, results in a strong cross-field scattering of the particles. From this visualization, it also appears that near-gyroscale turbulence, previously known as gyroresonant turbulence, does not resonantly interact with the particles. The interaction between particles and fields at or near the gyroscale, though potentially strong, does not actually involve the periodic driving of a true resonance.

Ragot, B. R. [Helio Research, P.O. Box 1414, Nashua, NH 03061 (United States)

2012-10-20T23:59:59.000Z

439

GROWTH OF A LOCALIZED SEED MAGNETIC FIELD IN A TURBULENT MEDIUM  

SciTech Connect (OSTI)

Turbulence dynamo deals with the amplification of a seed magnetic field in a turbulent medium and has been studied mostly for uniform or spatially homogeneous seed magnetic fields. However, some astrophysical processes (e.g., jets from active galaxies, galactic winds, or ram-pressure stripping in galaxy clusters) can provide localized seed magnetic fields. In this paper, we numerically study amplification of localized seed magnetic fields in a turbulent medium. Throughout the paper, we assume that the driving scale of turbulence is comparable to the size of the system. Our findings are as follows. First, turbulence can amplify a localized seed magnetic field very efficiently. The growth rate of magnetic energy density is as high as that for a uniform seed magnetic field. This result implies that magnetic field ejected from an astrophysical object can be a viable source of a magnetic field in a cluster. Second, the localized seed magnetic field disperses and fills the whole system very fast. If turbulence in a system (e.g., a galaxy cluster or a filament) is driven at large scales, we expect that it takes a few large-eddy turnover times for the magnetic field to fill the whole system. Third, growth and turbulence diffusion of a localized seed magnetic field are also fast in high magnetic Prandtl number turbulence. Fourth, even in decaying turbulence, a localized seed magnetic field can ultimately fill the whole system. Although the dispersal rate of the magnetic field is not fast in purely decaying turbulence, it can be enhanced by an additional forcing.

Cho, Jungyeon; Yoo, Hyunju, E-mail: jcho@cnu.ac.kr [Department of Astronomy and Space Science, Chungnam National University, Daejeon (Korea, Republic of)

2012-11-10T23:59:59.000Z

440

West Winds Wind Farm | Open Energy Information  

Open Energy Info (EERE)

West Winds Wind Farm West Winds Wind Farm Facility West Winds Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner Caithness Developer SeaWest Energy Purchaser Southern California Edison/PacifiCorp Location San Gorgonio CA Coordinates 33.9095°, -116.734° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":33.9095,"lon":-116.734,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

Note: This page contains sample records for the topic "turbulence wind variability" 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

Howard County- Wind Ordinance  

Broader source: Energy.gov [DOE]

This ordinance sets up provisions for allowing small wind energy systems in various zoning districts.

442

Chapter 2 Offshore Wind Power Stations  

Science Journals Connector (OSTI)

Publisher Summary This chapter presents the historical background and development of offshore wind power stations. As early as 1890, windmills were put to work to produce electricity and more than 50,000 mills were in use in the United States alone in the twenties and thirties. Their decline was precipitated by the Rural Electrification Program. According to the San Francisco based Transaction Energy Projects Institute, offshore windmills could generate all the electrical power needed by northern California. Ocean winds have of course provided energy to windmills for centuries. In 1976, a study was commissioned by the (U.S.) Energy Research and Development Administration to ascertain and assess the economic value of offshore multi units aiming at identification and classification of area offshore types, assessing utility requirements for offshore power systems. It includes developing installation concepts including various floating and bottom-mounted designs, assessing current WECS (wind energy converter systems) for use in offshore environments, assessing various electric transmission and hydrogen delivery concepts, and performing an economic assessment, providing tradeoffs for variables such as distance offshore, climate, bottom and wave characteristics and average wave velocities. It is suggested that high wind velocity sites must be identified because the energy flow increases with the cube of the wind velocity; the kinetic energy of the wind passing through the area swept by the blades of a turbine is the energy available to that wind turbine. An average wind speed distribution is required.

1993-01-01T23:59:59.000Z

443

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

444

NREL: Energy Analysis - Wind Power Results - Life Cycle Assessment  

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

Wind LCA Harmonization (Fact Sheet) Wind LCA Harmonization (Fact Sheet) Cover of the LWind LCA Harmonization Fact Sheet Download the Fact Sheet Wind Power Results - Life Cycle Assessment Harmonization To better understand the state of knowledge of greenhouse gas (GHG) emissions from utility-scale wind power systems, NREL developed and applied a systematic approach to review life cycle assessment literature, identify sources of variability and, where possible, reduce variability in GHG emissions estimates through a meta-analytical process called "harmonization." Over the last 30 years, several hundred life cycle assessments have been conducted for wind power technologies with wide-ranging results. Harmonization for onshore and offshore wind power systems was performed by adjusting published greenhouse gas estimates to achieve:

445

E-Print Network 3.0 - advanced wind turbine Sample Search Results  

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

models and advanced control strategies... .139) Track: Technical VARIABLE SPEED WIND TURBINES - FAULT RIDE-THROUGH AND GRID SUPPORT CAPABILITIES... is on the fault ride through...

446

Wind turbine power generation emulation via doubly fed induction generator control .  

E-Print Network [OSTI]

??In this thesis, we emulate a Wind Turbine Generator by driving a Doubly Fed Induction Generator (DFIG) via a DC motor with variable input torque… (more)

Edwards, Gregory W.

2009-01-01T23:59:59.000Z

447

An investigation of the relationships between mountain waves and clear air turbulence encountered by the XB-70 airplane in the stratosphere  

E-Print Network [OSTI]

. . . . . . . . , . . . ~ . ~ INTRODUCTION BACKGROUND TO THE PROBLEM Theory of Mountain Waves Mountain Waves and Clear Air Turbulence (CAT). Page iv v vi viii The Vertical Propagation and Transfer of Energy of Mountain Waves into the Stratosphere The Influence of Wind... and wave energy under the influence of wind shear (Booker and Bretherton, 1967). A critical level, if it exists, is the level at which the horizontal phase velocity of the wave equals the mean wind speed. If a wave passes through a criti- cal level...

Incrocci, Thomas Paul

2012-06-07T23:59:59.000Z

448

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

449

Turbulent Magnetic Reconnection Near a  

E-Print Network [OSTI]

Turbulent Magnetic Reconnection Near a 3D Magnetic Null C. S. Ng Space Science Center Institute for the Study of Earth, Oceans, and Space University of New Hampshire, Durham, NH 03824 #12;Turbulent Magnetic Reconnection Near a 3D Magnetic Null C. S. Ng, chung-sang.ng@unh.edu, Space Science Center, Institute

Ng, Chung-Sang

450

Advances in compressible turbulent mixing  

SciTech Connect (OSTI)

This volume includes some recent additions to original material prepared for the Princeton International Workshop on the Physics of Compressible Turbulent Mixing, held in 1988. Workshop participants were asked to emphasize the physics of the compressible mixing process rather than measurement techniques or computational methods. Actual experimental results and their meaning were given precedence over discussions of new diagnostic developments. Theoretical interpretations and understanding were stressed rather than the exposition of new analytical model developments or advances in numerical procedures. By design, compressibility influences on turbulent mixing were discussed--almost exclusively--from the perspective of supersonic flow field studies. The papers are arranged in three topical categories: Foundations, Vortical Domination, and Strongly Coupled Compressibility. The Foundations category is a collection of seminal studies that connect current study in compressible turbulent mixing with compressible, high-speed turbulent flow research that almost vanished about two decades ago. A number of contributions are included on flow instability initiation, evolution, and transition between the states of unstable flow onset through those descriptive of fully developed turbulence. The Vortical Domination category includes theoretical and experimental studies of coherent structures, vortex pairing, vortex-dynamics-influenced pressure focusing. In the Strongly Coupled Compressibility category the organizers included the high-speed turbulent flow investigations in which the interaction of shock waves could be considered an important source for production of new turbulence or for the enhancement of pre-existing turbulence. Individual papers are processed separately.

Dannevik, W.P.; Buckingham, A.C.; Leith, C.E. [eds.

1992-01-01T23:59:59.000Z

451

Wind Powering America  

Wind Powering America (EERE)

These news items are notable additions These news items are notable additions to the Wind Powering America Web site. The Wind Powering America Web site reports recent national and state wind market changes by cataloging wind activities such as wind resource maps, small wind consumer's guides, local wind workshops, news articles, and publications in the areas of policy, public power, small wind, Native Americans, agricultural sector, economic development, public lands, and schools. en-us julie.jones@nrel.gov (Julie Jones) http://www.windpoweringamerica.gov/images/wpa_logo_sm.jpg Wind Powering America http://www.windpoweringamerica.gov/ Nominate an Electric Cooperative for Wind Power Leadership Award by January 15 http://www.windpoweringamerica.gov/filter_detail.asp?itemid=4076 http://www.windpoweringamerica.gov/filter_detail.asp?itemid=4076 Mon, 16

452

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 in¯uences of solar variability. The response of the prevailing wind to the 11-year solar cycle

Paris-Sud XI, Université de

453

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

454

New England Wind Forum: New England Wind Resources  

Wind Powering America (EERE)

New England Wind Forum About the New England Wind Forum New England Wind Energy Education Project Historic Wind Development in New England State Activities Projects in New England Building Wind Energy in New England Wind Resources Wind Power Technology Economics 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 New England Wind Resources Go to the Vermont wind resource map. Go to the New Hampshire wind resource map. Go to the Maine wind resource map. Go to the Massachusetts wind resource map. Go to the Connecticut wind resource map. Go to the Rhode Island wind resource map. New England Wind Resource Maps Wind resources maps of Connecticut, Massachusetts, Maine, New Hampshire, Rhode Island, and Vermont.

455

Wind Resource Maps (Postcard)  

SciTech Connect (OSTI)

The U.S. Department of Energy's Wind Powering America initiative provides high-resolution wind maps and estimates of the wind resource potential that would be possible from development of the available windy land areas after excluding areas unlikely to be developed. This postcard is a marketing piece that stakeholders can provide to interested parties; it will guide them to Wind Powering America's online wind energy resource maps.

Not Available

2011-07-01T23:59:59.000Z

456

Wind energy offers considerable promise; the wind itself is free,  

E-Print Network [OSTI]

Wind energy offers considerable promise; the wind itself is free, wind power is clean. One of these sources, wind energy, offers considerable promise; the wind itself is free, wind power is clean, and it is virtually inexhaustible. In recent years, research on wind energy has accelerated

Langendoen, Koen

457

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

458

Electromagnetic torque analysis of a DFIG for wind turbines  

Science Journals Connector (OSTI)

Electromagnetic torque of doubly fed induction generator (DFIG) is a consequence of the rotor and stator supply. The stator voltage has a fixed amount and frequency. The rotor voltage of the DFIG as a part of a wind turbine has a variable amount and ... Keywords: DFIG, electromagnetic torque, renewable energy, wind turbine

Jurica Smajo; Dinko Vukadinovic

2008-05-01T23:59:59.000Z

459

Seasonal Forecasting of Extreme Wind and Precipitation Frequencies in Europe  

E-Print Network [OSTI]

Seasonal Forecasting of Extreme Wind and Precipitation Frequencies in Europe Matthew J. Swann;Abstract Flood and wind damage to property and livelihoods resulting from extreme precipitation events variability of these extreme events can be closely related to the large-scale atmospheric circulation

Feigon, Brooke

460

Western Wind and Solar Integration Study Phase 2 (Fact Sheet)  

SciTech Connect (OSTI)

This is one-page, two-sided fact sheet presents high-level summary results of the Western Wind and Solar Integration Study Phase 2, which examined operational impacts of high penetrations of variable renewable generation in the West.

Not Available

2013-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "turbulence wind variability" 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

Western Wind and Solar Integration Study: Phase 2 (Presentation)  

SciTech Connect (OSTI)

This presentation summarizes the scope and results of the Western Wind and Solar Integration Study Phase 2, which examined operational impacts of high penetrations of variable renewable generation in the West.

Lew, D.; Brinkman, G.; Ibanez, E.; Lefton, S.; Kumar, N.; Venkataraman, S.; Jordan, G.

2013-09-01T23:59:59.000Z

462

Characteristics of Wind Turbines Under Normal and Fault Conditions: Preprint  

SciTech Connect (OSTI)

This paper investigates the characteristics of a variable-speed wind turbine connected to a stiff or weak grid under normal and fault conditions and the role of reactive power compensation.

Muljadi, E.; Butterfield, C. P.; Parsons, B.; Ellis, A.

2007-02-01T23:59:59.000Z

463

Environmental Vertical Wind Shear with Hurricane Bertha (1996)  

Science Journals Connector (OSTI)

Hurricane Bertha (1996) was influenced by vertical wind shear with highly variable direction and magnitude. The paper describes a unique method for determining the vertical tilt of a tropical cyclone vortex using satellite and aircraft data. ...

Raymond M. Zehr

2003-04-01T23:59:59.000Z

464

Wind Energy Atlas of Brazil | Open Energy Information  

Open Energy Info (EERE)

Energy Atlas of Brazil Energy Atlas of Brazil Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Wind Energy Atlas of Brazil Focus Area: Renewable Energy Topics: Potentials & Scenarios Website: 130.226.17.201/extra/web_docs/windmaps/Brazil_wind_map.pdf Equivalent URI: cleanenergysolutions.org/content/wind-energy-atlas-brazil,http://clean Language: English Policies: Deployment Programs DeploymentPrograms: Technical Assistance The maps provided in this resource result from a surface wind modelling tool called MesoMap that estimates the wind potential over the Brazilian territory by simulating the atmosphere dynamics of the wind regime and the related meteorological variables from validated atmosphere pressure-data samples. References Retrieved from "http://en.openei.org/w/index.php?title=Wind_Energy_Atlas_of_Brazil&oldid=514616

465

NREL: Wind Research - WindPACT  

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

WindPACT WindPACT The Wind Partnerships for Advanced Component Technology (WindPACT) studies were conducted to assist industry by testing innovative components, such as advanced blades and drivetrains, to lower the cost of energy. Specific goals included: Foster technological advancements to reduce the cost of wind energy Determine probable size ranges of advanced utility-scale turbines over the next decade for U.S. application Evaluate advanced concepts that are necessary to achieve objectives of cost and size for future turbines Identify and solve technological hurdles that may block industry from taking advantage of promising technology Design, fabricate, and test selected advanced components to prove their viability Support wind industry through transfer of technology from

466

Wind | Department of Energy  

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

Wind Wind Wind America is home to one of the largest and fastest growing wind markets in the world. Watch the video to learn more about the latest trends in the U.S. wind power market and join us this Thursday, August 8 at 3 pm ET for a Google+ Hangout on wind energy in America. The United States is home to one of the largest and fastest growing wind markets in the world. To stay competitive in this sector, the Energy Department invests in wind projects, both on land and offshore, to advance technology innovations, create job opportunities and boost economic growth. Moving forward, the U.S. wind industry remains a critical part of the Energy Department's all-of-the-above energy strategy to cut carbon pollution, diversify our energy economy and bring the next-generation of

467

Offshore Wind Projects | Department of Energy  

Office of Environmental Management (EM)

Offshore Wind Projects Offshore Wind Projects This report covers the Wind and Water Power Program's offshore wind energy projects from fiscal years 2006 to 2014. Offshore Wind...

468

NREL: Wind Research - Offshore Wind Research  

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

standards Third-party design verification of innovative floating and fixed-bottom wind turbines NREL's standards and testing capabilities address the need to validate our...

469

Characterization of wind noise by the boundary layer meteorology  

Science Journals Connector (OSTI)

The fluctuations in pressure generated by turbulent motions of the atmospheric boundary layer are a principal noise source in outdoor acoustic measurements. The mechanics of wind noise involve not only stagnation pressure fluctuations at the sensor but also shearing and self-interaction of turbulence throughout the flow particularly at low frequencies. The contributions of these mechanisms can be described by the boundary-layer meteorology. An experiment was conducted at the National Wind Institute's 200-meter meteorological tower located outside Lubbock Texas in the Llano Estacado region. For two days a 44-element 400-meter diameter array of unscreened NCPA-UMX infrasound sensors recorded wind noise continuously while the tower and a Doppler SODAR measured vertical profiles of the boundary layer. Analysis of the fluctuating pressure with the meteorological data shows that the statistical structure of wind noise depends on both mean velocity distribution and buoyant stability. The root-mean-square pressure exhibits distinct scalings for stable and unstable stratification. Normalization of the pressure power spectral density depends on the outer scales. In stable conditions the kurtosis of the wind noise increases with Reynolds number. Measures of noise intermittency are explored with respect to the meteorology.

2014-01-01T23:59:59.000Z

470

Impact of turbulence, land surface, and radiation parameterizations on simulated boundary layer properties in a coastal environment  

E-Print Network [OSTI]

structure and wind patterns can be highly variable due to a combination of sea- land breeze circulations, strong nocturnal low-level jets, and larger-scale diurnal wind oscillations with the oscillation period close to one diurnal cycle because of the proximity to the critical latitude. These complex wind

Clements, Craig

471

Memory effects in turbulent transport  

E-Print Network [OSTI]

In the mean-field theory of magnetic fields, turbulent transport, i.e. the turbulent electromotive force, is described by a combination of the alpha effect and turbulent magnetic diffusion, which are usually assumed to be proportional respectively to the mean field and its spatial derivatives. For a passive scalar there is just turbulent diffusion, where the mean flux of concentration depends on the gradient of the mean concentration. However, these proportionalities are approximations that are valid only if the mean field or the mean concentration vary slowly in time. Examples are presented where turbulent transport possesses memory, i.e. where it depends crucially on the past history of the mean field. Such effects are captured by replacing turbulent transport coefficients with time integral kernels, resulting in transport coefficients that depend effectively on the frequency or the growth rate of the mean field itself. In this paper we perform numerical experiments to find the characteristic timescale (or memory length) of this effect as well as simple analytical models of the integral kernels in the case of passive scalar concentrations and kinematic dynamos. The integral kernels can then be used to find self-consistent growth or decay rates of the mean fields. In mean-field dynamos the growth rates and cycle periods based on steady state values of alpha effect and turbulent diffusivity can be quite different from the actual values.

Alexander Hubbard; Axel Brandenburg

2008-11-17T23:59:59.000Z

472

Kinetic dissipation and anisotropic heating in a turbulent collisionless plasma  

E-Print Network [OSTI]

The kinetic evolution of the Orszag-Tang vortex is studied using collisionless hybrid simulations. In the magnetohydrodynamic regime this vortex leads rapidly to broadband turbulence. Significant differences from MHD arise at small scales, where the fluid scale energy dissipates into heat almost exclusively through the magnetic field because the protons are decoupled from the magnetic field. Although cyclotron resonance is absent, the protons heat preferentially in the plane perpendicular to the mean field, as in the corona and solar wind. Effective transport coefficients are calculated.

Parashar, T N; Cassak, P A; Matthaeus, W H

2008-01-01T23:59:59.000Z

473

2012 Wind Technologies Market Report  

E-Print Network [OSTI]

Colorado: Xcel Energy. 2012 Wind Technologies Market ReportOperator. 2012 Wind Technologies Market Report Chadbourne &Power Company. 2012 Wind Technologies Market Report EnerNex

Wiser, Ryan

2014-01-01T23:59:59.000Z

474

2011 Wind Technologies Market Report  

E-Print Network [OSTI]

2010. SPP WITF Wind Integration Study. Little Rock,GE Energy. 2011a. Oahu Wind Integration Study Final Report.PacifiCorp. 2010. 2010 Wind Integration Study. Portland,

Bolinger, Mark

2013-01-01T23:59:59.000Z

475

NREL: Wind Research - @NWTC Newsletter  

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

NREL Investigates the Logistics of Transporting and Installing Bigger, Taller Wind Turbines NREL Plays Founding, Developmental Role in Major Wind Journal Boosting Wind Plant...

476

2012 Wind Technologies Market Report  

E-Print Network [OSTI]

Department of Energy (DOE). 2008. 20% Wind Energy by2030: Increasing Wind Energy’s Contribution to U.S.Integrating Midwest Wind Energy into Southeast Electricity

Wiser, Ryan

2014-01-01T23:59:59.000Z

477

Sandia National Laboratories: Wind Power  

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

Wind Energy Staff On March 24, 2011, in Wind Energy On November 10, 2010, in Wind Plant Opt. Rotor Innovation Materials, Reliability & Standards Siting & Barrier Mitigation...

478

Sandia National Laboratories: wind manufacturing  

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

manufacturing Wind Energy Manufacturing Lab Helps Engineers Improve Wind Power On November 15, 2011, in Energy, News, Partnership, Renewable Energy, Wind Energy Researchers at the...

479

Compound cooling flow turbulator for turbine component  

DOE Patents [OSTI]

Multi-scale turbulation features, including first turbulators (46, 48) on a cooling surface (44), and smaller turbulators (52, 54, 58, 62) on the first turbulators. The first turbulators may be formed between larger turbulators (50). The first turbulators may be alternating ridges (46) and valleys (48). The smaller turbulators may be concave surface features such as dimples (62) and grooves (54), and/or convex surface features such as bumps (58) and smaller ridges (52). An embodiment with convex turbulators (52, 58) in the valleys (48) and concave turbulators (54, 62) on the ridges (46) increases the cooling surface area, reduces boundary layer separation, avoids coolant shadowing and stagnation, and reduces component mass.

Lee, Ching-Pang; Jiang, Nan; Marra, John J; Rudolph, Ronald J

2014-11-25T23:59:59.000Z

480

NREL: Wind Research - Projects  

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

Projects Projects NREL's wind energy research and development projects focus on reducing the cost of wind technology and expanding access to wind energy sites. Our specialized technical expertise, comprehensive design and analysis tools, and unique testing facilities help industry overcome challenges to bringing new wind technology to the marketplace. Some of these success stories are described in NREL's Wind R&D Success Stories. We also work closely with universities and other national laboratories supporting fundamental research in wind technologies, including aerodynamics, aeroacoustics, and material sciences essential in the development of new blade technologies and advanced controls, power electronics, and testing to further refine drivetrain topology.

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


481

Wind power today  

SciTech Connect (OSTI)

This publication highlights initiatives of the US DOE`s Wind Energy Program. 1997 yearly activities are also very briefly summarized. The first article describes a 6-megawatt wind power plant installed in Vermont. Another article summarizes technical advances in wind turbine technology, and describes next-generation utility and small wind turbines in the planning stages. A village power project in Alaska using three 50-kilowatt turbines is described. Very brief summaries of the Federal Wind Energy Program and the National Wind Technology Center are also included in the publication.

NONE

1998-04-01T23:59:59.000Z

482

Wind Power Career Chat  

SciTech Connect (OSTI)

This document will teach students about careers in the wind energy industry. Wind energy, both land-based and offshore, is expected to provide thousands of new jobs in the next several decades. Wind energy companies are growing rapidly to meet America's demand for clean, renewable, and domestic energy. These companies need skilled professionals. Wind power careers will require educated people from a variety of areas. Trained and qualified workers manufacture, construct, operate, and manage wind energy facilities. The nation will also need skilled researchers, scientists, and engineers to plan and develop the next generation of wind energy technologies.

Not Available

2011-01-01T23:59:59.000Z

483

Wind energy information guide  

SciTech Connect (OSTI)

This book is divided into nine chapters. Chapters 1--8 provide background and annotated references on wind energy research, development, and commercialization. Chapter 9 lists additional sources of printed information and relevant organizations. Four indices provide alphabetical access to authors, organizations, computer models and design tools, and subjects. A list of abbreviations and acronyms is also included. Chapter topics include: introduction; economics of using wind energy; wind energy resources; wind turbine design, development, and testing; applications; environmental issues of wind power; institutional issues; and wind energy systems development.

NONE

1996-04-01T23:59:59.000Z

484

Information theoretical characterization of turbulence  

Science Journals Connector (OSTI)

A method of describing turbulence in terms of dynamical connectivity in the wave-number space is proposed. The connectivity is quantified by the information theoretical quantities, i.e., mutual information and cross information flow rate. This method is applied to the analysis of two simple examples of turbulence in one spatial dimension. Although the examples have quite different physical origins, the information structures of the wave-number space turn out to be quite similar: The wave-number space consists of several regions generating information in different ways, and how information flows between these regions reflects the dynamical structure of turbulence.

K. Ikeda and K. Matsumoto

1989-05-08T23:59:59.000Z

485

EA-1726: Kahuku Wind Power, LLC Wind Power Generation Facility...  

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

6: Kahuku Wind Power, LLC Wind Power Generation Facility, O'ahu, HI EA-1726: Kahuku Wind Power, LLC Wind Power Generation Facility, O'ahu, HI May 3, 2010 EA-1726: Final...

486

Women of Wind Energy Honor Wind Program Researchers | Department...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Women of Wind Energy Honor Wind Program Researchers Women of Wind Energy Honor Wind Program Researchers August 1, 2013 - 2:54pm Addthis This is an excerpt from the Second Quarter...

487

Magnetic helicity signature produced by cross-field 2D turbulence  

SciTech Connect (OSTI)

Hybrid numerical simulations of freely decaying 2D turbulence are presented. The background magnetic field is perpendicular to the simulation plane, which eliminates linear kinetic Alfven waves from the system. The normalized magnetic helicity of the initial large-scale fluctuations is zero, while the normalized cross-helicity is not. As the turbulence evolves, it develops nonzero magnetic helicity at smaller scales, in the proton kinetic range. In the quasi-steady state of evolution, the magnetic helicity spectrum has a peak consistent with the solar wind observations.

Markovskii, S. A.; Vasquez, Bernard J. [Space Science Center, Institute for the Study of Earth, Oceans, and Space, and Department of Physics, University of New Hampshire, Durham, NH 03824 (United States)

2013-06-13T23:59:59.000Z

488

Magnetic helicity signature produced by cross-field 2D turbulence  

Science Journals Connector (OSTI)

Hybrid numerical simulations of freely decaying 2D turbulence are presented. The background magnetic field is perpendicular to the simulation plane which eliminates linear kinetic Alfvén waves from the system. The normalized magnetic helicity of the initial large-scale fluctuations is zero while the normalized cross-helicity is not. As the turbulence evolves it develops nonzero magnetic helicity at smaller scales in the proton kinetic range. In the quasi-steady state of evolution the magnetic helicity spectrum has a peak consistent with the solar wind observations.

2013-01-01T23:59:59.000Z

489

Effect of Forced Excitation on Wind Turbine with Dynamic Analysis in Deep Offshore Wind in Addition to Japanese Status of Offshore Projects  

Science Journals Connector (OSTI)

In this paper, we tried to estimate the effect of control method on floating offshore wind turbine. The experiment in the water basin revealed that traditional blade pitch control can amplify the platform pitch oscillation of floating wind turbine. In order to understand the physical phenomenon, we used aeroelastic simulation using GH Bladed. Turbine model is based on the turbine used in wind tunnel test. To simulate the pitching motion of floating platform, we used onshore wind turbine model with inflow with oscillating wind speed that simulates relative wind speed change from wind turbine's fore-aft pitching motion. Two types of control method are used; fixed pitch variable speed control which represents before rated state of large wind turbines and variable pitch variable speed control which represents over rated state of large wind turbines. Comparing the relation between wind speed change and rotor thrust force change of two control methods, we made it clear that traditional blade pitch control method make thrust force change almost the inverse of wind speed increase and decrease. From thrust force inverse to wind speed change, tower pitching motion can be amplified. That is, blade pitch control can induce negative damping on tower pitching motion. As a conclusion pitch control can increase larger blade load although pitch control aims to reduce the blade load.

Mitsumasa Iino; Toshiki Chujo; Makoto Iida; Chuichi Arakawa

2012-01-01T23:59:59.000Z

490

2008 Wind Energy Projects, Wind Powering America (Poster)  

SciTech Connect (OSTI)

The Wind Powering America program produces a poster at the end of every calendar year that depicts new U.S. wind energy projects. The 2008 poster includes the following projects: Stetson Wind Farm in Maine; Dutch Hill Wind Farm in New York; Grand Ridge Wind Energy Center in Illinois; Hooper Bay, Alaska; Forestburg, South Dakota; Elbow Creek Wind Project in Texas; Glacier Wind Farm in Montana; Wray, Colorado; Smoky Hills Wind Farm in Kansas; Forbes Park Wind Project in Massachusetts; Spanish Fork, Utah; Goodland Wind Farm in Indiana; and the Tatanka Wind Energy Project on the border of North Dakota and South Dakota.

Not Available

2009-01-01T23:59:59.000Z

491

LQG control of horizontal wind turbines for blades and tower loads alleviation  

E-Print Network [OSTI]

LQG control of horizontal wind turbines for blades and tower loads alleviation A. Pintea*, N of power produced by two bladed horizontal variable speed wind turbines. The proposed controller ensures oscillations and with the tower bending tendency. Keywords: LQG control, Wind turbines, Multi-objective control

Paris-Sud XI, Université de

492

Wind Power: A Clean and Renewable Supplement to the World's Energy Mix Michael Treadow  

E-Print Network [OSTI]

Wind Power: A Clean and Renewable Supplement to the World's Energy Mix Michael Treadow May 8, 2006 WWS 402d Junior Paper ­ Final Draft Abstract: Wind power harbors the potential to become a key to wind power's growth relate to its remoteness and variability, but neither is an ob- stacle too great

Mauzerall, Denise

493

Coordination of Voltage and Frequency Feedback in Load-Frequency Control Capability of Wind Turbine  

E-Print Network [OSTI]

Coordination of Voltage and Frequency Feedback in Load-Frequency Control Capability of Wind Turbine-Frequency Control (LFC) is gradually shifted to Variable Speed Wind Turbines (VSWTs). In order to equip VSWT@et.aau.dk Abstract--In near future, with high penetration of Wind Energy (WE) in power system, the burden of Load

Silva, Filipe Faria Da

494

Reference value choice of the wind turbine active power with doubly-fed induction generator  

Science Journals Connector (OSTI)

The variable speed wind turbine with doubly-fed induction generator (DFIG) is today widely used concept. This paper presents a control system of the DFIG wind turbine with focus on the control strategies and on active power reference value choice. The ... Keywords: DFIG, dynamic simulation, reference value of active power, wind turbine

J. Smajo; M. Smajo; D. Vukadinovic

2005-11-01T23:59:59.000Z

495

NREL: Wind Research - National Wind Technology Center  

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

Center Center The National Renewable Energy Laboratory's (NREL's) National Wind Technology Center (NWTC), located at the base of the foothills just south of Boulder, Colorado, is the nation's premier wind energy technology research facility. Built in 1993, the center provides an ideal environment for the development of advanced wind energy technologies. The goal of the research conducted at the center is to help industry reduce the cost of energy so that wind can compete with traditional energy sources, providing a clean, renewable alternative for our nation's energy needs. Research at the NWTC is organized under two main categories, Wind Technology Development and Testing and Operations. Illustration of the National Wind Technology Center's organization chart. Fort Felker is listed as the Center Director, with Mike Robinson, Deputy Center Director; Paul Veers, Chief Engineer, and Laura Davis and Dorothy Haldeman beneath him. The Associate Director position is empty. Beneath them is the Wind Technology Research and Development Group Manager, Mike Robinson; the Testing and Operations Group Manager, Dave Simms; and the Offshore Wind and Ocean Power Systems Acting Supervisor, Fort Felker.

496

Wind Rose Bias Correction  

Science Journals Connector (OSTI)

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

Scott Applequist

2012-07-01T23:59:59.000Z

497

GSA Wind Supply Opportunity  

Office of Environmental Management (EM)

Wind Supply Opportunity 1 2 3 Proposed Location * Size: 100-210 MegaWatts *Location: Bureau County, IL *Planned COD: December 2014 or 2015 *Site Control: 17,000 acres *Wind...

498

Scale Models & Wind Turbines  

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

Scale Models and Wind Turbines Grades: 5-8, 9-12 Topics: Wind Energy Owner: Kidwind Project This educational material is brought to you by the U.S. Department of Energy's Office of...