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Sample records for temperature turbulence wind

  1. Predicted impacts of proton temperature anisotropy on solar wind turbulence

    SciTech Connect (OSTI)

    Klein, K. G.; Howes, G. G.

    2015-03-15

    Particle velocity distributions measured in the weakly collisional solar wind are frequently found to be non-Maxwellian, but how these non-Maxwellian distributions impact the physics of plasma turbulence in the solar wind remains unanswered. Using numerical solutions of the linear dispersion relation for a collisionless plasma with a bi-Maxwellian proton velocity distribution, we present a unified framework for the four proton temperature anisotropy instabilities, identifying the associated stable eigenmodes, highlighting the unstable region of wavevector space and presenting the properties of the growing eigenfunctions. Based on physical intuition gained from this framework, we address how the proton temperature anisotropy impacts the nonlinear dynamics of the Alfvénic fluctuations underlying the dominant cascade of energy from large to small scales and how the fluctuations driven by proton temperature anisotropy instabilities interact nonlinearly with each other and with the fluctuations of the large-scale cascade. We find that the nonlinear dynamics of the large-scale cascade is insensitive to the proton temperature anisotropy and that the instability-driven fluctuations are unlikely to cause significant nonlinear evolution of either the instability-driven fluctuations or the turbulent fluctuations of the large-scale cascade.

  2. Supercomputers Capture Turbulence in the Solar Wind

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

    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

  3. Supercomputers Capture Turbulence in the Solar Wind

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

    the solar wind occurring down to electron scales. This is a phenomenon common in fluid dynamics-turbulent energy ... he created tools to filter out the "noise" in the datasets. ...

  4. Turbulence and waves in the solar wind

    SciTech Connect (OSTI)

    Roberts, D.A.; Goldstein, M.L. )

    1991-01-01

    Studies of turbulence and waves in the solar wind is discussed. Consideration is given to the observations and theory concerning the origin and evolution of interplanetary MHD fluctuations and to the observations, theory, and simulations of compressive fluctuations. Particular attention is given to extrapolations to near-sun and polar fields regions. Results obtained on turbulence at comets and magnetic turbulence of low-frequency waves excited by unstable distributions of ions are discussed. 230 refs.

  5. PROTON KINETIC EFFECTS IN VLASOV AND SOLAR WIND TURBULENCE

    SciTech Connect (OSTI)

    Servidio, S.; Valentini, F.; Perrone, D.; Veltri, P.; Osman, K. T.; Chapman, S.; Califano, F.; Matthaeus, W. H.

    2014-02-01

    Kinetic plasma processes are investigated in the framework of solar wind turbulence, employing hybrid Vlasov-Maxwell (HVM) simulations. Statistical analysis of spacecraft observation data relates proton temperature anisotropy T /T {sub ∥} and parallel plasma beta β{sub ∥}, where subscripts refer to the ambient magnetic field direction. Here, this relationship is recovered using an ensemble of HVM simulations. By varying plasma parameters, such as plasma beta and fluctuation level, the simulations explore distinct regions of the parameter space given by T /T {sub ∥} and β{sub ∥}, similar to solar wind sub-datasets. Moreover, both simulation and solar wind data suggest that temperature anisotropy is not only associated with magnetic intermittent events, but also with gradient-type structures in the flow and in the density. This connection between non-Maxwellian kinetic effects and various types of intermittency may be a key point for understanding the complex nature of plasma turbulence.

  6. RELAXATION PROCESSES IN SOLAR WIND TURBULENCE

    SciTech Connect (OSTI)

    Servidio, S.; Carbone, V.; Gurgiolo, C.; Goldstein, M. L.

    2014-07-10

    Based on global conservation principles, magnetohydrodynamic (MHD) relaxation theory predicts the existence of several equilibria, such as the Taylor state or global dynamic alignment. These states are generally viewed as very long-time and large-scale equilibria, which emerge only after the termination of the turbulent cascade. As suggested by hydrodynamics and by recent MHD numerical simulations, relaxation processes can occur during the turbulent cascade that will manifest themselves as local patches of equilibrium-like configurations. Using multi-spacecraft analysis techniques in conjunction with Cluster data, we compute the current density and flow vorticity and for the first time demonstrate that these localized relaxation events are observed in the solar wind. Such events have important consequences for the statistics of plasma turbulence.

  7. On apparent temperature in low-frequency Alfvenic turbulence

    SciTech Connect (OSTI)

    Nariyuki, Yasuhiro

    2012-08-15

    Low-frequency, parallel propagating Alfvenic turbulence in collisionless plasmas is theoretically studied. Alfvenic turbulence is derived as an equilibrium state (Beltrami field) in the magnetohydrodynamic equations with the pressure anisotropy and multi-species of ions. It is shown that the conservation of the total 'apparent temperature' corresponds to the Bernoulli law. A simple model of the radially expanding solar wind including Alfvenic turbulence is also discussed. The conversion of the wave energy in the 'apparent temperature' into the 'real temperature' is facilitated with increasing radial distance.

  8. Dissipation of turbulence in the wake of a wind turbine

    SciTech Connect (OSTI)

    Lundquist, J. K.; Bariteau, L.

    2014-11-06

    The wake of a wind turbine is characterized by increased turbulence and decreased wind speed. Turbines are generally deployed in large groups in wind farms, and so the behaviour of an individual wake as it merges with other wakes and propagates downwind is critical in assessing wind-farm power production. This evolution depends on the rate of turbulence dissipation in the wind-turbine wake, which has not been previously quantified in field-scale measurements. In situ measurements of winds and turbulence dissipation from the wake region of a multi-MW turbine were collected using a tethered lifting system (TLS) carrying a payload of high-rate turbulence probes. Ambient flow measurements were provided from sonic anemometers on a meteorological tower located near the turbine. Good agreement between the tower measurements and the TLS measurements was established for a case without a wind-turbine wake. When an operating wind turbine is located between the tower and the TLS so that the wake propagates to the TLS, the TLS measures dissipation rates one to two orders of magnitude higher in the wake than outside of the wake. These data, collected between two and three rotor diameters D downwind of the turbine, document the significant enhancement of turbulent kinetic energy dissipation rate within the wind-turbine wake. These wake measurements suggest that it may be useful to pursue modelling approaches that account for enhanced dissipation. Furthermore. comparisons of wake and non-wake dissipation rates to mean wind speed, wind-speed variance, and turbulence intensity are presented to facilitate the inclusion of these measurements in wake modelling schemes.

  9. Dissipation of turbulence in the wake of a wind turbine

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

    Lundquist, J. K.; Bariteau, L.

    2014-11-06

    The wake of a wind turbine is characterized by increased turbulence and decreased wind speed. Turbines are generally deployed in large groups in wind farms, and so the behaviour of an individual wake as it merges with other wakes and propagates downwind is critical in assessing wind-farm power production. This evolution depends on the rate of turbulence dissipation in the wind-turbine wake, which has not been previously quantified in field-scale measurements. In situ measurements of winds and turbulence dissipation from the wake region of a multi-MW turbine were collected using a tethered lifting system (TLS) carrying a payload of high-ratemore » turbulence probes. Ambient flow measurements were provided from sonic anemometers on a meteorological tower located near the turbine. Good agreement between the tower measurements and the TLS measurements was established for a case without a wind-turbine wake. When an operating wind turbine is located between the tower and the TLS so that the wake propagates to the TLS, the TLS measures dissipation rates one to two orders of magnitude higher in the wake than outside of the wake. These data, collected between two and three rotor diameters D downwind of the turbine, document the significant enhancement of turbulent kinetic energy dissipation rate within the wind-turbine wake. These wake measurements suggest that it may be useful to pursue modelling approaches that account for enhanced dissipation. Furthermore. comparisons of wake and non-wake dissipation rates to mean wind speed, wind-speed variance, and turbulence intensity are presented to facilitate the inclusion of these measurements in wake modelling schemes.« less

  10. THE TURBULENT CASCADE AND PROTON HEATING IN THE SOLAR WIND DURING SOLAR MINIMUM

    SciTech Connect (OSTI)

    Coburn, Jesse T.; Smith, Charles W.; Vasquez, Bernard J.; Stawarz, Joshua E.; Forman, Miriam A. E-mail: Charles.Smith@unh.edu E-mail: Joshua.Stawarz@Colorado.edu

    2012-08-01

    The recently protracted solar minimum provided years of interplanetary data that were largely absent in any association with observed large-scale transient behavior on the Sun. With large-scale shear at 1 AU generally isolated to corotating interaction regions, it is reasonable to ask whether the solar wind is significantly turbulent at this time. We perform a series of third-moment analyses using data from the Advanced Composition Explorer. We show that the solar wind at 1 AU is just as turbulent as at any other time in the solar cycle. Specifically, the turbulent cascade of energy scales in the same manner proportional to the product of wind speed and temperature. Energy cascade rates during solar minimum average a factor of 2-4 higher than during solar maximum, but we contend that this is likely the result of having a different admixture of high-latitude sources.

  11. Petascale Simulations of Inhomogeneous Alfven Turbulence in the Solar Wind

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

    | Argonne Leadership Computing Facility Petascale Simulations of Inhomogeneous Alfven Turbulence in the Solar Wind PI Name: Jean C Perez PI Email: jeanc.perez@unh.edu Institution: University of New Hampshire Allocation Program: INCITE Allocation Hours at ALCF: 10,000,000 Year: 2012 Research Domain: Physics This project's large-scale numerical simulations of Alfvén wave (AW) turbulence in the outermost atmosphere of the sun will lead to new insights into the basic properties of inhomogeneous

  12. Measurement of turbulent wind velocities using a rotating boom apparatus

    SciTech Connect (OSTI)

    Sandborn, V.A.; Connell, J.R.

    1984-04-01

    The present report covers both the development of a rotating-boom facility and the evaluation of the spectral energy of the turbulence measured relative to the rotating boom. The rotating boom is composed of a helicopter blade driven through a pulley speed reducer by a variable speed motor. The boom is mounted on a semiportable tower that can be raised to provide various ratios of hub height to rotor diameter. The boom can be mounted to rotate in either the vertical or horizontal plane. Probes that measure the three components of turbulence can be mounted at any location along the radius of the boom. Special hot-film sensors measured two components of the turbulence at a point directly in front of the rotating blade. By using the probe rotated 90/sup 0/ about its axis, the third turbulent velocity component was measured. Evaluation of the spectral energy distributions for the three components of velocity indicates a large concentration of energy at the rotational frequency. At frequencies slightly below the rotational frequency, the spectral energy is greatly reduced over that measured for the nonrotating case measurements. Peaks in the energy at frequencies that are multiples of the rotation frequency were also observed. We conclude that the rotating boom apparatus is suitable and ready to be used in experiments for developing and testing sensors for rotational measurement of wind velocity from wind turbine rotors. It also can be used to accurately measure turbulent wind for testing theories of rotationally sampled wind velocity.

  13. Measurements of Wind and Turbulence Profiles with Scanning Doppler Lidar for Wind Energy Applications

    SciTech Connect (OSTI)

    Frehlich, R.; Kelley, N.

    2008-03-01

    High-quality profiles of mean and turbulent statistics of the wind field upstream of a wind farm can be produced using a scanning Doppler lidar. Careful corrections for the spatial filtering of the wind field by the lidar pulse produce turbulence estimates equivalent to point sensors but with the added advantage of a larger sampling volume to increase the statistical accuracy of the estimates. For a well-designed lidar system, this permits accurate estimates of the key turbulent statistics over various subdomains and with sufficiently short observation times to monitor rapid changes in conditions. These features may be ideally suited for optimal operation of wind farms and also for improved resource assessment of potential sites.

  14. RECONNECTION OUTFLOW GENERATED TURBULENCE IN THE SOLAR WIND

    SciTech Connect (OSTI)

    Vrs, Z.; Sasunov, Y. L.; Zaqarashvili, T. V.; Khodachenko, M.; Semenov, V. S.; Bruno, R.

    2014-12-10

    Petschek-type time-dependent reconnection (TDR) and quasi-stationary reconnection (QSR) models are considered to understand reconnection outflow structures and the generation of local turbulence in the solar wind. Comparing TDR/QSR model predictions of the outflow structures with actual measurements shows that both models can explain the data equally well. It is demonstrated that the outflows can often generate more or less spatially extended turbulent boundary layers. The structure of a unique extended reconnection outflow is investigated in detail. The analysis of spectral scalings and spectral break locations shows that reconnection can change the local field and plasma conditions which may support different local turbulent dissipation mechanisms at their characteristic wavenumbers.

  15. Three-fluid, three-dimensional magnetohydrodynamic solar wind model with eddy viscosity and turbulent resistivity

    SciTech Connect (OSTI)

    Usmanov, Arcadi V.; Matthaeus, William H.; Goldstein, Melvyn L.

    2014-06-10

    We have developed a three-fluid, three-dimensional magnetohydrodynamic solar wind model that incorporates turbulence transport, eddy viscosity, turbulent resistivity, and turbulent heating. The solar wind plasma is described as a system of co-moving solar wind protons, electrons, and interstellar pickup protons, with separate energy equations for each species. Numerical steady-state solutions of Reynolds-averaged solar wind equations coupled with turbulence transport equations for turbulence energy, cross helicity, and correlation length are obtained by the time relaxation method in the corotating with the Sun frame of reference in the region from 0.3 to 100 AU (but still inside the termination shock). The model equations include the effects of electron heat conduction, Coulomb collisions, photoionization of interstellar hydrogen atoms and their charge exchange with the solar wind protons, turbulence energy generation by pickup protons, and turbulent heating of solar wind protons and electrons. The turbulence transport model is based on the Reynolds decomposition and turbulence phenomenologies that describe the conversion of fluctuation energy into heat due to a turbulent cascade. In addition to using separate energy equations for the solar wind protons and electrons, a significant improvement over our previous work is that the turbulence model now uses an eddy viscosity approximation for the Reynolds stress tensor and the mean turbulent electric field. The approximation allows the turbulence model to account for driving of turbulence by large-scale velocity gradients. Using either a dipole approximation for the solar magnetic field or synoptic solar magnetograms from the Wilcox Solar Observatory for assigning boundary conditions at the coronal base, we apply the model to study the global structure of the solar wind and its three-dimensional properties, including embedded turbulence, heating, and acceleration throughout the heliosphere. The model results are

  16. Turbulent electron transport in edge pedestal by electron temperature gradient turbulence

    SciTech Connect (OSTI)

    Singh, R.; Institute for Plasma Research, Bhat Gandhinagar, Gujarat 2382 428 ; Jhang, Hogun; Diamond, P. H.; CMTFO and CASS, University of California, San Diego 92093-0424, California

    2013-11-15

    We present a model for turbulent electron thermal transport at the edge pedestal in high (H)-mode plasmas based on electron temperature gradient (ETG) turbulence. A quasi-linear analysis of electrostatic toroidal ETG modes shows that both turbulent electron thermal diffusivity and hyper-resistivity exhibits the Ohkawa scaling in which the radial correlation length of turbulence becomes the order of electron skin depth. Combination of the Ohkawa scales and the plasma current dependence results in a novel confinement scaling inside the pedestal region. It is also shown that ETG turbulence induces a thermoelectric pinch, which may accelerate the density pedestal formation.

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

    SciTech Connect (OSTI)

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

    2014-04-01

    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.

  18. Comparison between kinetic-ballooning-mode-driven turbulence and ion-temperature-gradient-driven turbulence

    SciTech Connect (OSTI)

    Maeyama, S. Nakata, M.; Miyato, N.; Yagi, M.; Ishizawa, A.; Watanabe, T.-H.; Idomura, Y.

    2014-05-15

    Electromagnetic turbulence driven by kinetic ballooning modes (KBMs) in high-? plasma is investigated based on the local gyrokinetic model. Analysis of turbulent fluxes, norms, and phases of fluctuations shows that KBM turbulence gives narrower spectra and smaller phase factors than those in ion-temperature-gradient (ITG)-driven turbulence. This leads to the smaller transport fluxes in KBM turbulence than those in ITG turbulence even when they have similar linear growth rates. From the analysis of the entropy balance relation, it is found that the entropy transfer from ions to electrons through the field-particle interactions mainly drives electron perturbations, which creates radial twisted modes by rapid parallel motions of electrons in a sheared magnetic geometry. The nonlinear coupling between the dominant unstable mode and its twisted modes is important for the saturation of KBM turbulence, in contrast to the importance of zonal flow shearing in ITG turbulence. The coupling depends on the flux-tube domain with the one-poloidal-turn parallel length and on the torus periodicity constraint.

  19. Turbulence loads on the Howden 26-m-diameter wind turbine

    SciTech Connect (OSTI)

    Madsen, P.H.; Hock, S.M.; Hausfeld, T.E.

    1987-11-01

    Conducted in Palm Springs, California, a joint effort between SERI and James Howden and Company involved a comprehensive test program on the 330-kW Howden wind turbine with a three-bladed, fixed-hub rotor 26 m in diameter. Part of the measurement analysis is to quantify the turbulence loads during the steady-state production modes of operation. Assuming wind turbulence to be the cause of the random loads, the turbulence loads in terms of blade root-bending moments have been determined empirically by isolating the random or nonperiodic part of the load signals using azimuthal averaging. Standard deviations as functions of wind speed, as well as power spectra of the loads, are presented. The measured turbulence loads are compared to a recently developed model for turbulence loading of wind turbines. The model works in the frequency domain and uses the standard engineering representation of turbulence in terms of a coherence function and a wind-power spectrum at a fixed point in space. The turbulence load model accounts for the dominant mode of vibration for the load in question and is intended to be simple enough to be used for a preliminary load estimate for practical design purposes.

  20. Quantifying the Effect of Lidar Turbulence Error on Wind Power Prediction

    SciTech Connect (OSTI)

    Newman, Jennifer F.; Clifton, Andrew

    2016-01-01

    Currently, cup anemometers on meteorological towers are used to measure wind speeds and turbulence intensity to make decisions about wind turbine class and site suitability; however, as modern turbine hub heights increase and wind energy expands to complex and remote sites, it becomes more difficult and costly to install meteorological towers at potential sites. As a result, remote-sensing devices (e.g., lidars) are now commonly used by wind farm managers and researchers to estimate the flow field at heights spanned by a turbine. Although lidars can accurately estimate mean wind speeds and wind directions, there is still a large amount of uncertainty surrounding the measurement of turbulence using these devices. Errors in lidar turbulence estimates are caused by a variety of factors, including instrument noise, volume averaging, and variance contamination, in which the magnitude of these factors is highly dependent on measurement height and atmospheric stability. As turbulence has a large impact on wind power production, errors in turbulence measurements will translate into errors in wind power prediction. The impact of using lidars rather than cup anemometers for wind power prediction must be understood if lidars are to be considered a viable alternative to cup anemometers.In this poster, the sensitivity of power prediction error to typical lidar turbulence measurement errors is assessed. Turbulence estimates from a vertically profiling WINDCUBE v2 lidar are compared to high-resolution sonic anemometer measurements at field sites in Oklahoma and Colorado to determine the degree of lidar turbulence error that can be expected under different atmospheric conditions. These errors are then incorporated into a power prediction model to estimate the sensitivity of power prediction error to turbulence measurement error. Power prediction models, including the standard binning method and a random forest method, were developed using data from the aeroelastic simulator FAST

  1. Turbulent kinetics of a large wind farm and their impact in the neutral boundary layer

    SciTech Connect (OSTI)

    Na, Ji Sung; Koo, Eunmo; Munoz-Esparza, Domingo; Jin, Emilia Kyung; Linn, Rodman; Lee, Joon Sang

    2015-12-28

    High-resolution large-eddy simulation of the flow over a large wind farm (64 wind turbines) is performed using the HIGRAD/FIRETEC-WindBlade model, which is a high-performance computing wind turbine–atmosphere interaction model that uses the Lagrangian actuator line method to represent rotating turbine blades. These high-resolution large-eddy simulation results are used to parameterize the thrust and power coefficients that contain information about turbine interference effects within the wind farm. Those coefficients are then incorporated into the WRF (Weather Research and Forecasting) model in order to evaluate interference effects in larger-scale models. In the high-resolution WindBlade wind farm simulation, insufficient distance between turbines creates the interference between turbines, including significant vertical variations in momentum and turbulent intensity. The characteristics of the wake are further investigated by analyzing the distribution of the vorticity and turbulent intensity. Quadrant analysis in the turbine and post-turbine areas reveals that the ejection motion induced by the presence of the wind turbines is dominant compared to that in the other quadrants, indicating that the sweep motion is increased at the location where strong wake recovery occurs. Regional-scale WRF simulations reveal that although the turbulent mixing induced by the wind farm is partly diffused to the upper region, there is no significant change in the boundary layer depth. The velocity deficit does not appear to be very sensitive to the local distribution of turbine coefficients. However, differences of about 5% on parameterized turbulent kinetic energy were found depending on the turbine coefficient distribution. Furthermore, turbine coefficients that consider interference in the wind farm should be used in wind farm parameterization for larger-scale models to better describe sub-grid scale turbulent processes.

  2. Turbulent kinetics of a large wind farm and their impact in the neutral boundary layer

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

    Na, Ji Sung; Koo, Eunmo; Munoz-Esparza, Domingo; Jin, Emilia Kyung; Linn, Rodman; Lee, Joon Sang

    2015-12-28

    High-resolution large-eddy simulation of the flow over a large wind farm (64 wind turbines) is performed using the HIGRAD/FIRETEC-WindBlade model, which is a high-performance computing wind turbine–atmosphere interaction model that uses the Lagrangian actuator line method to represent rotating turbine blades. These high-resolution large-eddy simulation results are used to parameterize the thrust and power coefficients that contain information about turbine interference effects within the wind farm. Those coefficients are then incorporated into the WRF (Weather Research and Forecasting) model in order to evaluate interference effects in larger-scale models. In the high-resolution WindBlade wind farm simulation, insufficient distance between turbines createsmore » the interference between turbines, including significant vertical variations in momentum and turbulent intensity. The characteristics of the wake are further investigated by analyzing the distribution of the vorticity and turbulent intensity. Quadrant analysis in the turbine and post-turbine areas reveals that the ejection motion induced by the presence of the wind turbines is dominant compared to that in the other quadrants, indicating that the sweep motion is increased at the location where strong wake recovery occurs. Regional-scale WRF simulations reveal that although the turbulent mixing induced by the wind farm is partly diffused to the upper region, there is no significant change in the boundary layer depth. The velocity deficit does not appear to be very sensitive to the local distribution of turbine coefficients. However, differences of about 5% on parameterized turbulent kinetic energy were found depending on the turbine coefficient distribution. Furthermore, turbine coefficients that consider interference in the wind farm should be used in wind farm parameterization for larger-scale models to better describe sub-grid scale turbulent processes.« less

  3. Analyzing Effects of Turbulence on Power Generation Using Wind Plant Monitoring Data: Preprint

    SciTech Connect (OSTI)

    Zhang, J.; Chowdhury, S.; Hodge, B. M.

    2014-01-01

    In this paper, a methodology is developed to analyze how ambient and wake turbulence affects the power generation of a single wind turbine within an array of turbines. Using monitoring data from a wind power plant, we selected two sets of wind and power data for turbines on the edge of the wind plant that resemble (i) an out-of-wake scenario (i.e., when the turbine directly faces incoming winds) and (ii) an in-wake scenario (i.e., when the turbine is under the wake of other turbines). For each set of data, two surrogate models were then developed to represent the turbine power generation (i) as a function of the wind speed; and (ii) as a function of the wind speed and turbulence intensity. Support vector regression was adopted for the development of the surrogate models. Three types of uncertainties in the turbine power generation were also investigated: (i) the uncertainty in power generation with respect to the published/reported power curve, (ii) the uncertainty in power generation with respect to the estimated power response that accounts for only mean wind speed; and (iii) the uncertainty in power generation with respect to the estimated power response that accounts for both mean wind speed and turbulence intensity. Results show that (i) under the same wind conditions, the turbine generates different power between the in-wake and out-of-wake scenarios, (ii) a turbine generally produces more power under the in-wake scenario than under the out-of-wake scenario, (iii) the power generation is sensitive to turbulence intensity even when the wind speed is greater than the turbine rated speed, and (iv) there is relatively more uncertainty in the power generation under the in-wake scenario than under the out-of-wake scenario.

  4. The turbulent cascade and proton heating in the solar wind during solar minimum

    SciTech Connect (OSTI)

    Coburn, Jesse T.; Smith, Charles W.; Vasquez, Bernard J.; Stawarz, Joshua E.; Forman, Miriam A.

    2013-06-13

    Solar wind measurements at 1 AU during the recent solar minimum and previous studies of solar maximum provide an opportunity to study the effects of the changing solar cycle on in situ heating. Our interest is to compare the levels of activity associated with turbulence and proton heating. Large-scale shears in the flow caused by transient activity are a source that drives turbulence that heats the solar wind, but as the solar cycle progresses the dynamics that drive the turbulence and heat the medium are likely to change. The application of third-moment theory to Advanced Composition Explorer (ACE) data gives the turbulent energy cascade rate which is not seen to vary with the solar cycle. Likewise, an empirical heating rate shows no significan changes in proton heating over the cycle.

  5. Electron geodesic acoustic modes in electron temperature gradient mode turbulence

    SciTech Connect (OSTI)

    Anderson, Johan; Nordman, Hans [Department of Earth and Space Sciences, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden); Singh, Raghvendra; Kaw, Predhiman [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India)

    2012-08-15

    In this work, the first demonstration of an electron branch of the geodesic acoustic mode (el-GAM) driven by electron temperature gradient (ETG) modes is presented. The work is based on a fluid description of the ETG mode retaining non-adiabatic ions and the dispersion relation for el-GAMs driven nonlinearly by ETG modes is derived. A new saturation mechanism for ETG turbulence through the interaction with el-GAMs is found, resulting in a significantly enhanced ETG turbulence saturation level compared to the mixing length estimate.

  6. Petascale Simulations of Inhomogeneous Alfven Turbulence in the Solar Wind

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

    | Argonne Leadership Computing Facility 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

  7. THE INFLUENCE OF INTERMITTENCY ON THE SPECTRAL ANISOTROPY OF SOLAR WIND TURBULENCE

    SciTech Connect (OSTI)

    Wang, Xin; Tu, Chuanyi; He, Jiansen; Wang, Linghua; Marsch, Eckart

    2014-03-01

    The relation between the intermittency and the anisotropy of the power spectrum in the solar wind turbulence is studied by applying the wavelet technique to the magnetic field and flow velocity data measured by the WIND spacecraft. It is found that when the intermittency is removed from the turbulence, the spectral indices of the power spectra of the field and velocity turn out to be independent of the angle ?{sub RB} between the direction of the local scale-dependent background magnetic field and the heliocentric direction. The spectral index becomes 1.63 0.02 for magnetic field fluctuations and 1.56 0.02 for velocity fluctuations. These results may suggest that the recently found spectral anisotropy of solar wind power spectra in the inertial range could result from turbulence intermittency. As a consequence, a new concept is here proposed of an intermittency-associated sub-range of the inertial domain adjacent to the dissipation range. Since spectral anisotropy was previously explained as evidence for the presence of a ''critical balance'' type turbulent cascade, and also for the existence of kinetic Alfvn waves, this new finding may stimulate fresh thoughts on how to analyze and interpret solar wind turbulence and the associated heating.

  8. ENSEMBLE SIMULATIONS OF PROTON HEATING IN THE SOLAR WIND VIA TURBULENCE AND ION CYCLOTRON RESONANCE

    SciTech Connect (OSTI)

    Cranmer, Steven R.

    2014-07-01

    Protons in the solar corona and heliosphere exhibit anisotropic velocity distributions, violation of magnetic moment conservation, and a general lack of thermal equilibrium with the other particle species. There is no agreement about the identity of the physical processes that energize non-Maxwellian protons in the solar wind, but a traditional favorite has been the dissipation of ion cyclotron resonant Alfvén waves. This paper presents kinetic models of how ion cyclotron waves heat protons on their journey from the corona to interplanetary space. It also derives a wide range of new solutions for the relevant dispersion relations, marginal stability boundaries, and nonresonant velocity-space diffusion rates. A phenomenological model containing both cyclotron damping and turbulent cascade is constructed to explain the suppression of proton heating at low alpha-proton differential flow speeds. These effects are implemented in a large-scale model of proton thermal evolution from the corona to 1 AU. A Monte Carlo ensemble of realistic wind speeds, densities, magnetic field strengths, and heating rates produces a filled region of parameter space (in a plane described by the parallel plasma beta and the proton temperature anisotropy ratio) similar to what is measured. The high-beta edges of this filled region are governed by plasma instabilities and strong heating rates. The low-beta edges correspond to weaker proton heating and a range of relative contributions from cyclotron resonance. On balance, the models are consistent with other studies that find only a small fraction of the turbulent power spectrum needs to consist of ion cyclotron waves.

  9. Short wavelength ion temperature gradient turbulence

    SciTech Connect (OSTI)

    Chowdhury, J.; Ganesh, R. [Institute for Plasma Research, Bhat, Gandhinagar (India); Brunner, S.; Lapillonne, X.; Villard, L. [CRPP, Association EURATOM-Confederation Suisse, EPFL, 1015 Lausanne (Switzerland); Jenko, F. [Max-Planck-Institut fuer Plasmaphysik Boltzmannstr. 2, D-85748 Garching (Germany)

    2012-10-15

    The ion temperature gradient (ITG) mode in the high wavenumber regime (k{sub y}{rho}{sub s}>1), referred to as short wavelength ion temperature gradient mode (SWITG) is studied using the nonlinear gyrokinetic electromagnetic code GENE. It is shown that, although the SWITG mode may be linearly more unstable than the standard long wavelength (k{sub y}{rho}{sub s}<1) ITG mode, nonlinearly its contribution to the total thermal ion heat transport is found to be low. We interpret this as resulting from an increased zonal flow shearing effect on the SWITG mode suppression.

  10. Covariance statistics of turbulence velocity components for wind-energy-conversion system design-homogeneous, isotropic case

    SciTech Connect (OSTI)

    Fichtl, G.H.

    1983-09-01

    When designing a wind energy converison system (WECS), it may be necessary to take into account the distribution of wind across the disc of rotation. The specific engineering applications include structural strength, fatigue, and control. This wind distribution consists of two parts, namely that associated with the mean wind profile and that associated with the turbulence velocity fluctuation field. The work reported herein is aimed at the latter, namely the distribution of turbulence velocity fluctuations across the WECS disk of rotation. A theory is developed for the two-time covariance matrix for turbulence velocity vector components for wind energy conversion system (WECS) design. The theory is developed for homogeneous and iotropic turbulance with the assumption that Taylor's hypothesis is valid. The Eulerian turbulence velocity vector field is expanded about the hub of the WECS. Formulae are developed for the turbulence velocity vector component covariance matrix following the WECS blade elements. It is shown that upon specification of the turbulence energy spectrum function and the WECS rotation rate, the two-point, two-time covariance matrix of the turbulent flow relative to the WECS bladed elements is determined. This covariance matrix is represented as the sum of nonstationary and stationary contributions. Generalized power spectral methods are used to obtain two-point, double frequency power spectral density functions for the turbulent flow following the blade elements. The Dryden turbulence model is used to demonstrate the theory. A discussion of linear system response analysis is provided to show how the double frequency turbulence spectra might be used to calculate response spectra of a WECS to turbulent flow. Finally the spectrum of the component of turbulence normal to the WECS disc of rotation, following the blade elements, is compared with experimental results.

  11. Coherent structures in ion temperature gradient turbulence-zonal flow

    SciTech Connect (OSTI)

    Singh, Rameswar; Singh, R.; Kaw, P.; Grcan, . D.; Diamond, P. H.

    2014-10-15

    Nonlinear stationary structure formation in the coupled ion temperature gradient (ITG)-zonal flow system is investigated. The ITG turbulence is described by a wave-kinetic equation for the action density of the ITG mode, and the longer scale zonal mode is described by a dynamic equation for the m?=?n?=?0 component of the potential. Two populations of trapped and untrapped drift wave trajectories are shown to exist in a moving frame of reference. This novel effect leads to the formation of nonlinear stationary structures. It is shown that the ITG turbulence can self-consistently sustain coherent, radially propagating modulation envelope structures such as solitons, shocks, and nonlinear wave trains.

  12. Reconnection and electron temperature anisotropy in sub-proton scale plasma turbulence

    SciTech Connect (OSTI)

    Haynes, C. T.; Burgess, D.; Camporeale, E.

    2014-03-01

    Knowledge of turbulent behavior at sub-proton scales in magnetized plasmas is important for a full understanding of the energetics of astrophysical flows such as the solar wind. We study the formation of electron temperature anisotropy due to reconnection in the turbulent decay of sub-proton scale fluctuations using two-dimensional, particle-in-cell plasma simulations with a realistic electron-proton mass ratio and a guide field perpendicular to the simulation plane. A power spectrum fluctuation with approximately power-law form is created down to scales of the order of the electron gyroradius. We identify the signatures of collisionless reconnection at sites of X-point field geometry in the dynamic magnetic field topology, which gradually relaxes in complexity. The reconnection sites are generally associated with regions of strong parallel electron temperature anisotropy. The evolving topology of magnetic field lines connected to a reconnection site allows for the spatial mixing of electrons accelerated at multiple, spatially separated reconnection regions. This leads to the formation of multi-peaked velocity distribution functions with strong parallel temperature anisotropy. In a three-dimensional system that can support the appropriate wave vectors, the multi-peaked distribution functions would be expected to be unstable to kinetic instabilities, contributing to dissipation. The proposed mechanism of anisotropy formation is also relevant to space and astrophysical systems where the evolution of the plasma is constrained by linear temperature anisotropy instability thresholds. The presence of reconnection sites leads to electron energy gain, nonlocal velocity space mixing, and the formation of strong temperature anisotropy; this is evidence of an important role for reconnection in the dissipation of turbulent fluctuations.

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

    SciTech Connect (OSTI)

    Gamayunov, Konstantin V.; Zhang Ming; Rassoul, Hamid K.; Pogorelov, Nikolai V.; Heerikhuisen, Jacob

    2012-09-20

    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

  14. Nonlinear and linear timescales near kinetic scales in solar wind turbulence

    SciTech Connect (OSTI)

    Matthaeus, W. H.; Wan, M.; Shay, M. A.; Oughton, S.; Osman, K. T.; Chapman, S. C.; Servidio, S.; Valentini, F.; Gary, S. P.; Roytershteyn, V.; Karimabadi, H.

    2014-08-01

    The application of linear kinetic treatments to plasma waves, damping, and instability requires favorable inequalities between the associated linear timescales and timescales for nonlinear (e.g., turbulence) evolution. In the solar wind these two types of timescales may be directly compared using standard Kolmogorov-style analysis and observational data. The estimated local (in scale) nonlinear magnetohydrodynamic cascade times, evaluated as relevant kinetic scales are approached, remain slower than the cyclotron period, but comparable to or faster than the typical timescales of instabilities, anisotropic waves, and wave damping. The variation with length scale of the turbulence timescales is supported by observations and simulations. On this basis the use of linear theory—which assumes constant parameters to calculate the associated kinetic rates—may be questioned. It is suggested that the product of proton gyrofrequency and nonlinear time at the ion gyroscales provides a simple measure of turbulence influence on proton kinetic behavior.

  15. THE SLOW-MODE NATURE OF COMPRESSIBLE WAVE POWER IN SOLAR WIND TURBULENCE

    SciTech Connect (OSTI)

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

    2012-07-01

    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{sub ||}) between proton density fluctuations {delta}n and the field-aligned (compressible) component of the magnetic field {delta}B{sub ||} is negative and close to -1. The typical dependence of C({delta}n, {delta}B{sub ||}) on the ion plasma beta {beta}{sub 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.

  16. Coherent structures and turbulent spectrum in solar wind plasmas

    SciTech Connect (OSTI)

    Sharma, R. P.; Yadav, N.; Kumari, Anju

    2013-08-15

    The present paper investigates the localization of a uniform plane kinetic Alfvn wave (KAW) due to the coupling with the density/magnetic field fluctuations associated with a magnetosonic wave propagating in the transverse direction, i.e., perpendicular to the background magnetic field. To gain the physical insight into this evolution, a simplified analytical model based on the Mathieu equation has also been studied. Numerical method has also been used to analyse the evolution of KAW. The magnetic fluctuation spectrum follows Kolmogorovian scaling above the proton gyroradius scalelength, which is regarded as the inertial range. Below this scale, a steepened spectrum has been obtained in the dispersive range with power law index ??2.5, which continues up to the dissipation range. Our results reveal that the proposed mechanism may be an interesting physical mechanism for transferring the energy from larger lengthscales to smaller lengthscales in the solar wind plasmas. Relevance of the present study with Cluster spacecraft observations has also been discussed.

  17. Nonlinear interaction of proton whistler with kinetic Alfvn wave to study solar wind turbulence

    SciTech Connect (OSTI)

    Goyal, R.; Sharma, R. P.; Goldstein, M. L.; Dwivedi, N. K.

    2013-12-15

    This paper presents the nonlinear interaction between small but finite amplitude kinetic Alfvn 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.

  18. Evolution of turbulence in the expanding solar wind, a numerical study

    SciTech Connect (OSTI)

    Dong, Yue; Grappin, Roland; Verdini, Andrea E-mail: verdini@arcetri.astro.it

    2014-10-01

    We study the evolution of turbulence in the solar wind by solving numerically the full three-dimensional (3D) magnetohydrodynamic (MHD) equations embedded in a radial mean wind. The corresponding equations (expanding box model or EBM) have been considered earlier but never integrated in 3D simulations. Here, we follow the development of turbulence from 0.2 AU up to about 1.5 AU. Starting with isotropic spectra scaling as k {sup –1}, we observe a steepening toward a k {sup –5/3} scaling in the middle of the wave number range and formation of spectral anisotropies. The advection of a plasma volume by the expanding solar wind causes a non-trivial stretching of the volume in directions transverse to radial and the selective decay of the components of velocity and magnetic fluctuations. These two effects combine to yield the following results. (1) Spectral anisotropy: gyrotropy is broken, and the radial wave vectors have most of the power. (2) Coherent structures: radial streams emerge that resemble the observed microjets. (3) Energy spectra per component: they show an ordering in good agreement with the one observed in the solar wind at 1 AU. The latter point includes a global dominance of the magnetic energy over kinetic energy in the inertial and f {sup –1} range and a dominance of the perpendicular-to-the-radial components over the radial components in the inertial range. We conclude that many of the above properties are the result of evolution during transport in the heliosphere, and not just the remnant of the initial turbulence close to the Sun.

  19. WHERE DOES FLUID-LIKE TURBULENCE BREAK DOWN IN THE SOLAR WIND?

    SciTech Connect (OSTI)

    Perri, S.; Carbone, V.; Veltri, P.

    2010-12-10

    Power spectra of the magnetic field in solar wind display a Kolmogorov law f {sup -5/3} at intermediate range of frequencies f, say within the inertial range. Two spectral breaks are also observed: one separating the inertial range from an f {sup -1} spectrum at lower frequencies, and another one between the inertial range and an f {sup -7/3} spectrum at higher frequencies. The breaking of fluid-like turbulence at high frequencies has been attributed to either the occurrence of kinetic Alfven wave fluctuations above the ion-cyclotron frequency or to whistler turbulence above the frequency corresponding to the proton gyroradius. Using solar wind data, we show that the observed high-frequency spectral break seems to be independent of the distance from the Sun, and then of both the ion-cyclotron frequency and the proton gyroradius. We suppose that the observed high-frequency break could be either caused by a combination of different physical processes or associated with a remnant signature of coronal turbulence.

  20. Pitch angle and velocity diffusions of newborn ions by turbulence in the solar wind

    SciTech Connect (OSTI)

    Ziebell, L.F.; Yoon, P.H. )

    1990-12-01

    The present study is dedicated to the analysis of dynamical processes relevant to the interaction of newborn ions with turbulence in the solar wind, when the level of turbulence is moderately low so that quasi-linear theory is applicable. It is assumed that the low-frequency turbulence is at saturation level and not affected by the newborn ions. In order to follow the time evolution of the ion distribution, the quasi-linear diffusion equation is derived and numerically solved, starting from a ring-beam initial distribution. A simplified treatment of the resonance broadening effect is included in the diffusion equation, and its role in the pickup process is discussed. Two different configurations of wave polarization and direction of propagation are considered, using model turbulence spectra. The conditions that lead either to the formation of anisotropic shells as a long-duration transient state or to rapid isotropization of the ion pitch angle distribution are discussed, as well as the conditions leading to significant acceleration of the ions.

  1. KINETIC PLASMA TURBULENCE IN THE FAST SOLAR WIND MEASURED BY CLUSTER

    SciTech Connect (OSTI)

    Roberts, O. W.; Li, X.; Li, B.

    2013-05-20

    The k-filtering technique and wave polarization analysis are applied to Cluster magnetic field data to study plasma turbulence at the scale of the ion gyroradius in the fast solar wind. Waves are found propagating in directions nearly perpendicular to the background magnetic field at such scales. The frequencies of these waves in the solar wind frame are much smaller than the proton gyrofrequency. After the wavevector k is determined at each spacecraft frequency f{sub sc}, wave polarization property is analyzed in the plane perpendicular to k. Magnetic fluctuations have {delta}B > {delta}B{sub Parallel-To} (here the Parallel-To and refer to the background magnetic field B{sub 0}). The wave magnetic field has right-handed polarization at propagation angles {theta}{sub kB} < 90 Degree-Sign and >90 Degree-Sign . The magnetic field in the plane perpendicular to B{sub 0}, however, has no clear sense of a dominant polarization but local rotations. We discuss the merits and limitations of linear kinetic Alfven waves (KAWs) and coherent Alfven vortices in the interpretation of the data. We suggest that the fast solar wind turbulence may be populated with KAWs, small-scale current sheets, and Alfven vortices at ion kinetic scales.

  2. Ion temperature gradient driven turbulence with strong trapped...

    Office of Scientific and Technical Information (OSTI)

    driven turbulence with strong trapped ion resonance is presented. The role of trapped ion granulations, clusters of trapped ions correlated by precession resonance, is the focus. ...

  3. ON QUIET-TIME SOLAR WIND ELECTRON DISTRIBUTIONS IN DYNAMICAL EQUILIBRIUM WITH LANGMUIR TURBULENCE

    SciTech Connect (OSTI)

    Zaheer, S.; Yoon, P. H.

    2013-10-01

    A recent series of papers put forth a self-consistent theory of an asymptotically steady-state electron distribution function and Langmuir turbulence intensity. The theory was developed in terms of the ? distribution which features Maxwellian low-energy electrons and a non-Maxwellian energetic power-law tail component. The present paper discusses a generalized ? distribution that features a Davydov-Druyvesteyn type of core component and an energetic power-law tail component. The physical motivation for such a generalization is so that the model may reflect the influence of low-energy electrons interacting with low-frequency kinetic Alfvnic turbulence as well as with high-frequency Langmuir turbulence. It is shown that such a solution and the accompanying Langmuir wave spectrum rigorously satisfy the balance requirement between the spontaneous and induced emission processes in both the particle and wave kinetic equations, and approximately satisfy the similar balance requirement between the spontaneous and induced scattering processes, which are nonlinear. In spite of the low velocity modification of the electron distribution function, it is shown that the resulting asymptotic velocity power-law index ?, where f{sub e} ? v {sup ?} is close to the average index observed during the quiet-time solar wind condition, i.e., ? ? O(6.5) whereas ?{sub average} ? 6.69, according to observation.

  4. Temperature and species-concentration measurements in turbulent flames by the CARS technique

    SciTech Connect (OSTI)

    Goss, L.P.; Schreiber, P.W.; Switzer, G.L.; Trump, D.D.

    1983-09-01

    Simultaneous temperature and N/sub 2/-concentration data have been obtained employing a 10-Hz coherent anti-stokes Raman spectroscopy system on two propane-air turbulent-jet diffusion flames with Reynolds numbers of 2000 and 6000. Average values, probability density functions, and correlation plots show reasonable trends for both centerline and radial profiles of the turbulent flames.

  5. High-Temperature Motor Windings for Downhole Pumps Used in Geothermal...

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

    Temperature Motor Windings for Downhole Pumps Used in Geothermal Energy Production High-Temperature Motor Windings for Downhole Pumps Used in Geothermal Energy Production Project ...

  6. A Case Study of the Weather Research and Forecasting Model Applied to the Joint Urban 2003 Tracer Field Experiment. Part 1. Wind and Turbulence

    SciTech Connect (OSTI)

    Nelson, Matthew A.; Brown, Michael J.; Halverson, Scot A.; Bieringer, Paul E.; Annunzio, Andrew; Bieberbach, George; Meech, Scott

    2015-09-25

    We found that numerical-weather-prediction models are often used to supply the mean wind and turbulence fields for atmospheric transport and dispersion plume models as they provide dense horizontally- and vertically-resolved geographic coverage in comparison to typically sparse monitoring networks. Here, the Weather Research and Forecasting (WRF) model was run over the month-long period of the Joint Urban 2003 field campaign conducted in Oklahoma City and the simulated fields important to transport and dispersion models were compared to measurements from a number of sodars, tower-based sonic anemometers, and balloon soundings located in the greater metropolitan area. Time histories of computed wind speed, wind direction, turbulent kinetic energy (e), friction velocity (u* ), and reciprocal Obukhov length (1 / L) were compared to measurements over the 1-month field campaign. Vertical profiles of wind speed, potential temperature (θ ), and e were compared during short intensive operating periods. The WRF model was typically able to replicate the measured diurnal variation of the wind fields, but with an average absolute wind direction and speed difference of 35° and 1.9 m s-1 , respectively. Then, using the Mellor-Yamada-Janjic (MYJ) surface-layer scheme, the WRF model was found to generally underpredict surface-layer TKE but overpredict u* that was observed above a suburban region of Oklahoma City. The TKE-threshold method used by the WRF model’s MYJ surface-layer scheme to compute the boundary-layer height (h) consistently overestimated h derived from a θ gradient method whether using observed or modelled θ profiles.

  7. MHD turbulence model for global simulations of the solar wind and SEP acceleration

    SciTech Connect (OSTI)

    Sokolov, Igor V.; Roussev, Ilia I.

    2008-08-25

    The aim of the present work is to unify the various transport equations for turbulent waves that are used in different areas of space physics. We mostly focus on the magnetohydrodynamic (MHD) turbulence, in particular the Alfvenic turbulence.

  8. ON THE LOW-FREQUENCY BOUNDARY OF SUN-GENERATED MAGNETOHYDRODYNAMIC TURBULENCE IN THE SLOW SOLAR WIND

    SciTech Connect (OSTI)

    Shergelashvili, Bidzina M.; Fichtner, Horst

    2012-06-20

    New aspects of the slow solar wind turbulent heating and acceleration are investigated. A physical meaning of the lower boundary of the Alfven wave turbulent spectra in the solar atmosphere and the solar wind is studied and the significance of this natural parameter is demonstrated. Via an analytical and quantitative treatment of the problem we show that a truncation of the wave spectra from the lower frequency side, which is a consequence of the solar magnetic field structure and its cyclic changes, results in a significant reduction of the heat production and acceleration rates. An appropriate analysis is presented regarding the link of the considered problem with existing observational data and slow solar wind initiation scenarios.

  9. Temperature, Humidity, Wind and Pressure Sensors (THWAPS) Handbook

    SciTech Connect (OSTI)

    Ritsche, MT

    2011-01-17

    The temperature, humidity, wind, and pressure system (THWAPS) provide surface reference values of these measurements for balloon-borne sounding system (SONDE) launches. The THWAPS is located adjacent to the SONDE launch site at the Southern Great Plains (SGP) Central Facility. The THWAPS system is a combination of calibration-quality instruments intended to provide accurate measurements of meteorological conditions near the surface. Although the primary use of the system is to provide accurate surface reference values of temperature, pressure, relative humidity (RH), and wind velocity for comparison with radiosonde readings, the system includes a data logger to record time series of the measured variables.

  10. A Case Study of the Weather Research and Forecasting Model Applied to the Joint Urban 2003 Tracer Field Experiment. Part 1. Wind and Turbulence

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

    Nelson, Matthew A.; Brown, Michael J.; Halverson, Scot A.; Bieringer, Paul E.; Annunzio, Andrew; Bieberbach, George; Meech, Scott

    2015-09-25

    We found that numerical-weather-prediction models are often used to supply the mean wind and turbulence fields for atmospheric transport and dispersion plume models as they provide dense horizontally- and vertically-resolved geographic coverage in comparison to typically sparse monitoring networks. Here, the Weather Research and Forecasting (WRF) model was run over the month-long period of the Joint Urban 2003 field campaign conducted in Oklahoma City and the simulated fields important to transport and dispersion models were compared to measurements from a number of sodars, tower-based sonic anemometers, and balloon soundings located in the greater metropolitan area. Time histories of computed windmore » speed, wind direction, turbulent kinetic energy (e), friction velocity (u* ), and reciprocal Obukhov length (1 / L) were compared to measurements over the 1-month field campaign. Vertical profiles of wind speed, potential temperature (θ ), and e were compared during short intensive operating periods. The WRF model was typically able to replicate the measured diurnal variation of the wind fields, but with an average absolute wind direction and speed difference of 35° and 1.9 m s-1 , respectively. Then, using the Mellor-Yamada-Janjic (MYJ) surface-layer scheme, the WRF model was found to generally underpredict surface-layer TKE but overpredict u* that was observed above a suburban region of Oklahoma City. The TKE-threshold method used by the WRF model’s MYJ surface-layer scheme to compute the boundary-layer height (h) consistently overestimated h derived from a θ gradient method whether using observed or modelled θ profiles.« less

  11. Comparing Wind, Temperature, Pressure, and Humidity

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

    Temperature, Pressure, and Humidity Between the Tropics, Arctic, and Southern Great Plains Using ARM Program Data Grade: 6 th - 9 th Duration: 1 or 2 weeks total, 30 minutes to 1-hour class time a day. Goals: Students will be able to download atmospheric data from the ARM website. They will compare the data from three different locations in the world, discuss why it is different at each location, and be able to answer questions about the data. Objectives: Students will be able to: * Learn how to

  12. Application of a solar wind model driven by turbulence dissipation to a 2D magnetic field configuration

    SciTech Connect (OSTI)

    Lionello, Roberto; Downs, Cooper; Linker, Jon A.; Miki?, Zoran; Velli, Marco E-mail: cdowns@predsci.com E-mail: mikic@predsci.com

    2014-12-01

    Although it is widely accepted that photospheric motions provide the energy source and that the magnetic field must play a key role in the process, the detailed mechanisms responsible for heating the Sun's corona and accelerating the solar wind are still not fully understood. Cranmer et al. developed a sophisticated, one-dimensional (1D), time-steady model of the solar wind with turbulence dissipation. By varying the coronal magnetic field, they obtain, for a single choice of wave properties, a realistic range of slow and fast wind conditions with a sharp latitudinal transition between the two streams. Using a 1D, time-dependent model of the solar wind of Lionello et al., which incorporates turbulent dissipation of Alfvn waves to provide heating and acceleration of the plasma, we have explored a similar configuration, obtaining qualitatively equivalent results. However, our calculations suggest that the rapid transition between slow and fast wind suggested by this 1D model may be disrupted in multidimensional MHD simulations by the requirement of transverse force balance.

  13. Role of ion temperature on scrape-off layer plasma turbulence

    SciTech Connect (OSTI)

    Bisai, N.; Kaw, P. K. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

    2013-04-15

    Turbulence in Scrape-off layer (SOL) of tokamak plasma has been studied numerically using interchange modes with the help of electron continuity, quasineutrality, and ion energy equations. Electron temperature is assumed uniform. We have studied dynamics of seeded plasma blob and plasma turbulence to identify the role of ion temperature and its gradient. The ion temperature elongates the blob poloidally and reduces its radial velocity. Initial dipole nature of the plasma blob potential breaks and generates few more dipoles during its propagation in the SOL. Plasma turbulence simulation shows poloidally elongated density and ion temperature structures that are similar to the seeded blob simulation studies. Fluctuations of the density and ion temperature have been presented as function of scale lengths of the density and ion temperature. Reduction of the SOL width and increase of radial electric field have been measured in the presence of the ion temperature. Particle and energy transports have been also presented as the function of the density and ion temperature scale lengths.

  14. High-Temperature Motor Windings for Downhole Pumps Used in Geothermal

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

    Energy Production | Department of Energy Temperature Motor Windings for Downhole Pumps Used in Geothermal Energy Production High-Temperature Motor Windings for Downhole Pumps Used in Geothermal Energy Production Project objective: Develop and demonstrate high-temperature ESP motor windings for use in Enhanced Geothermal Systems and operation at 300˚C. high_hooker_motor_windings.pdf (377.84 KB) More Documents & Publications High-Temperature Circuit Boards for Use in Geothermal Well

  15. THE VIOLATION OF THE TAYLOR HYPOTHESIS IN MEASUREMENTS OF SOLAR WIND TURBULENCE

    SciTech Connect (OSTI)

    Klein, K. G.; Howes, G. G.; TenBarge, J. M.

    2014-08-01

    Motivated by the upcoming Solar Orbiter and Solar Probe Plus missions, qualitative and quantitative predictions are made for the effects of the violation of the Taylor hypothesis on the magnetic energy frequency spectrum measured in the near-Sun environment. The synthetic spacecraft data method is used to predict observational signatures of the violation for critically balanced Alfvénic turbulence or parallel fast/whistler turbulence. The violation of the Taylor hypothesis can occur in the slow flow regime, leading to a shift of the entire spectrum to higher frequencies, or in the dispersive regime, in which the dissipation range spectrum flattens at high frequencies. It is found that Alfvénic turbulence will not significantly violate the Taylor hypothesis, but whistler turbulence will. The flattening of the frequency spectrum is therefore a key observational signature for fast/whistler turbulence.

  16. Solar-wind turbulence and shear: a superposed-epoch analysis of corotating interaction regions at 1 AU

    SciTech Connect (OSTI)

    Borovsky, Joseph E; Denton, Michael H

    2009-01-01

    A superposed-epoch analysis of ACE and OMNI2 measurements is performed on 27 corotating interaction regions (CIRs) in 2003-2008, with the zero epoch taken to be the stream interface as determined by the maximum of the plasma vorticity. The structure of CIRs is investigated. When the flow measurements are rotated into the local-Parker-spiral coordinate system the shear is seen to be abrupt and intense, with vorticities on the order of 10{sup -5}-10{sup -4} sec{sup -1}. Converging flows perpendicular to the stream interface are seen in the local-Parker-spiral coordinate system and about half of the CIRs show a layer of divergent rebound flow away from the stream interface. Arguments indicate that any spreading of turbulence away from the region where it is produced is limited to about 10{sup 6} km, which is very small compared with the thickness of a CrR. Analysis of the turbulence across the CrRs is performed. When possible, the effects of discontinuities are removed from the data. Fluctuation amplitudes, the Alfvenicity, and the level of Alfvenic correlations all vary smoothly across the CrR. The Alfven ratio exhibits a decrease at the shear zone of the stream interface. Fourier analysis of 4.5-hr subintervals of ACE data is performed and the results are superposed averaged as an ensemble of realizations. The spectral slopes of the velocity, magnetic-field, and total-energy fluctuations vary smoothly across the CIR. The total-energy spectral slope is {approx} 3/2 in the slow and fast wind and in the CrRs. Analysis of the Elsasser inward-outward fluctuations shows a smooth transition across the CrR from an inward-outward balance in the slow wind to an outward dominance in the fast wind. A number of signatures of turbulence driving at the shear zone are sought (entropy change, turbulence amplitude, Alfvenicity, Alfven ratio, spectral slopes, in-out nature): none show evidence of driving of turbulence by shear.

  17. Short-wavelength plasma turbulence and temperature anisotropy instabilities: Recent computational progress

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

    Gary, S. Peter

    2015-04-06

    Plasma turbulence consists of an ensemble of enhanced, broadband electromagnetic fluctuations, typically driven by multi-wave interactions which transfer energy in wavevector space via non- linear cascade processes. In addition, temperature anisotropy instabilities in collisionless plasmas are driven by quasi-linear wave–particle interactions which transfer particle kinetic energy to field fluctuation energy; the resulting enhanced fluctuations are typically narrowband in wavevector magnitude and direction. Whatever their sources, short-wavelength fluctuations are those at which charged particle kinetic, that is, velocity-space, properties are important; these are generally wavelengths of the order of or shorter than the ion inertial length or the thermal ion gyroradius.more » The purpose of this review is to summarize and interpret recent computational results concerning short-wavelength plasma turbulence, short-wavelength temperature anisotropy instabilities and relationships between the two phenomena.« less

  18. Petascale Simulations of Inhomogeneous Alfvén Turbulence in the Solar Wind

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

    | Argonne Leadership Computing Facility 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

  19. MULTI-SPACECRAFT OBSERVATIONS OF LINEAR MODES AND SIDEBAND WAVES IN ION-SCALE SOLAR WIND TURBULENCE

    SciTech Connect (OSTI)

    Perschke, Christopher; Motschmann, Uwe; Narita, Yasuhito; Glassmeier, Karl-Heinz

    2014-10-01

    In the scenario of weak turbulence, energy is believed to be cascaded from smaller to larger wave numbers and frequencies due to weak wave-wave interactions. Based on its perturbative treatment one may regard plasma turbulence as a superposition of linear modes (or normal modes) and sideband waves (or nonlinear modes). In this study, we use magnetic field and plasma measurements of nine solar wind events obtained by the Cluster spacecraft and make extensive use of a high-resolution wave vector analysis method, the Multi-point Signal Resonator technique, to find frequencies and wave vectors of discrete modes on ion kinetic scales in the plasma rest frame. The primarily unstructured wave observations in the frequency-wave number diagram are classified into three distinct linear modes (proton Bernstein modes, helium-alpha Bernstein modes, and kinetic Alfvén waves) and the sideband waves by comparing with the dispersion relations derived theoretically from linear Vlasov theory using observational values of the plasma parameter beta and the propagation angle from the mean magnetic field. About 60% of the observed discrete modes can be explained by the linear modes, primarily as the proton Bernstein and the kinetic Alfvén waves, within the frequency uncertainties, while the rest of the population (about 40%) cannot be classified as linear modes due to the large deviation from dispersion relations. We conclude that both the linear modes and sideband wave components are needed to construct the wave picture of solar wind turbulence on ion-kinetic scales.

  20. Plasma size and power scaling of ion temperature gradient driven turbulence

    SciTech Connect (OSTI)

    Idomura, Yasuhiro; Nakata, Motoki

    2014-02-15

    The transport scaling with respect to plasma size and heating power is studied for ion temperature gradient driven turbulence using a fixed-flux full-f gyrokinetic Eulerian code. It is found that when heating power is scaled with plasma size, the ion heat diffusivity increases with plasma size in a local limit regime, where fixed-gradient ?f simulations predict a gyro-Bohm scaling. In the local limit regime, the transport scaling is strongly affected by the stiffness of ion temperature profiles, which is related to the power degradation of confinement.

  1. Kinetic temperatures of heavy ions in the solar wind

    SciTech Connect (OSTI)

    Bochsler, P.; Geiss, J.; Joos, R.

    1990-11-01

    From a refined analysis of 4 years of data of the ion composition instrument on board ISEE 3 we find that in the overwhelming majority of observations kinetic temperatures of ions are approximately proportional to their masses. The logarithmic average for T(/sup 4/He/sup + +/) is 5.363; for T(O/sup 6 +/) and T(O/sup 7 +/) it is 5.978 and 6.000, respectively, corresponding to T(O)/T(He) = 4.2. For we find 6.52, corresponding to T(Fe)/T(He) = 14. The correlation coefficients between oxygen and helium kinetic temperatures are high (approx.0.78 or above), whereas for the correlation log T(Fe) versus log T(He) we find a value of only 0.44 due to the large measurement uncertainties of T(He). Significant deviations from the mass/temperature proportionality are found at occasions of cool and dense solar wind flow when Coulomb collisions succeed to equilibrate kinetic temperatures of different ions species.

  2. Turbulence-driven coronal heating and improvements to empirical forecasting of the solar wind

    SciTech Connect (OSTI)

    Woolsey, Lauren N.; Cranmer, Steven R.

    2014-06-01

    Forecasting models of the solar wind often rely on simple parameterizations of the magnetic field that ignore the effects of the full magnetic field geometry. In this paper, we present the results of two solar wind prediction models that consider the full magnetic field profile and include the effects of Alfvn waves on coronal heating and wind acceleration. The one-dimensional magnetohydrodynamic code ZEPHYR self-consistently finds solar wind solutions without the need for empirical heating functions. Another one-dimensional code, introduced in this paper (The Efficient Modified-Parker-Equation-Solving Tool, TEMPEST), can act as a smaller, stand-alone code for use in forecasting pipelines. TEMPEST is written in Python and will become a publicly available library of functions that is easy to adapt and expand. We discuss important relations between the magnetic field profile and properties of the solar wind that can be used to independently validate prediction models. ZEPHYR provides the foundation and calibration for TEMPEST, and ultimately we will use these models to predict observations and explain space weather created by the bulk solar wind. We are able to reproduce with both models the general anticorrelation seen in comparisons of observed wind speed at 1 AU and the flux tube expansion factor. There is significantly less spread than comparing the results of the two models than between ZEPHYR and a traditional flux tube expansion relation. We suggest that the new code, TEMPEST, will become a valuable tool in the forecasting of space weather.

  3. The effect of turbulent kinetic energy on inferred ion temperature from neutron spectra

    SciTech Connect (OSTI)

    Murphy, T. J.

    2014-07-15

    Measuring the width of the energy spectrum of fusion-produced neutrons from deuterium (DD) or deuterium-tritium (DT) plasmas is a commonly used method for determining the ion temperature in inertial confinement fusion (ICF) implosions. In a plasma with a Maxwellian distribution of ion energies, the spread in neutron energy arises from the thermal spread in the center-of-mass velocities of reacting pairs of ions. Fluid velocities in ICF are of a similar magnitude as the center-of-mass velocities and can lead to further broadening of the neutron spectrum, leading to erroneous inference of ion temperature. Motion of the reacting plasma will affect DD and DT neutrons differently, leading to disagreement between ion temperatures inferred from the two reactions. This effect may be a contributor to observations over the past decades of ion temperatures higher than expected from simulations, ion temperatures in disagreement with observed yields, and different temperatures measured in the same implosion from DD and DT neutrons. This difference in broadening of DD and DT neutrons also provides a measure of turbulent motion in a fusion plasma.

  4. Turbulence transport modeling of the temporal outer heliosphere

    SciTech Connect (OSTI)

    Adhikari, L.; Zank, G. P.; Hu, Q.; Dosch, A.

    2014-09-20

    The solar wind can be regarded as a turbulent magnetofluid, evolving in an expanding solar wind and subject to turbulent driving by a variety of in situ sources. Furthermore, the solar wind and the drivers of turbulence are highly time-dependent and change with solar cycle. Turbulence transport models describing low-frequency magnetic and velocity fluctuations in the solar wind have so far neglected solar cycle effects. Here we consider the effects of solar cycle variability on a turbulence transport model developed by Zank et al. This model is appropriate for the solar wind beyond about 1 AU, and extensions have described the steady-state dependence of the magnetic energy density fluctuations, correlation length, and solar wind temperature throughout the outer heliosphere. We find that the temporal solar wind introduces a periodic variability, particularly beyond ?10 AU, in the magnetic energy density fluctuations, correlation length, and solar wind temperature. The variability is insufficient to account for the full observed variability in these quantities, but we find that the time-dependent solutions trace the steady-state solutions quite well, suggesting that the steady-state models are reasonable first approximations.

  5. Analysis of CASES-99 Lidar and Turbulence Data in Support of Wind Turbine Effects: April 1, 2001 to Januay 31, 2003

    SciTech Connect (OSTI)

    Banta, R. M.

    2003-06-01

    The nocturnal low-level jet (LLJ) of the Great Plains of the central United States has been identified as a promising source of high-momentum wind flow for wind energy. The acceleration of the winds after sunset above the surface produces a jet profile in the wind velocity, with maximum speeds that often exceed 10 m s-1 or more at heights near 100 m or more. These high wind speeds are advantageous for wind energy generation. The high speeds aloft, however, also produce a region of high shear between the LLJ and the earth's surface, where the nocturnal flow is often calm or nearly so. This shear zone below the LLJ generates atmospheric waves and turbulence that can cause strong vibration in the turbine rotors. It has been suggested that these vibrations contribute to premature failures in large wind turbines, which, of course, would be a considerable disadvantage for wind energy applications. In October 1999, a field project called the Cooperative Atmosphere-Surface Exchange Study 1999 campaign, or CASES-99, was conducted in southeastern Kansas to study the nocturnal stable boundary layer. One of the instruments deployed during CASES-99 was the High-Resolution Doppler Lidar, a new scanning, remote-sensing, wind-mapping instrument.

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

    SciTech Connect (OSTI)

    Hollweg, Joseph V.; Chandran, Benjamin D. G.; Kaghashvili, Edisher Kh. E-mail: ekaghash@aer.com

    2013-06-01

    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.

  7. Brushless exciters using a high temperature superconducting field winding

    DOE Patents [OSTI]

    Garces, Luis Jose; Delmerico, Robert William; Jansen, Patrick Lee; Parslow, John Harold; Sanderson, Harold Copeland; Sinha, Gautam

    2008-03-18

    A brushless exciter for a synchronous generator or motor generally includes a stator and a rotor rotatably disposed within the stator. The rotor has a field winding and a voltage rectifying bridge circuit connected in parallel to the field winding. A plurality of firing circuits are connected the voltage rectifying bridge circuit. The firing circuit is configured to fire a signal at an angle of less than 90.degree. or at an angle greater than 90.degree.. The voltage rectifying bridge circuit rectifies the AC voltage to excite or de-excite the field winding.

  8. Observations of the scale-dependent turbulence and evaluation of the flux-gradient relationship for sensible heat for a closed Douglas-Fir canopy in very weak wind conditions

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

    Vickers, D.; Thomas, C.

    2014-05-13

    Observations of the scale-dependent turbulent fluxes and variances above, within and beneath a tall closed Douglas-Fir canopy in very weak winds are examined. The daytime subcanopy vertical velocity spectra exhibit a double-peak structure with peaks at time scales of 0.8 s and 51.2 s. A double-peak structure is also observed in the daytime subcanopy heat flux cospectra. The daytime momentum flux cospectra inside the canopy and in the subcanopy are characterized by a relatively large cross-wind component, likely due to the extremely light and variable winds, such that the definition of a mean wind direction, and subsequent partitioning of themore » momentum flux into along- and cross-wind components, has little physical meaning. Positive values of both momentum flux components in the subcanopy contribute to upward transfer of momentum, consistent with the observed mean wind speed profile. In the canopy at night at the smallest resolved scales, we find relatively large momentum fluxes (compared to at larger scales), and increasing vertical velocity variance with decreasing time scale, consistent with very small eddies likely generated by wake shedding from the canopy elements that transport momentum but not heat. We find unusually large values of the velocity aspect ratio within the canopy, consistent with enhanced suppression of the horizontal wind components compared to the vertical by the canopy. The flux-gradient approach for sensible heat flux is found to be valid for the subcanopy and above-canopy layers when considered separately; however, single source approaches that ignore the canopy fail because they make the heat flux appear to be counter-gradient when in fact it is aligned with the local temperature gradient in both the subcanopy and above-canopy layers. Modeled sensible heat fluxes above dark warm closed canopies are likely underestimated using typical values of the Stanton number.« less

  9. A study of self organized criticality in ion temperature gradient mode driven gyrokinetic turbulence

    SciTech Connect (OSTI)

    Mavridis, M.; Isliker, H.; Vlahos, L.; Grler, T.; Jenko, F.; Told, D.

    2014-10-15

    An investigation on the characteristics of self organized criticality (Soc) in ITG mode driven turbulence is made, with the use of various statistical tools (histograms, power spectra, Hurst exponents estimated with the rescaled range analysis, and the structure function method). For this purpose, local non-linear gyrokinetic simulations of the cyclone base case scenario are performed with the GENE software package. Although most authors concentrate on global simulations, which seem to be a better choice for such an investigation, we use local simulations in an attempt to study the locally underlying mechanisms of Soc. We also study the structural properties of radially extended structures, with several tools (fractal dimension estimate, cluster analysis, and two dimensional autocorrelation function), in order to explore whether they can be characterized as avalanches. We find that, for large enough driving temperature gradients, the local simulations exhibit most of the features of Soc, with the exception of the probability distribution of observables, which show a tail, yet they are not of power-law form. The radial structures have the same radial extent at all temperature gradients examined; radial motion (transport) though appears only at large temperature gradients, in which case the radial structures can be interpreted as avalanches.

  10. Observations of the scale-dependent turbulence and evaluation of the flux–gradient relationship for sensible heat for a closed Douglas-fir canopy in very weak wind conditions

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

    Vickers, D.; Thomas, C. K.

    2014-09-16

    Observations of the scale-dependent turbulent fluxes, variances, and the bulk transfer parameterization for sensible heat above, within, and beneath a tall closed Douglas-fir canopy in very weak winds are examined. The daytime sub-canopy vertical velocity spectra exhibit a double-peak structure with peaks at timescales of 0.8 s and 51.2 s. A double-peak structure is also observed in the daytime sub-canopy heat flux co-spectra. The daytime momentum flux co-spectra in the upper bole space and in the sub-canopy are characterized by a relatively large cross-wind component, likely due to the extremely light and variable winds, such that the definition of amore » mean wind direction, and subsequent partitioning of the momentum flux into along- and cross-wind components, has little physical meaning. Positive values of both momentum flux components in the sub-canopy contribute to upward transfer of momentum, consistent with the observed sub-canopy secondary wind speed maximum. For the smallest resolved scales in the canopy at nighttime, we find increasing vertical velocity variance with decreasing timescale, consistent with very small eddies possibly generated by wake shedding from the canopy elements that transport momentum, but not heat. Unusually large values of the velocity aspect ratio within the canopy were observed, consistent with enhanced suppression of the horizontal wind components compared to the vertical by the very dense canopy. The flux–gradient approach for sensible heat flux is found to be valid for the sub-canopy and above-canopy layers when considered separately in spite of the very small fluxes on the order of a few W m−2 in the sub-canopy. However, single-source approaches that ignore the canopy fail because they make the heat flux appear to be counter-gradient when in fact it is aligned with the local temperature gradient in both the sub-canopy and above-canopy layers. While sub-canopy Stanton numbers agreed well with values typically reported

  11. Climatological summary of wind and temperature data for the Hanford Meteorology Monitoring Network

    SciTech Connect (OSTI)

    Glantz, C.S.; Schwartz, M.N.; Burk, K.W.; Kasper, R.B.; Ligotke, M.W.; Perrault, P.J.

    1990-09-01

    This document presents climatological summaries of wind and temperature data collected at the twenty-five monitoring stations operated by the Hanford Meteorology Monitoring Network. The climatological analyses presented here involve hourly averaged wind data collected over an 8-year period beginning in 1982 (fewer wind data are available for the several monitoring stations that began full-time operation after 1982) and hourly averaged air temperature data collected over 2-year period beginning in mid-1988. The tables and figures presented in this document illustrate the spatial and temporal variation of meteorological parameters across the Hanford Site and the surrounding areas. This information is useful for emergency response applications, routine meteorological forecasting, planning and scheduling operations, facility design, and environmental impact studies.

  12. STOCHASTIC HEATING, DIFFERENTIAL FLOW, AND THE ALPHA-TO-PROTON TEMPERATURE RATIO IN THE SOLAR WIND

    SciTech Connect (OSTI)

    Chandran, B. D. G.; Verscharen, D.; Isenberg, P. A.; Bourouaine, S.; Quataert, E.; Kasper, J. C. E-mail: s.bourouaine@unh.edu E-mail: daniel.verscharen@unh.edu E-mail: jkasper@cfa.harvard.edu

    2013-10-10

    We extend previous theories of stochastic ion heating to account for the motion of ions along the magnetic field B . We derive an analytic expression for the temperature ratio T{sub i}/T{sub p} in the solar wind assuming that stochastic heating is the dominant ion heating mechanism, where T{sub i} is the perpendicular temperature of species i and T{sub p} is the perpendicular proton temperature. This expression describes how T{sub i}/T{sub p} depends upon U{sub i} and ?{sub ?p}, where U{sub i} is the average velocity along B of species i in the proton frame and ?{sub ?p} is the ratio of the parallel proton pressure to the magnetic pressure, which we take to be ?< 1. We compare our model with previously published measurements of alpha particles and protons from the Wind spacecraft. We find that stochastic heating offers a promising explanation for the dependence of T{sub ?}/T{sub p} on U{sub ?} and ?{sub ?p} when the fractional cross helicity and Alfvn ratio at the proton-gyroradius scale have values that are broadly consistent with solar-wind measurements. We also predict how the temperatures of other ion species depend on their drift speeds.

  13. INSTABILITIES DRIVEN BY THE DRIFT AND TEMPERATURE ANISOTROPY OF ALPHA PARTICLES IN THE SOLAR WIND

    SciTech Connect (OSTI)

    Verscharen, Daniel; Bourouaine, Sofiane; Chandran, Benjamin D. G. E-mail: s.bourouaine@unh.edu

    2013-08-20

    We investigate the conditions under which parallel-propagating Alfven/ion-cyclotron (A/IC) waves and fast-magnetosonic/whistler (FM/W) waves are driven unstable by the differential flow and temperature anisotropy of alpha particles in the solar wind. We focus on the limit in which w{sub Parallel-To {alpha}} {approx}> 0.25v{sub A}, where w{sub Parallel-To {alpha}} is the parallel alpha-particle thermal speed and v{sub A} is the Alfven speed. We derive analytic expressions for the instability thresholds of these waves, which show, e.g., how the minimum unstable alpha-particle beam speed depends upon w{sub Parallel-To {alpha}}/v{sub A}, the degree of alpha-particle temperature anisotropy, and the alpha-to-proton temperature ratio. We validate our analytical results using numerical solutions to the full hot-plasma dispersion relation. Consistent with previous work, we find that temperature anisotropy allows A/IC waves and FM/W waves to become unstable at significantly lower values of the alpha-particle beam speed U{sub {alpha}} than in the isotropic-temperature case. Likewise, differential flow lowers the minimum temperature anisotropy needed to excite A/IC or FM/W waves relative to the case in which U{sub {alpha}} = 0. We discuss the relevance of our results to alpha particles in the solar wind near 1 AU.

  14. Magnetic island evolution in the presence of ion-temperature gradient-driven turbulence

    SciTech Connect (OSTI)

    Ishizawa, A.; Waelbroeck, F. L.

    2013-12-15

    Turbulence is known to drive and sustain magnetic islands of width equal to multiples of the Larmor radius. The nature of the drive is studied here by means of numerical simulations of a fluid electrostatic model in 2D (single helicity) sheared-slab geometry. The electrostatic model eliminates the coalescence of short wavelength islands as a mechanism for sustaining longer wavelength islands. In quiescent islands, the polarization current, which depends on the propagation velocity of the island through the plasma, plays a critical role in determining the growth or decay of island chains. For turbulent islands, the unforced propagation velocity is significantly changed by strong zonal flow. The simulations show, however, that the turbulent fluctuations in the current density are much larger and faster than those in the zonal flow, and that they dominate the steady-state perturbed current density. In order to distinguish the roles of the zonal flow from the direct action of the fluctuations on the islands, a new diagnostic is implemented. This new diagnostic separates the effects of all the sources of parallel current. These are the curvature (which drives Pfirsch-Schlter currents) and the divergences of the viscous and Reynolds stresses (the latter driving polarization currents). The new diagnostic also enables the contributions from short and long wavelengths to be separated for each term. It shows that in the absence of curvature, the drive is dominated by the contributions to the polarization current from the short wavelength fluctuations, while the long-wavelength fluctuations play a stabilizing role. In the presence of unfavorable curvature, by contrast, the effects of the short- and long-wavelength contributions of the polarization current reverse roles but nearly cancel, leaving the Pfirsch-Schlter current as the dominant drive.

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

    SciTech Connect (OSTI)

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

    2010-10-01

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

  16. See the Wind

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

    ... Engineers are also concerned about wind shear and turbulence as this can cause a great deal of stress on their gearbox and bearings in their turbines. Characterizing Shear and Wind ...

  17. Temperature, Oxygen, and Soot-Volume-Fraction Measurements in a Turbulent C2H4-Fueled Jet Flame

    SciTech Connect (OSTI)

    Kearney, Sean P.; Guildenbecher, Daniel Robert; Winters, Caroline; Farias, Paul Abraham; Grasser, Thomas W.; Hewson, John C.

    2015-09-01

    We present a detailed set of measurements from a piloted, sooting, turbulent C 2 H 4 - fueled diffusion flame. Hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering (CARS) is used to monitor temperature and oxygen, while laser-induced incandescence (LII) is applied for imaging of the soot volume fraction in the challenging jet-flame environment at Reynolds number, Re = 20,000. Single-laser shot results are used to map the mean and rms statistics, as well as probability densities. LII data from the soot-growth region of the flame are used to benchmark the soot source term for one-dimensional turbulence (ODT) modeling of this turbulent flame. The ODT code is then used to predict temperature and oxygen fluctuations higher in the soot oxidation region higher in the flame.

  18. High-Temperature Motor Windings for Downhole Pumps Used in Geothermal Energy Production

    SciTech Connect (OSTI)

    Hooker, Matthew; Hazelton, Craig; Kano, Kimi

    2010-12-31

    The development of highly reliable downhole equipment is an essential element in enabling the widespread utilization of Enhanced Geothermal Systems (EGS). The downhole equipment used in these systems will be required to operate at high voltages and temperatures on the order of 200 to 250C (and eventually to 300?C). These conditions exceed the practical operating ranges of currently available thermoplastic wire insulations, and thus limit the operating lifetime of tools such as Electric Submersible Pumps (ESPs). In this work, high-temperature insulations based on composite materials were developed and demonstrated. The products of this work were found to exhibit electrical resistivities and dielectric breakdown strengths that PEEK at temperatures above 250C. In addition, sub-scale motor windings were fabricated and tested to validate the performance of this technology

  19. Solar wind stream interaction: Electron temperature and heat flux rise in the low-speed stream

    SciTech Connect (OSTI)

    Alexander, P.; Duhau, S. )

    1990-11-01

    The strong compression produced in two-stream interaction regions in the solar wind is a local source of heating. The study of the distribution of that energy between heat and internal energy provides valuable information about transport processes. In the present work, the electron heat flux and temperature rise in the compression produced within the low-speed portion of the interaction region is predicted using a new heat conduction law valid for collisionless plasmas with isotropic electron temperature, introduced recently by one of the authors. Equations are found for the electron heat flux and temperature rise as functions of two parameters, one related to the strength of the compression and the other one to the heat flux at the boundaries of the region under study. These equations lead to agreement between theory and experiment.

  20. LIMITS ON ALPHA PARTICLE TEMPERATURE ANISOTROPY AND DIFFERENTIAL FLOW FROM KINETIC INSTABILITIES: SOLAR WIND OBSERVATIONS

    SciTech Connect (OSTI)

    Bourouaine, Sofiane; Verscharen, Daniel; Chandran, Benjamin D. G.; Maruca, Bennett A.; Kasper, Justin C.

    2013-11-01

    Previous studies have shown that the observed temperature anisotropies of protons and alpha particles in the solar wind are constrained by theoretical thresholds for pressure and anisotropy driven instabilities such as the Alfvn/ion-cyclotron (A/IC) and fast-magnetosonic/whistler (FM/W) instabilities. In this Letter, we use a long period of in situ measurements provided by the Wind spacecraft's Faraday cups to investigate the combined constraint on the alpha proton differential flow velocity and the alpha particle temperature anisotropy due to A/IC and FM/W instabilities. We show that the majority of the data are constrained to lie within the region of parameter space in which A/IC and FM/W waves are either stable or have extremely low growth rates. In the minority of observed cases in which the growth rate of the A/IC (FM/W) instability is comparatively large, we find relatively higher values of T {sub ?}/T {sub p} (T {sub ??}/T {sub ?p}) when the alpha proton differential flow velocity is small, where T {sub ?} and T {sub p} (T {sub ??} and T {sub ?p}) are the perpendicular (parallel) temperatures of alpha particles and protons. We conjecture that this observed feature might arise from preferential alpha particle heating which can drive the alpha particles beyond the instability thresholds.

  1. System and method for monitoring and controlling stator winding temperature in a de-energized AC motor

    DOE Patents [OSTI]

    Lu, Bin; Luebke, Charles John; Habetler, Thomas G.; Zhang, Pinjia; Becker, Scott K.

    2011-12-27

    A system and method for measuring and controlling stator winding temperature in an AC motor while idling is disclosed. The system includes a circuit having an input connectable to an AC source and an output connectable to an input terminal of a multi-phase AC motor. The circuit further includes a plurality of switching devices to control current flow and terminal voltages in the multi-phase AC motor and a controller connected to the circuit. The controller is configured to activate the plurality of switching devices to create a DC signal in an output of the motor control device corresponding to an input to the multi-phase AC motor, determine or estimate a stator winding resistance of the multi-phase AC motor based on the DC signal, and estimate a stator temperature from the stator winding resistance. Temperature can then be controlled and regulated by DC injection into the stator windings.

  2. Characterization of Superhydrophobic Surfaces for Anti-icing in a Low-Temperature Wind Tunnel

    SciTech Connect (OSTI)

    Swarctz, Christopher; Alijallis, Elias; Hunter, Scott Robert; Simpson, John T; Choi, Chang-Hwan

    2010-01-01

    In this study, a closed loop low-temperature wind tunnel was custom-built and uniquely used to investigate the anti-icing mechanism of superhydrophobic surfaces in regulated flow velocities, temperatures, humidity, and water moisture particle sizes. Silica nanoparticle-based hydrophobic coatings were tested as superhydrophobic surface models. During tests, images of ice formation were captured by a camera and used for analysis of ice morphology. Prior to and after wind tunnel testing, apparent contact angles of water sessile droplets on samples were measured by a contact angle meter to check degradation of surface superhydrophobicity. A simple peel test was also performed to estimate adhesion of ice on the surfaces. When compared to an untreated sample, superhydrophobic surfaces inhibited initial ice formation. After a period of time, random droplet strikes attached to the superhydrophobic surfaces and started to coalesce with previously deposited ice droplets. These sites appear as mounds of accreted ice across the surface. The appearance of the ice formations on the superhydrophobic samples is white rather than transparent, and is due to trapped air. These ice formations resemble soft rime ice rather than the transparent glaze ice seen on the untreated sample. Compared to untreated surfaces, the icing film formed on superhydrophobic surfaces was easy to peel off by shear flows.

  3. ASYMMETRIC SOLAR WIND ELECTRON DISTRIBUTIONS

    SciTech Connect (OSTI)

    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)

    2012-08-20

    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.

  4. Vertical Axis Wind Turbine

    Energy Science and Technology Software Center (OSTI)

    2002-04-01

    Blade fatigue life is an important element in determining the economic viability of the Vertical-Axis Wind Turbine (VAWT). VAWT-SAL Vertical Axis Wind Turbine- Stochastic Aerodynamic Loads Ver 3.2 numerically simulates the stochastic (random0 aerodynamic loads of the Vertical-Axis Wind Turbine (VAWT) created by the atomspheric turbulence. The program takes into account the rotor geometry, operating conditions, and assumed turbulence properties.

  5. Turbine Inflow Characterization at the National Wind Technology Center

    SciTech Connect (OSTI)

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

    2012-01-01

    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.

  6. Turbine Inflow Characterization at the National Wind Technology Center: Preprint

    SciTech Connect (OSTI)

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

    2012-01-01

    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 shown 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.

  7. Probability density function treatment of turbulence/chemistry interactions during the ignition of a temperature-stratified mixture for application to HCCI engine modeling

    SciTech Connect (OSTI)

    Bisetti, Fabrizio; Chen, J.-Y.; Hawkes, Evatt R.; Chen, Jacqueline H.

    2008-12-15

    Homogeneous charge compression ignition (HCCI) engine technology promises to reduce NO{sub x} and soot emissions while achieving high thermal efficiency. Temperature and mixture stratification are regarded as effective means of controlling the start of combustion and reducing the abrupt pressure rise at high loads. Probability density function methods are currently being pursued as a viable approach to modeling the effects of turbulent mixing and mixture stratification on HCCI ignition. In this paper we present an assessment of the merits of three widely used mixing models in reproducing the moments of reactive scalars during the ignition of a lean hydrogen/air mixture ({phi}=0.1, p=41atm, and T=1070 K) under increasing temperature stratification and subject to decaying turbulence. The results from the solution of the evolution equation for a spatially homogeneous joint PDF of the reactive scalars are compared with available direct numerical simulation (DNS) data [E.R. Hawkes, R. Sankaran, P.P. Pebay, J.H. Chen, Combust. Flame 145 (1-2) (2006) 145-159]. The mixing models are found able to quantitatively reproduce the time history of the heat release rate, first and second moments of temperature, and hydroxyl radical mass fraction from the DNS results. Most importantly, the dependence of the heat release rate on the extent of the initial temperature stratification in the charge is also well captured. (author)

  8. BOUndary Plasma Turbulence

    Energy Science and Technology Software Center (OSTI)

    2008-01-25

    BOUT is a parallelized 3D nonlocal electromagnetic turbulence code. The principal calculations are the boundary plasma turbulence in a realistic magnetic geometry. BOUT uses fluid Braginskii equations for plasma vorticity, density, electron and ion temperature and Parallel mementum. With sources added in the core-edge region and sinks in the scrape-off-layer (SOL), BOUT follows the self-consistent profile evolution together with turbulence. BOUT also includes coupling to a magnetohyfrodynamic equlibrium (EFIT package) and a two-dimensional hydrodynamic edgemore » transport model (UEDGE package).« less

  9. Effects of turbulence model on convective heat transfer of coolant flow in a prismatic very high temperature reactor core

    SciTech Connect (OSTI)

    Lee, S. N.; Tak, N. I.; Kim, M. H.; Noh, J. M.

    2012-07-01

    The existing study of Spall et al. shows that only {nu}{sup 2}-f turbulence model well matches with the experimental data of Shehata and McEligot which were obtained under strongly heated gas flows. Significant over-predictions in those literatures were observed in the convective heat transfer with the other famous turbulence models such as the k-{epsilon} and k-{omega} models. In spite of such good evidence about the performance of the{nu}{sup 2}-f model, the application of the {nu}{sup 2}-f model to the thermo-fluid analysis of a prismatic core is very rare. In this paper, therefore, the convective heat transfer of the coolant flow in a prismatic core has been investigated using the {nu}{sup 2}-f model. Computational fluid dynamics (CFD) calculations have been carried out for the typical unit cell geometry of a prismatic fuel column with typical operating conditions of prismatic designs. The tested Reynolds numbers of the coolant flow are 10,000, 20,000, 30,000 and 50,000. The predicted Nusselt numbers with the {nu}{sup 2}-f model are compared with the results by the other turbulence models (k-{epsilon} and SST) as well as the empirical correlations. (authors)

  10. Applied Turbulent Combustion

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

    Turbulent Combustion - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Energy Defense Waste Management Programs Advanced Nuclear

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

    SciTech Connect (OSTI)

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

    2012-01-01

    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.

  12. Wind farm array wake losses

    SciTech Connect (OSTI)

    Baker, R.W.; McCarthy, E.F.

    1997-12-31

    A wind turbine wake study was conducted in the summer of 1987 at an Altamont Pass wind electric generating facility. The wind speed deficits, turbulence, and power deficits from an array consisting of several rows of wind turbines is discussed. A total of nine different test configurations were evaluated for a downwind spacing ranging from 7 rotor diameters (RD) to 34 RD and a cross wind spacing of 1.3 RD and 2.7 RD. Wake power deficits of 15% were measured at 16 RD and power losses of a few percent were even measurable at 27 RD for the closer cross wind spacing. For several rows of turbines separated by 7-9 RD the wake zones overlapped and formed compound wakes with higher velocity deficits. The wind speed and direction turbulence in the wake was much higher than the ambient turbulence. The results from this study are compared to the findings from other similar field measurements.

  13. Wind Energy Basics | NREL

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

    Wind Energy Basics 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. Text Version 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

  14. Magnetohydrodynamic turbulence: Observation and experiment

    SciTech Connect (OSTI)

    Brown, M. R.; Schaffner, D. A.; Weck, P. J.

    2015-05-15

    We provide a tutorial on the paradigms and tools of magnetohydrodynamic (MHD) turbulence. The principal paradigm is that of a turbulent cascade from large scales to small, resulting in power law behavior for the frequency power spectrum for magnetic fluctuations E{sub B}(f). We will describe five useful statistical tools for MHD turbulence in the time domain: the temporal autocorrelation function, the frequency power spectrum, the probability distribution function of temporal increments, the temporal structure function, and the permutation entropy. Each of these tools will be illustrated with an example taken from MHD fluctuations in the solar wind. A single dataset from the Wind satellite will be used to illustrate all five temporal statistical tools.

  15. LIDAR Wind Speed Measurements of Evolving Wind Fields

    SciTech Connect (OSTI)

    Simley, E.; Pao, L. Y.

    2012-07-01

    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.

  16. ARM - Wind Chill Calculations

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

    CalculatorsWind Chill Calculations Outreach Home Room News Publications Traditional Knowledge Kiosks Barrow, Alaska Tropical Western Pacific Site Tours Contacts Students Study Hall About ARM Global Warming 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 body owing to the combination of temperature and wind speed. From 1945 to 2001, Wind Chill was calculated by the Siple

  17. Kinetic temperatures of iron ions in the solar wind observed with STEREO/PLASTIC

    SciTech Connect (OSTI)

    Bochsler, Peter; Lee, Martin A.; Popecki, Mark A.; Galvin, Antoinette B.; Kistler, Lynn M.; Moebius, Eberhard; Farrugia, Charles J.; Kucharek, Harald; Simunac, Kristin D. C.; Karrer, Reto; Blush, Lisa M.; Daoudi, Hagar; Wurz, Peter; Klecker, Berndt; Wimmer-Schweingruber, Robert F.; Thompson, Barbara; Luhmann, Janet G.; Jian, Lan K.; Russell, Christopher T.; Opitz, Andrea

    2010-03-25

    STEREO/PLASTIC provides detailed information on the three-dimensional velocity distributions of solar wind iron ions with a time resolution of 5 minutes. In general the distributions at 1 AU contain complicated structures showing persistence over several records, i.e., over intervals of up to 30 minutes, but no clear correlation of the properties of these distributions with the direction of the ambient magnetic field is evident. We have performed a statistical analysis using nearly 9000 observations. Iron ions follow the same trends as protons, alpha particles, and electrons: The ratio T{sub perpendicular}/T{sub ||} seems to be limited by the ion cyclotron instability, whereas T{sub ||} /T{sub perpendicular} is bounded by the firehose instability.

  18. A frequency-agile lidar for simultaneous measurement of temperature and radial wind in the mesopause region without sodium density contamination

    SciTech Connect (OSTI)

    White, M.; Golias, D.; Krueger, D.A.; She, C.Y.

    1996-12-31

    With early and ongoing climatological surveys established, continuing observations of the mesopause region over Fort Collins, Colorado are discussed, emphasizing the modification of Colorado State University`s two frequency lidar for simultaneous measurement of temperature vis Doppler Broadening and radial wind via Doppler shift. The application of a frequency-agile, tandem acousto-optical modulator system for three-frequency temperature/wind measurements free of contamination from atmospheric Na density fluctuations, as well as frequency characterization of this new apparatus, and future applications are considered.

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

    SciTech Connect (OSTI)

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

    2009-12-01

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

  20. Magnetized Turbulent Dynamo in Protogalaxies

    SciTech Connect (OSTI)

    Leonid Malyshkin; Russell M. Kulsrud

    2002-01-28

    The prevailing theory for the origin of cosmic magnetic fields is that they have been amplified to their present values by the turbulent dynamo inductive action in the protogalactic and galactic medium. Up to now, in calculation of the turbulent dynamo, it has been customary to assume that there is no back reaction of the magnetic field on the turbulence, as long as the magnetic energy is less than the turbulent kinetic energy. This assumption leads to the kinematic dynamo theory. However, the applicability of this theory to protogalaxies is rather limited. The reason is that in protogalaxies the temperature is very high, and the viscosity is dominated by magnetized ions. As the magnetic field strength grows in time, the ion cyclotron time becomes shorter than the ion collision time, and the plasma becomes strongly magnetized. As a result, the ion viscosity becomes the Braginskii viscosity. Thus, in protogalaxies the back reaction sets in much earlier, at field strengths much lower than those which correspond to field-turbulence energy equipartition, and the turbulent dynamo becomes what we call the magnetized turbulent dynamo. In this paper we lay the theoretical groundwork for the magnetized turbulent dynamo. In particular, we predict that the magnetic energy growth rate in the magnetized dynamo theory is up to ten times larger than that in the kinematic dynamo theory. We also briefly discuss how the Braginskii viscosity can aid the development of the inverse cascade of magnetic energy after the energy equipartition is reached.

  1. Calming the Waters: The Impact of Turbulence on Tidal Energy Systems

    Office of Energy Efficiency and Renewable Energy (EERE)

    New research is helping the emerging tidal energy industry learn from their counterparts in the wind industry. By considering the effects of atmospheric turbulence when developing turbine designs,...

  2. Momentum transport in the vicinity of q{sub min} in reverse shear tokamaks due to ion temperature gradient turbulence

    SciTech Connect (OSTI)

    Singh, Rameswar; Laboratoire de Physique des Plasmas, Ecole Polytechnique route de Saclay, 91128 Palaiseau Cedex ; Singh, R; WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 ; Jhang, Hogun; Diamond, P. H.; Center for Momentum Transport and Flow Organization, University of California, San Diego, California 92093; Center for Astrophysics and Space Sciences, University of California San Diego, 9500 Gilman Dr., La Jolla, California 92093-0424

    2014-01-15

    We present an analytic study of momentum transport of tokamak plasmas in the vicinity of minimum safety factor (q) position in reversed magnetic shear configuration. Slab ion temperature gradient modes with an equilibrium flow profile are considered in this study. Quasi-linear calculations of momentum flux clearly show the novel effects of q-curvature on the generation of intrinsic rotation and mean poloidal flow without invoking reflectional symmetry breaking of parallel wavenumber (k{sub ?}). This q-curvature effect originates from the inherent asymmetry in k{sub ?} populations with respect to a rational surface due to the quadratic proportionality of k{sub ?} when q-curvature is taken into account. Discussions are made of possible implications of q-curvature induced plasma flows on internal transport barrier formation in reversed shear tokamaks.

  3. Turbulent combustion

    SciTech Connect (OSTI)

    Talbot, L.; Cheng, R.K.

    1993-12-01

    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.

  4. A comparison of weak-turbulence and particle-in-cell simulations of weak electron-beam plasma interaction

    SciTech Connect (OSTI)

    Ratcliffe, H. Brady, C. S.; Che Rozenan, M. B.; Nakariakov, V. M.

    2014-12-15

    Quasilinear theory has long been used to treat the problem of a weak electron beam interacting with plasma and generating Langmuir waves. Its extension to weak-turbulence theory treats resonant interactions of these Langmuir waves with other plasma wave modes, in particular, ion-sound waves. These are strongly damped in plasma of equal ion and electron temperatures, as sometimes seen in, for example, the solar corona and wind. Weak turbulence theory is derived in the weak damping limit, with a term describing ion-sound wave damping then added. In this paper, we use the EPOCH particle-in-cell code to numerically test weak turbulence theory for a range of electron-ion temperature ratios. We find that in the cold ion limit, the results agree well, but for increasing ion temperature the three-wave resonance becomes broadened in proportion to the ion-sound wave damping rate. Additionally, we establish lower limits on the number of simulation particles needed to accurately reproduce the electron and wave distributions in their saturated states and to reproduce their intermediate states and time evolution. These results should be taken into consideration in, for example, simulations of plasma wave generation in the solar corona of Type III solar radio bursts from the corona to the solar wind and in weak turbulence investigations of ion-acoustic lines in the ionosphere.

  5. Wind Measurements from Arc Scans with Doppler Wind Lidar

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

    Wang, H.; Barthelmie, R. J.; Clifton, Andy; Pryor, S. C.

    2015-11-25

    When defining optimal scanning geometries for scanning lidars for wind energy applications, we found that it is still an active field of research. Our paper evaluates uncertainties associated with arc scan geometries and presents recommendations regarding optimal configurations in the atmospheric boundary layer. The analysis is based on arc scan data from a Doppler wind lidar with one elevation angle and seven azimuth angles spanning 30° and focuses on an estimation of 10-min mean wind speed and direction. When flow is horizontally uniform, this approach can provide accurate wind measurements required for wind resource assessments in part because of itsmore » high resampling rate. Retrieved wind velocities at a single range gate exhibit good correlation to data from a sonic anemometer on a nearby meteorological tower, and vertical profiles of horizontal wind speed, though derived from range gates located on a conical surface, match those measured by mast-mounted cup anemometers. Uncertainties in the retrieved wind velocity are related to high turbulent wind fluctuation and an inhomogeneous horizontal wind field. Moreover, the radial velocity variance is found to be a robust measure of the uncertainty of the retrieved wind speed because of its relationship to turbulence properties. It is further shown that the standard error of wind speed estimates can be minimized by increasing the azimuthal range beyond 30° and using five to seven azimuth angles.« less

  6. Wind Measurements from Arc Scans with Doppler Wind Lidar

    SciTech Connect (OSTI)

    Wang, H.; Barthelmie, R. J.; Clifton, Andy; Pryor, S. C.

    2015-11-25

    When defining optimal scanning geometries for scanning lidars for wind energy applications, we found that it is still an active field of research. Our paper evaluates uncertainties associated with arc scan geometries and presents recommendations regarding optimal configurations in the atmospheric boundary layer. The analysis is based on arc scan data from a Doppler wind lidar with one elevation angle and seven azimuth angles spanning 30° and focuses on an estimation of 10-min mean wind speed and direction. When flow is horizontally uniform, this approach can provide accurate wind measurements required for wind resource assessments in part because of its high resampling rate. Retrieved wind velocities at a single range gate exhibit good correlation to data from a sonic anemometer on a nearby meteorological tower, and vertical profiles of horizontal wind speed, though derived from range gates located on a conical surface, match those measured by mast-mounted cup anemometers. Uncertainties in the retrieved wind velocity are related to high turbulent wind fluctuation and an inhomogeneous horizontal wind field. Moreover, the radial velocity variance is found to be a robust measure of the uncertainty of the retrieved wind speed because of its relationship to turbulence properties. It is further shown that the standard error of wind speed estimates can be minimized by increasing the azimuthal range beyond 30° and using five to seven azimuth angles.

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

    SciTech Connect (OSTI)

    Not Available

    2012-04-01

    NREL researchers have used high-tech instruments and high-performance computing to understand atmospheric turbulence and turbine wake behavior in order to improve wind turbine design and siting within wind farms.

  8. 20th Century Reanalysis Project Ensemble Gateway: 56 Estimates of World Temperature, Pressure, Humidity, and Wind, 1871-2010

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    This site provides data from the 20th Century Reanalysis Project, offering temperature, pressure, humidity, and wind predictions in 200 km sections all around the earth from 1871 to 2010, every 6 hours, based on historical data. The ensemble mean and standard deviation for each value were calculated over a set of 56 simulations. Data for each of the 56 ensemble members are included here. The dataset consists of files in netCDF 4 format that are available for download from the National Energy Research. The goal of the 20th Century Reanalysis Project is to use a Kalman filter-based technique to produce a global trophospheric circulation dataset at four-times-daily resolution back to 1871. The only dataset available for the early 20th century consists of error-ridden hand-drawn analyses of the mean sea level pressure field over the Northern Hemisphere. Modern data assimilation systems have the potential to improve upon these maps, but prior to 1948, few digitized upper-air sounding observations are available for such a reanalysis. The global tropospheric circulation dataset will provide an important validation check on the climate models used to make 21st century climate projections....[copied from http://portal.nersc.gov/project/20C_Reanalysis/

  9. STATIONARITY IN SOLAR WIND FLOWS

    SciTech Connect (OSTI)

    Perri, S.; Balogh, A. E-mail: a.balogh@imperial.ac.u

    2010-05-01

    By using single-point measurements in space physics it is possible to study a phenomenon only as a function of time. This means that we cannot have direct access to information about spatial variations of a measured quantity. However, the investigation of the properties of turbulence and of related phenomena in the solar wind widely makes use of an approximation frequently adopted in hydrodynamics under certain conditions, the so-called Taylor hypothesis; indeed, the solar wind flow has a bulk velocity along the radial direction which is much higher than the velocity of a single turbulent eddy embedded in the main flow. This implies that the time of evolution of the turbulent features is longer than the transit time of the flow through the spacecraft position, so that the turbulent field can be considered frozen into the solar wind flow. This assumption allows one to easily associate time variations with spatial variations and stationarity to homogeneity. We have investigated, applying criteria for weak stationarity to Ulysses magnetic field data in different solar wind regimes, at which timescale and under which conditions the hypothesis of stationarity, and then of homogeneity, of turbulence in the solar wind is well justified. We extend the conclusions of previous studies by Matthaeus and Goldstein to different parameter ranges in the solar wind. We conclude that the stationarity assumption in the inertial range of turbulence on timescales of 10 minutes to 1 day is reasonably satisfied in fast and uniform solar wind flows, but that in mixed, interacting fast, and slow solar wind streams the assumption is frequently only marginally valid.

  10. Wavenumber spectrum of whistler turbulence: Particle-in-cell simulation

    SciTech Connect (OSTI)

    Saito, S.; Gary, S. Peter; Narita, Y.

    2010-12-15

    The forward cascade of decaying whistler turbulence is studied in low beta plasma to understand essential properties of the energy spectrum at electron scales, by using a two-dimensional electromagnetic particle-in-cell (PIC) simulation. This simulation demonstrates turbulence in which the energy cascade rate is greater than the dissipation rate at the electron inertial length. The PIC simulation shows that the magnetic energy spectrum of forward-cascaded whistler turbulence at electron inertial scales is anisotropic and develops a very steep power-law spectrum which is consistent with recent solar wind observations. A comparison of the simulated spectrum with that predicted by a phenomenological turbulence scaling model suggests that the energy cascade at the electron inertial scale depends on both magnetic fluctuations and electron velocity fluctuations, as well as on the whistler dispersion relation. Thus, not only kinetic Alfven turbulence but also whistler turbulence may explain recent solar wind observations of very steep magnetic spectra at short scales.

  11. Turbulent equipartitions in two dimensional drift convection

    SciTech Connect (OSTI)

    Isichenko, M.B.; Yankov, V.V.

    1995-07-25

    Unlike the thermodynamic equipartition of energy in conservative systems, turbulent equipartitions (TEP) describe strongly non-equilibrium systems such as turbulent plasmas. In turbulent systems, energy is no longer a good invariant, but one can utilize the conservation of other quantities, such as adiabatic invariants, frozen-in magnetic flux, entropy, or combination thereof, in order to derive new, turbulent quasi-equilibria. These TEP equilibria assume various forms, but in general they sustain spatially inhomogeneous distributions of the usual thermodynamic quantities such as density or temperature. This mechanism explains the effects of particle and energy pinch in tokamaks. The analysis of the relaxed states caused by turbulent mixing is based on the existence of Lagrangian invariants (quantities constant along fluid-particle or other orbits). A turbulent equipartition corresponds to the spatially uniform distribution of relevant Lagrangian invariants. The existence of such turbulent equilibria is demonstrated in the simple model of two dimensional electrostatically turbulent plasma in an inhomogeneous magnetic field. The turbulence is prescribed, and the turbulent transport is assumed to be much stronger than the classical collisional transport. The simplicity of the model makes it possible to derive the equations describing the relaxation to the TEP state in several limits.

  12. Decades of Wind Turbine Load Simulation

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

    Decades of Wind Turbine Load Simulation Matthew Barone ∗ , Joshua Paquette † , Brian Resor ‡ Sandia National Laboratories § , Albuquerque, NM 87185 Lance Manuel ¶ University of Texas, Austin, TX 78712 A high-performance computer was used to simulate ninety-six years of operation of a five megawatt wind turbine. Over five million aero-elastic simulations were performed, with each simulation consisting of wind turbine operation for a ten minute period in turbulent wind conditions. These

  13. NREL Studies Wind Farm Aerodynamics to Improve Siting (Fact Sheet), Innovation Impact: Wind, NREL (National Renewable Energy Laboratory)

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

    Studies Wind Farm Aerodynamics to Improve Siting NREL researchers are using advanced remote sensing instruments and high- performance computing to understand atmospheric turbulence and turbine wake behavior-a key to improving wind turbine design and siting within wind farms. As turbines and wind farms grow in size, they create bigger wakes and present more complex challenges to wind turbine and wind farm designers and operators. NREL researchers have confirmed through both observation and

  14. West Winds Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    Winds Wind Farm Jump to: navigation, search Name West Winds Wind Farm Facility West Winds Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner...

  15. Turbulent Combustion

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

    Combustion - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Energy Defense Waste Management Programs Advanced Nuclear Energy

  16. Wind Electrolysis: Hydrogen Cost Optimization

    SciTech Connect (OSTI)

    Saur, G.; Ramsden, T.

    2011-05-01

    This report describes a hydrogen production cost analysis of a collection of optimized central wind based water electrolysis production facilities. The basic modeled wind electrolysis facility includes a number of low temperature electrolyzers and a co-located wind farm encompassing a number of 3MW wind turbines that provide electricity for the electrolyzer units.

  17. Scaling laws in magnetized plasma turbulence

    SciTech Connect (OSTI)

    Boldyrev, Stanislav

    2015-06-28

    wind, solar corona heating, and planetary magnetospheres; strong MHD turbulence, which is relevant for fusion devices, star formation, cosmic rays acceleration, scattering and trapping in galaxies, as well as many aspects of dynamics, distribution and composition of space plasmas, and the process of magnetic dynamo action, which explains the generation and the structure of magnetic fields in turbulent plasmas. The planned work will aim at developing new analytic approaches, conducting new numerical simulations with currently unmatched resolution, and training students in the methods of the modern theory of plasma turbulence. The work will be performed at the University of Wisconsin--Madison.

  18. ASYMMETRIC ELECTRON DISTRIBUTIONS IN THE SOLAR WIND

    SciTech Connect (OSTI)

    Rha, Kicheol; Ryu, Chang-Mo [Department of Physics, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)] [Department of Physics, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Yoon, Peter H. [Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742 (United States)] [Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742 (United States)

    2013-09-20

    A plausible mechanism responsible for producing asymmetric electron velocity distribution functions in the solar wind is investigated by means of one-dimensional electrostatic particle-in-cell (PIC) simulation. A recent paper suggests that the variation in the ion-to-electron temperature ratio influences the nonlinear wave-particle dynamics such that it results in the formation of asymmetric distributions. The present PIC code simulation largely confirms this finding, but quantitative differences between the weak turbulence formalism and the present PIC simulation are also found, suggesting the limitation of the analytical method. The inter-relationship between the asymmetric electron distribution and the ion-to-electron temperature ratio may be a new useful concept for the observation.

  19. ION HEATING IN INHOMOGENEOUS EXPANDING SOLAR WIND PLASMA: THE ROLE OF PARALLEL AND OBLIQUE ION-CYCLOTRON WAVES

    SciTech Connect (OSTI)

    Ozak, N.; Ofman, L.; Viñas, A.-F.

    2015-01-20

    Remote sensing observations of coronal holes show that heavy ions are hotter than protons and their temperature is anisotropic. In-situ observations of fast solar wind streams provide direct evidence for turbulent Alfvén wave spectrum, left-hand polarized ion-cyclotron waves, and He{sup ++} - proton drift in the solar wind plasma, which can produce temperature anisotropies by resonant absorption and perpendicular heating of the ions. Furthermore, the solar wind is expected to be inhomogeneous on decreasing scales approaching the Sun. We study the heating of solar wind ions in inhomogeneous plasma with a 2.5D hybrid code. We include the expansion of the solar wind in an inhomogeneous plasma background, combined with the effects of a turbulent wave spectrum of Alfvénic fluctuations and initial ion-proton drifts. We study the influence of these effects on the perpendicular ion heating and cooling and on the spectrum of the magnetic fluctuations in the inhomogeneous background wind. We find that inhomogeneities in the plasma lead to enhanced heating compared to the homogenous solar wind, and the generation of significant power of oblique waves in the solar wind plasma. The cooling effect due to the expansion is not significant for super-Alfvénic drifts, and is diminished further when we include an inhomogeneous background density. We reproduce the ion temperature anisotropy seen in observations and previous models, which is present regardless of the perpendicular cooling due to solar wind expansion. We conclude that small scale inhomogeneities in the inner heliosphere can significantly affect resonant wave ion heating.

  20. Rotationally sampled wind characteristics and correlations with MOD-OA wind turbine response

    SciTech Connect (OSTI)

    George, R.L.; Connell, J.R.

    1984-09-01

    This report presents results of a comprehensive wind and wind turbine measurement program: the Clayton, New Mexico, vertical plane array/MOD-OA project. In this experiment, the turbulent wind was measured for a large array of fixed anemometers located two blade diameters upwind of a 200-kW horizontal-axis wind turbine (HAWT). Simultaneously, key wind turbine response parameters were also measured. The first of two major objectives of this experiment was to determine the turbulent wind, rotationally sampled to emulate the motion of the wind turbine blade, for the range of different wind speeds and stability classes actually experienced by the wind turbine. The second major objective was to correlate this rotationally sampled wind with the wind turbine blade stress and power, in order to assess the usefulness of the wind measurements for wind turbine loads testing a prediction. Time series of rotationally sampled winds and wind turbine blade bending moments and power were converted to frequency spectra using Fourier transform techniques. These spectra were used as the basis for both qualitative and quantitative comparisons among the various cases. A quantitative comparison between the rotationally sampled wind input and blade bending response was made, using the Fourier spectra to estimate the blade transfer function. These transfer functions were then used to calculate an approximate damping coefficient for the MOD-OA fiberglass blade.

  1. Renaissance for wind power

    SciTech Connect (OSTI)

    Flavin, C.

    1981-10-01

    Wind research and development during the 1970s and recent studies showing wind to be a feasible source of both electrical and mechanical power are behind the rapid expansion of wind energy. Improved technology should make wind energy economical in most countries having sufficient wind and appropriate needs. A form of solar energy, winds form a large pattern of global air circulation because the earth's rotation causes differences in pressure and oceans cause differences in temperature. New development in the ancient art of windmill making date to the 1973 oil embargo, but wind availability must be determined at local sites to determine feasibility. Whether design features of the new technology and the concept of large wind farms will be incorporated in national energy policies will depend on changing attitudes, acceptance by utilities, and the speed with which new information is developed and disseminated. 44 references, 6 figures. (DCK)

  2. Wind Integration

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

    Wind Generation - ScheduledActual Balancing Reserves - Deployed Near Real-time Wind Animation Wind Projects under Review Growth Forecast Fact Sheets Working together to address...

  3. Prairie Winds Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    Wind Farm Jump to: navigation, search Name Prairie Winds Wind Farm Facility Prairie Winds Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner...

  4. Effects of Changing Atmospheric Conditions on Wind Turbine Performance (Poster)

    SciTech Connect (OSTI)

    Clifton, A.

    2012-12-01

    Multi-megawatt, utility-scale wind turbines operate in turbulent and dynamic winds that impact turbine performance in ways that are gradually becoming better understood. This poster presents a study made using a turbulent flow field simulator (TurbSim) and a Turbine aeroelastic simulator (FAST) of the response of a generic 1.5 MW wind turbine to changing inflow. The turbine power output is found to be most sensitive to wind speed and turbulence intensity, but the relationship depends on the wind speed with respect to the turbine's rated wind speed. Shear is found to be poorly correlated to power. A machine learning method called 'regression trees' is used to create a simple model of turbine performance that could be used as part of the wind resource assessment process. This study has used simple flow fields and should be extended to more complex flows, and validated with field observations.

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

    SciTech Connect (OSTI)

    George, R.L.

    1984-02-01

    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.

  6. THE ORIGIN OF NON-MAXWELLIAN SOLAR WIND ELECTRON VELOCITY DISTRIBUTION FUNCTION: CONNECTION TO NANOFLARES IN THE SOLAR CORONA

    SciTech Connect (OSTI)

    Che, H.; Goldstein, M. L.

    2014-11-10

    The formation of the observed core-halo feature in the solar wind electron velocity distribution function is a long-time puzzle. In this Letter, based on the current knowledge of nanoflares, we show that the nanoflare-accelerated electron beams are likely to trigger a strong electron two-stream instability that generates kinetic Alfvn wave and whistler wave turbulence, as we demonstrated in a previous paper. We further show that the core-halo feature produced during the origin of kinetic turbulence is likely to originate in the inner corona and can be preserved as the solar wind escapes to space along open field lines. We formulate a set of equations to describe the heating processes observed in the simulation and show that the core-halo temperature ratio of the solar wind is insensitive to the initial conditions in the corona and is related to the core-halo density ratio of the solar wind and to the quasi-saturation property of the two-stream instability at the time when the exponential decay ends. This relation can be extended to the more general core-halo-strahl feature in the solar wind. The temperature ratio between the core and hot components is nearly independent of the heliospheric distance to the Sun. We show that the core-halo relative drift previously reported is a relic of the fully saturated two-stream instability. Our theoretical results are consistent with the observations while new tests for this model are provided.

  7. THE NONLINEAR AND NONLOCAL LINK BETWEEN MACROSCOPIC ALFVNIC AND MICROSCOPIC ELECTROSTATIC SCALES IN THE SOLAR WIND

    SciTech Connect (OSTI)

    Valentini, F.; Vecchio, A.; Donato, S.; Carbone, V.; Veltri, P.; Briand, C.; Bougeret, J.

    2014-06-10

    The local heating of the solar-wind gas during its expansion represents one of the most intriguing problems in space plasma physics and is at present the subject of a relevant scientific effort. The possible mechanisms that could account for local heat production in the interplanetary medium are most likely related to the turbulent character of the solar-wind plasma. Nowadays, many observational and numerical analyses are devoted to the identification of fluctuation channels along which energy is carried from large to short wavelengths during the development of the turbulent cascade; these fluctuation channels establish the link between macroscopic and microscopic scales. In this Letter, by means of a quantitative comparison between in situ measurements in the solar wind from the STEREO spacecraft and numerical results from kinetic simulations, we identify an electrostatic channel of fluctuations that develops along the turbulent cascade in a direction parallel to the ambient magnetic field. This channel appears to be efficient in transferring the energy from large Alfvnic to short electrostatic acoustic-like scales up to a range of wavelengths where it can finally be turned into heat, even when the electron to proton temperature ratio is of the order of unity.

  8. NREL: Wind Research - NREL's WIND Toolkit Provides the Data Needed...

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

    by the numerical model. Barometric pressure, wind speed and direction (at 100 m above ground level), relative humidity, temperature, and air density data are available via an...

  9. Turbulence-chemistry interactions in reacting flows

    SciTech Connect (OSTI)

    Barlow, R.S.; Carter, C.D.

    1993-12-01

    Interactions between turbulence and chemistry in nonpremixed flames are investigated through multiscalar measurements. Simultaneous point measurements of major species, NO, OH, temperature, and mixture fraction are obtained by combining spontaneous Raman scattering, Rayleigh scattering, and laser-induced fluorescence (LIF). NO and OH fluorescence signals are converted to quantitative concentrations by applying shot-to-shot corrections for local variations of the Boltzmann fraction and collisional quenching rate. These measurements of instantaneous thermochemical states in turbulent flames provide insights into the fundamental nature of turbulence-chemistry interactions. The measurements also constitute a unique data base for evaluation and refinement of turbulent combustion models. Experimental work during the past year has focused on three areas: (1) investigation of the effects of differential molecular diffusion in turbulent combustion: (2) experiments on the effects of Halon CF{sub 3}Br, a fire retardant, on the structure of turbulent flames of CH{sub 4} and CO/H{sub 2}/N{sub 2}; and (3) experiments on NO formation in turbulent hydrogen jet flames.

  10. Wind Simulation

    Energy Science and Technology Software Center (OSTI)

    2008-12-31

    The Software consists of a spreadsheet written in Microsoft Excel that provides an hourly simulation of a wind energy system, which includes a calculation of wind turbine output as a power-curve fit of wind speed.

  11. Offshore Wind

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

    ... HomeStationary PowerEnergy Conversion EfficiencyWind EnergyOffshore Wind Offshore Wind Tara Camacho-Lopez 2016-0... March 2014, Barcelona, Spain, PO 225. Griffith, D.T., and ...

  12. Assessment of Combustion and Turbulence Models for the Simulation of

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

    Combustion Processes in a DI Diesel Engine | Department of Energy Combustion and Turbulence Models for the Simulation of Combustion Processes in a DI Diesel Engine Assessment of Combustion and Turbulence Models for the Simulation of Combustion Processes in a DI Diesel Engine Various applied combustion and turbulence models were investigated along with chemical kinetic mechanisms simulating a biodiesel-fueled engine deer09_ren.pdf (497.22 KB) More Documents & Publications Low Temperature

  13. Doppler Lidar Wind Value-Added Product (Technical Report) | SciTech...

    Office of Scientific and Technical Information (OSTI)

    Wind Value-Added Product Citation Details In-Document Search Title: Doppler Lidar Wind Value-Added Product Wind speed and direction, together with pressure, temperature, and ...

  14. 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

  15. Wind News

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

    ... laboratory mission technologies and ... By admin| ... participating in the Wind Turbine Radar Interference ... Association AWEA WindPower 2015 event in Orlando, Florida. ...

  16. Radiosonde measurements of turbulence

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

    Turbulence detection on aerial platforms using orientation sensors R. Giles Harrison, Robin J. Hogan, George W. Rogers, Alyssa M. Heath and Keri A. Nicoll Department of Meteorology University of Reading, UK r.g.harrison@reading.ac.uk 2 "Bumpiness" (or turbulence), still remains an aircraft hazard, even at cruising altitudes How can in-situ direct position and orientation sensing can be used to detect turbulence affecting aerial platforms? * Investigated using balloon platforms,

  17. Applied Turbulent Combustion

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

    ... Furthermore, combined spontaneous Raman spectroscopy, Rayleigh scatter, and OHCO-laser-induced fluorescence measurements have been used to quantify in situ turbulent flame mixture ...

  18. Daytime turbulent exchange between the Amazon forest and the atmosphere

    SciTech Connect (OSTI)

    Fitzjarrald, D.R.; Moore, K.E. ); Cabral, M.R. ); Scolar, J. ); Manzi, A.O.; de Abreau Sa, L.D. )

    1990-09-20

    Detailed observations of turbulence just above and below the crown of the Amazon rain forest during the wet season are presented. The forest canopy is shown to remove high-frequency turbulent fluctuations while passing lower frequencies. Filter characteristics of turbulent transfer into the Amazon rain forest canopy are quantified. In spite of the ubiquitous presence of clouds and frequent rain during this season, the average horizontal wind speed spectrum and the relationship between the horizontal wind speed and its standard deviation are well described by dry convective boundary layer similarity hypotheses originally found to apply in flat terrain. Diurnal changes in the sign of the vertical velocity skewness observed above and inside the canopy are shown to be plausibly explained by considering the skewness budget. Simple empirical formulas that relate observed turbulent heat fluxes to horizontal wind speed and variance are presented. Changes in the amount of turbulent coupling between the forest and the boundary layer associated with deep convective clouds are presented in three case studies. Even small raining clouds are capable of evacuating the canopy of substances normally trapped by persistent static stability near the forest floor. Recovery from these events can take more than an hour, even during midday.

  19. Core density turbulence in the HSX Stellarator

    SciTech Connect (OSTI)

    Deng, C. B.; Brower, D. L.; Anderson, D. T.; Anderson, F. S. B.; Briesemeister, Alexis R.; Likin, K. M.

    2015-10-23

    Broadband turbulent density fluctuations are explored in the helically symmetric stellarator experiment (HSX) by investigating changes related to plasma heating power and location. No fluctuation response is observed to occur with large changes in electron temperature and its gradient, thereby eliminating temperature gradient as a driving mechanism. Instead, measurements reveal that density turbulence varies inversely with electron density scale length. This response is consistent with density gradient drive as one might expect for trapped electron mode (TEM) turbulence. In general, the plasma stored energy and particle confinement are higher for discharges with reduced fluctuations in the plasma core. When the density fluctuation amplitude is reduced, increased plasma rotation is also evident suggesting a role is being played by intrinsic plasma flow.

  20. DNS/LES of Complex Turbulent Flows | Argonne Leadership Computing Facility

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

    Autoignition of a turbulent hydrogen jet injected into hot oxygen Autoignition of a turbulent hydrogen jet injected into hot oxygen. The green isocontours illustrate the turbulent structures in the fuel, the blue isocontours show the HO2 radical (an important precursor to autoignition), and the orange isosurfaces illustrate temperature. Credit: Rajapadiyan Asaithambi and Krishnan Mahesh, University of Minnesota DNS/LES of Complex Turbulent Flows PI Name: Krishnan Mahesh PI Email: mahesh@umn.edu

  1. Turbulent natural and mixed convection along a vertical plate

    SciTech Connect (OSTI)

    Abu-Mulaweh, H.I.; Armaly, B.F.; Chen, T.S.; Zhao, J.Z.

    1997-07-01

    Measurements of turbulent boundary-layer air flow in natural and mixed convection adjacent to an isothermal vertical flat plate are reported. Laser-Doppler velocimeter and cold wire anemometer were used, respectively, to measure simultaneously the mean turbulent velocity and temperature distributions were measured for a temperature difference, {Delta}T, of 30 C between the heated wall and the free stream air at a fixed location x = 3 m (with a corresponding Grashof number Gr{sub x} = 8.55 x 10{sup 10}), and for a range of free stream velocities 0 m/s {le} U{sub {infinity} } {le} 0.41 m/s. The effect of small free stream velocity on the turbulent natural convection is examined. These results reveal that the introduction of small free stream velocity on turbulent natural convection flow suppresses turbulence and decreases the heat transfer rate from the heated wall.

  2. Passively cooled direct drive wind turbine

    DOE Patents [OSTI]

    Costin, Daniel P.

    2008-03-18

    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.

  3. Aleutian Pribilof Islands Association - Wind Energy Development

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

    In the Aleutian Pribilof Islands Tribal Energy Program Review November 18, 2008 By Bruce Wright Connie Fredenberg Aleutian Pribilof Islands Association "The Birthplace of the Wind" Aleutian Pribilof Islands Association, Inc. * 150 mph gusts * Extreme Turbulence Potential * Corrosive Salt Spray World Class Wind: A Mixed Blessing Aleutian Pribilof Islands Association, Inc. LOGISTICS * Anchorage to Nikolski is 916 air miles for $1,316 rt. * During the fishing season a refundable ticket

  4. Upstream Measurements of Wind Profiles with Doppler Lidar for Improved Wind Energy Integration

    SciTech Connect (OSTI)

    Rodney Frehlich

    2012-10-30

    New upstream measurements of wind profiles over the altitude range of wind turbines will be produced using a scanning Doppler lidar. These long range high quality measurements will provide improved wind power forecasts for wind energy integration into the power grid. The main goal of the project is to develop the optimal Doppler lidar operating parameters and data processing algorithms for improved wind energy integration by enhancing the wind power forecasts in the 30 to 60 minute time frame, especially for the large wind power ramps. Currently, there is very little upstream data at large wind farms, especially accurate wind profiles over the full height of the turbine blades. The potential of scanning Doppler lidar will be determined by rigorous computer modeling and evaluation of actual Doppler lidar data from the WindTracer system produced by Lockheed Martin Coherent Technologies, Inc. of Louisville, Colorado. Various data products will be investigated for input into numerical weather prediction models and statistically based nowcasting algorithms. Successful implementation of the proposed research will provide the required information for a full cost benefit analysis of the improved forecasts of wind power for energy integration as well as the added benefit of high quality wind and turbulence information for optimal control of the wind turbines at large wind farms.

  5. NREL Develops New Controls that Proactively Adapt to the Wind (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2012-11-01

    Until now, wind turbine controls that reduce the impacts of wind gusts and turbulence were always reactive-responding to the wind rather than anticipating it. But with today's laser-based sensors that measure wind speed ahead of the turbine, researchers at the National Renewable Energy Laboratory (NREL) and their industry partners are developing more intelligent controls. The world's first field tests of these controls are currently underway at the National Wind Technology Center (NWTC) at NREL, with plans for future commercialization.

  6. NREL Develops New Controls that Proactively Adapt to the Wind (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2012-10-01

    Until now, wind turbine controls that reduce the impacts of wind gusts and turbulence were always reactive -- responding to the wind rather than anticipating it. But with today's laser-based sensors that measure wind speed ahead of the turbine, researchers at the National Renewable Energy Laboratory (NREL) and their industry partners are developing more intelligent controls. The world's first field tests of these controls are currently underway at the National Wind Technology Center (NWTC) at NREL, with plans for future commercialization.

  7. Cisco Wind Energy Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    Cisco Wind Energy Wind Farm Jump to: navigation, search Name Cisco Wind Energy Wind Farm Facility Cisco Wind Energy Sector Wind energy Facility Type Commercial Scale Wind Facility...

  8. Wind Easements

    Broader source: Energy.gov [DOE]

    The statutes authorizing the creation of wind easements include several provisions to protect property owners. For example, a wind easement may not make the property owner liable for any property...

  9. Wind Farm

    Broader source: Energy.gov [DOE]

    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...

  10. 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 Mountains, about 50-60 miles southwest. The numeric grid values indicate wind potential, with a range from 1 (poor) to 7 (superb). Just inside Texas in the southern Guadalupe Mountains, the Delaware Mountain Wind Power Facility in Culbertson County, Texas currently generates over 30 MW, and could be expanded to a 250 MW

  11. Observations of Edge Turbulence

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

    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...

  12. Free energy balance in gyrokinetic turbulence

    SciTech Connect (OSTI)

    Banon Navarro, A.; Morel, P.; Albrecht-Marc, M.; Carati, D.; Merz, F.; Goerler, T.; Jenko, F.

    2011-09-15

    Free energy plays an important role in gyrokinetic theory, since it is known to be a nonlinear invariant. Its evolution equations are derived and analyzed for the case of ion temperature gradient driven turbulence, using the formalism adopted in the Gene code. In particular, the ion temperature gradient drive, the collisional dissipation as well as entropy/electrostatic energy transfer channels represented by linear curvature and parallel terms are analyzed in detail.

  13. Boundary Plasma Turbulence Simulations for Tokamaks

    SciTech Connect (OSTI)

    Xu, X; Umansky, M; Dudson, B; Snyder, P

    2008-05-15

    The boundary plasma turbulence code BOUT models tokamak boundary-plasma turbulence in a realistic divertor geometry using modified Braginskii equations for plasma vorticity, density (ni), electron and ion temperature (T{sub e}; T{sub i}) and parallel momenta. The BOUT code solves for the plasma fluid equations in a three dimensional (3D) toroidal segment (or a toroidal wedge), including the region somewhat inside the separatrix and extending into the scrape-off layer; the private flux region is also included. In this paper, a description is given of the sophisticated physical models, innovative numerical algorithms, and modern software design used to simulate edge-plasmas in magnetic fusion energy devices. The BOUT code's unique capabilities and functionality are exemplified via simulations of the impact of plasma density on tokamak edge turbulence and blob dynamics.

  14. NO concentration imaging in turbulent nonpremixed flames

    SciTech Connect (OSTI)

    Schefer, R.W.

    1993-12-01

    The importance of NO as a pollutant species is well known. An understanding of the formation characteristics of NO in turbulent hydrocarbon flames is important to both the desired reduction of pollutant emissions and the validation of proposed models for turbulent reacting flows. Of particular interest is the relationship between NO formation and the local flame zone, in which the fuel is oxidized and primary heat release occurs. Planar imaging of NO provides the multipoint statistics needed to relate NO formation to the both the flame zone and the local turbulence characteristics. Planar imaging of NO has been demonstrated in turbulent flames where NO was seeded into the flow at high concentrations (2000 ppm) to determine the gas temperature distribution. The NO concentrations in these experiments were significantly higher than those expected in typical hydrocarbon-air flames, which require a much lower detectability limit for NO measurements. An imaging technique based on laser-induced fluorescence with sufficient sensitivity to study the NO formation mechanism in the stabilization region of turbulent lifted-jet methane flames.

  15. Combustion-turbulence interaction in the turbulent boundary layer over a hot surface

    SciTech Connect (OSTI)

    Ng, T.T.; Cheng, R.K.; Robben, F.; Talbot, L.

    1982-01-01

    The turbulence-combustion interaction in a reacting turbulent boundary layer over a heated flat plate was studied. Ethylene/air mixture with equivalence ratio of 0.35 was used. The free stream velocity was 10.5 m/s and the wall temperature was 1250/sup 0/K. Combustion structures visualization was provided by high-speed schlieren photographs. Fluid density statistics were deduced from Rayleigh scattering intensity measurements. A single-component laser Doppler velocimetry system was used to obtain mean and root-mean-square velocity distributions, the Reynolds stress, the streamwise and the cross-stream turbulent kinetic energy diffusion, and the production of turbulent kinetic energy by Reynolds stress. The combustion process was dominated by large-scale turbulent structures of the boundary layer. Combustion causes expansion of the boundary layer. No overall self-similarity is observed in either the velocity or the density profiles. Velocity fluctuations were increased in part of the boundary layer and the Reynolds stress was reduced. The turbulent kinetic energy diffusion pattern was changed significantly and a modification of the boundary layer assumption will be needed when dealing with this problem analytically. 11 figures, 1 table.

  16. Statistical and Spectral Analysis of Wind Characteristics Relevant to Wind Energy Assessment Using Tower Measurements in Complex Terrain

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

    Belu, Radian; Koracin, Darko

    2013-01-01

    The main objective of the study was to investigate spatial and temporal characteristics of the wind speed and direction in complex terrain that are relevant to wind energy assessment and development, as well as to wind energy system operation, management, and grid integration. Wind data from five tall meteorological towers located in Western Nevada, USA, operated from August 2003 to March 2008, used in the analysis. The multiannual average wind speeds did not show significant increased trend with increasing elevation, while the turbulence intensity slowly decreased with an increase were the average wind speed. The wind speed and direction weremore » modeled using the Weibull and the von Mises distribution functions. The correlations show a strong coherence between the wind speed and direction with slowly decreasing amplitude of the multiday periodicity with increasing lag periods. The spectral analysis shows significant annual periodicity with similar characteristics at all locations. The relatively high correlations between the towers and small range of the computed turbulence intensity indicate that wind variability is dominated by the regional synoptic processes. Knowledge and information about daily, seasonal, and annual wind periodicities are very important for wind energy resource assessment, wind power plant operation, management, and grid integration.« less

  17. Coalescing Wind Turbine Wakes

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

    Lee, S.; Churchfield, M.; Sirnivas, S.; Moriarty, P.; Nielsen, F. G.; Skaare, B.; Byklum, E.

    2015-06-18

    A team of researchers from the National Renewable Energy Laboratory and Statoil used large-eddy simulations to numerically investigate the merging wakes from upstream offshore wind turbines. Merging wakes are typical phenomena in wind farm flows in which neighboring turbine wakes consolidate to form complex flow patterns that are as yet not well understood. In the present study, three 6-MW turbines in a row were subjected to a neutrally stable atmospheric boundary layer flow. As a result, the wake from the farthest upstream turbine conjoined the downstream wake, which significantly altered the subsequent velocity deficit structures, turbulence intensity, and the globalmore » meandering behavior. The complexity increased even more when the combined wakes from the two upstream turbines mixed with the wake generated by the last turbine, thereby forming a "triplet" structure. Although the influence of the wake generated by the first turbine decayed with downstream distance, the mutated wakes from the second turbine continued to influence the downstream wake. Two mirror-image angles of wind directions that yielded partial wakes impinging on the downstream turbines yielded asymmetric wake profiles that could be attributed to the changing flow directions in the rotor plane induced by the Coriolis force. In conclusion, the turbine wakes persisted for extended distances in the present study, which is a result of low aerodynamic surface roughness typically found in offshore conditions« less

  18. Coalescing Wind Turbine Wakes

    SciTech Connect (OSTI)

    Lee, S.; Churchfield, M.; Sirnivas, S.; Moriarty, P.; Nielsen, F. G.; Skaare, B.; Byklum, E.

    2015-06-18

    A team of researchers from the National Renewable Energy Laboratory and Statoil used large-eddy simulations to numerically investigate the merging wakes from upstream offshore wind turbines. Merging wakes are typical phenomena in wind farm flows in which neighboring turbine wakes consolidate to form complex flow patterns that are as yet not well understood. In the present study, three 6-MW turbines in a row were subjected to a neutrally stable atmospheric boundary layer flow. As a result, the wake from the farthest upstream turbine conjoined the downstream wake, which significantly altered the subsequent velocity deficit structures, turbulence intensity, and the global meandering behavior. The complexity increased even more when the combined wakes from the two upstream turbines mixed with the wake generated by the last turbine, thereby forming a "triplet" structure. Although the influence of the wake generated by the first turbine decayed with downstream distance, the mutated wakes from the second turbine continued to influence the downstream wake. Two mirror-image angles of wind directions that yielded partial wakes impinging on the downstream turbines yielded asymmetric wake profiles that could be attributed to the changing flow directions in the rotor plane induced by the Coriolis force. In conclusion, the turbine wakes persisted for extended distances in the present study, which is a result of low aerodynamic surface roughness typically found in offshore conditions

  19. Passive Acoustic Detection of Wind Turbine In-Flow Conditions for Active Control and Optimization

    SciTech Connect (OSTI)

    Murray, Nathan E.

    2012-03-12

    Wind is a significant source of energy; however, the human capability to produce electrical energy still has many hurdles to overcome. One of these is the unpredictability of the winds in the atmospheric boundary layer (ABL). The ABL is highly turbulent in both stable and unstable conditions (based on the vertical temperature profile) and the resulting fluctuations can have a dramatic impact on wind turbine operation. Any method by which these fluctuations could be observed, estimated, or predicted could provide a benefit to the wind energy industry as a whole. Based on the fundamental coupling of velocity fluctuations to pressure fluctuations in the nearly incompressible flow in the ABL, This work hypothesizes that a ground-based array of infrasonic pressure transducers could be employed to estimate the vertical wind profile over a height relevant for wind turbines. To analyze this hypothesis, experiments and field deployments were conducted. Wind tunnel experiments were performed for a thick turbulent boundary layer over a neutral or heated surface. Surface pressure and velocity probe measurements were acquired simultaneously. Two field deployments yielded surface pressure data from a 49 element array. The second deployment at the Reese Technology Center in Lubbock, TX, also included data from a smaller aperture, 96-element array and a 200-meter tall meteorological tower. Analysis of the data successfully demonstrated the ability to estimate the vertical velocity profile using coherence data from the pressure array. Also, dynamical systems analysis methods were successful in identifying and tracking a gust type event. In addition to the passive acoustic profiling method, this program also investigated a rapid response Doppler SODAR system, the optimization of wind turbine blades for enhanced power with reduced aeroacoustic noise production, and the implementation of a wireless health monitoring system for the wind turbine blades. Each of these other objectives

  20. ARM - Measurement - Atmospheric turbulence

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

    for Environment Prediction Global Forecast System RUC : Rapid Update Cycle Model Data WPDN : Wind Profiler Demo Network Field Campaign Instruments AIRCRAFTCABIN : Aircraft Cabin ...

  1. SCALING PROPERTIES OF SMALL-SCALE FLUCTUATIONS IN MAGNETOHYDRODYNAMIC TURBULENCE

    SciTech Connect (OSTI)

    Perez, Jean Carlos; Mason, Joanne; Boldyrev, Stanislav; Cattaneo, Fausto E-mail: j.mason@exeter.ac.uk E-mail: cattaneo@flash.uchicago.edu

    2014-09-20

    Magnetohydrodynamic (MHD) turbulence in the majority of natural systems, including the interstellar medium, the solar corona, and the solar wind, has Reynolds numbers far exceeding the Reynolds numbers achievable in numerical experiments. Much attention is therefore drawn to the universal scaling properties of small-scale fluctuations, which can be reliably measured in the simulations and then extrapolated to astrophysical scales. However, in contrast with hydrodynamic turbulence, where the universal structure of the inertial and dissipation intervals is described by the Kolmogorov self-similarity, the scaling for MHD turbulence cannot be established based solely on dimensional arguments due to the presence of an intrinsic velocity scale—the Alfvén velocity. In this Letter, we demonstrate that the Kolmogorov first self-similarity hypothesis cannot be formulated for MHD turbulence in the same way it is formulated for the hydrodynamic case. Besides profound consequences for the analytical consideration, this also imposes stringent conditions on numerical studies of MHD turbulence. In contrast with the hydrodynamic case, the discretization scale in numerical simulations of MHD turbulence should decrease faster than the dissipation scale, in order for the simulations to remain resolved as the Reynolds number increases.

  2. Wind Workshop

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

    Department of Energy Wind Turbine Manufacturing Transforms with Three-Dimensional Printing Wind Turbine Manufacturing Transforms with Three-Dimensional Printing May 19, 2016 - 12:57pm Addthis From medical devices to airplane components, three-dimensional (3-D) printing (also called additive manufacturing) is transforming the manufacturing industry. Now, research that supports the Energy Department's Atmosphere to Electrons (A2e) initiative is applying 3-D-printing processes to create wind

  3. Wind News

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

    Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & ...

  4. Wind Energy

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

    Stationary Power/Energy Conversion Efficiency/Wind Energy Wind Energy Tara Camacho-Lopez 2016-08-30T20:56:10+00:00 Increasing the viability of wind energy technology by applying research to improve wind turbine performance and reliability http://windworkshops.sandia.gov/ Rotor Innovation Advancing rotor technology such that they capture more energy, more reliably, with relatively lower system loads-all at a lower end cost. SWiFT Facility & Testing Improving the performance and reducing the

  5. Wind Power Forecasting Data

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

    Operations Call 2012 Retrospective Reports 2012 Retrospective Reports 2011 Smart Grid Wind Integration Wind Integration Initiatives Wind Power Forecasting Wind Projects Email...

  6. NREL: Wind Research - Wind Career Map Shows Wind Industry Career...

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

    Wind Career Map Shows Wind Industry Career Opportunities, Paths A screenshot of the wind career map showing the various points on a chart that show different careers in the wind...

  7. Stetson Wind Expansion Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    Stetson Wind Expansion Wind Farm Jump to: navigation, search Name Stetson Wind Expansion Wind Farm Facility Stetson Wind Expansion Sector Wind energy Facility Type Commercial Scale...

  8. State Fair Wind Energy Education Center Wind Farm | Open Energy...

    Open Energy Info (EERE)

    Fair Wind Energy Education Center Wind Farm Jump to: navigation, search Name State Fair Wind Energy Education Center Wind Farm Facility Wind Energy Education Center Sector Wind...

  9. Wind Power Partners '94 Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    4 Wind Farm Jump to: navigation, search Name Wind Power Partners '94 Wind Farm Facility Wind Power Partners '94 Sector Wind energy Facility Type Commercial Scale Wind Facility...

  10. Wethersfield Wind Power Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    Wethersfield Wind Power Wind Farm Jump to: navigation, search Name Wethersfield Wind Power Wind Farm Facility Wethersfield Wind Power Sector Wind energy Facility Type Commercial...

  11. Portsmouth Abbey School Wind Turbine Wind Farm | Open Energy...

    Open Energy Info (EERE)

    Abbey School Wind Turbine Wind Farm Jump to: navigation, search Name Portsmouth Abbey School Wind Turbine Wind Farm Facility Portsmouth Abbey School Wind Turbine Sector Wind energy...

  12. Harbec Plastic Wind Turbine Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    Harbec Plastic Wind Turbine Wind Farm Jump to: navigation, search Name Harbec Plastic Wind Turbine Wind Farm Facility Harbec Plastic Wind Turbine Sector Wind energy Facility Type...

  13. NREL: Wind Research - Offshore Wind Research

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

    NREL's Offshore Wind Testing Capabilities 35 years of wind turbine testing experience ... Testing Applying 35 years of wind turbine testing expertise, NREL has developed ...

  14. NREL: Wind Research - Small Wind Turbine Development

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

    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 ...

  15. NREL: Wind Research - Offshore Wind Resource Characterization

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

    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 ...

  16. RF wave propagation and scattering in turbulent tokamak plasmas

    SciTech Connect (OSTI)

    Horton, W. Michoski, C.; Peysson, Y.; Decker, J.

    2015-12-10

    Drift wave turbulence driven by the steep electron and ion temperature gradients in H-mode divertor tokamaks produce scattering of the RF waves used for heating and current drive. The X-ray emission spectra produced by the fast electrons require the turbulence broaden RF wave spectrum. Both the 5 GHz Lower Hybrid waves and the 170 GHz electron cyclotron [EC] RF waves experience scattering and diffraction by the electron density fluctuations. With strong LHCD there are bifurcations in the coupled turbulent transport dynamics giving improved steady-state confinement states. The stochastic scattering of the RF rays makes the prediction of the distribution of the rays and the associated particle heating a statistical problem. Thus, we introduce a Fokker-Planck equation for the probably density of the RF rays. The general frame work of the coupled system of coupled high frequency current driving rays with the low-frequency turbulent transport determines the profiles of the plasma density and temperatures.

  17. OBSERVATION OF FLUX-TUBE CROSSINGS IN THE SOLAR WIND

    SciTech Connect (OSTI)

    Arnold, L.; Li, G.; Li, X.; Yan, Y.

    2013-03-20

    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.

  18. Danielson Wind | Open Energy Information

    Open Energy Info (EERE)

    Wind Jump to: navigation, search Name Danielson Wind Facility Danielson Wind Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Developer Juhl Wind...

  19. Kawailoa Wind | Open Energy Information

    Open Energy Info (EERE)

    Wind Jump to: navigation, search Name Kawailoa Wind Facility Kawailoa Wind Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner First Wind...

  20. Palouse Wind | Open Energy Information

    Open Energy Info (EERE)

    Wind Jump to: navigation, search Name Palouse Wind Facility Palouse Wind Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner First Wind...

  1. Harbor Wind | Open Energy Information

    Open Energy Info (EERE)

    Wind Jump to: navigation, search Name Harbor Wind Facility Harbor Wind Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner Harbor Wind LLC...

  2. Kahuku Wind | Open Energy Information

    Open Energy Info (EERE)

    Kahuku Wind Jump to: navigation, search Name Kahuku Wind Facility Kahuku Wind Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner First Wind...

  3. Wiota Wind | Open Energy Information

    Open Energy Info (EERE)

    Wiota Wind Jump to: navigation, search Name Wiota Wind Facility Wiota Wind Sector Wind energy Facility Type Community Wind Facility Status In Service Owner Wiota Wind Energy LLC...

  4. Bravo Wind | Open Energy Information

    Open Energy Info (EERE)

    Bravo Wind Jump to: navigation, search Name Bravo Wind Facility Bravo Wind Sector Wind energy Facility Type Commercial Scale Wind Facility Status Proposed Developer Bravo Wind LLC...

  5. Auwahi Wind | Open Energy Information

    Open Energy Info (EERE)

    Auwahi Wind Jump to: navigation, search Name Auwahi Wind Facility Auwahi Wind Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner BP Wind Energy...

  6. Traer Wind | Open Energy Information

    Open Energy Info (EERE)

    Traer Wind Jump to: navigation, search Name Traer Wind Facility Traer Wind Sector Wind energy Facility Type Community Wind Facility Status In Service Owner Norsemen Wind Energy LLC...

  7. Sheffield Wind | Open Energy Information

    Open Energy Info (EERE)

    Wind Jump to: navigation, search Name Sheffield Wind Facility Sheffield Wind Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner First Wind...

  8. Rollins Wind | Open Energy Information

    Open Energy Info (EERE)

    Wind Jump to: navigation, search Name Rollins Wind Facility Rollins Wind Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner First Wind...

  9. MAGNETIC HELICITY IN THE DISSIPATION RANGE OF STRONG IMBALANCED TURBULENCE

    SciTech Connect (OSTI)

    Markovskii, S. A.; Vasquez, Bernard J. E-mail: bernie.vasquez@unh.edu

    2013-05-01

    Hybrid numerical simulations of freely decaying two-dimensional turbulence are presented. The background magnetic field is perpendicular to the simulation plane, which eliminates linear kinetic Alfven waves from the system. The net magnetic helicity of the initial fluctuations at large scales is zero. The turbulence is set to be imbalanced in the sense that the net cross-helicity is not zero. 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. The peak position depends on the plasma beta and correlates with a sharp decline of the cross-helicity spectrum.

  10. 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.

  11. 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...

  12. Predicting aerodynamic characteristic of typical wind turbine airfoils using CFD

    SciTech Connect (OSTI)

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

    1997-09-01

    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.

  13. Offshore Wind Power USA

    Broader source: Energy.gov [DOE]

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

  14. Wind Energy

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

    Wind Energy The DTU SpinnerLidar installed in the nacelle of the SWiFT facility A1 turbine Permalink Gallery First Wake Data Captured During Wake Steering Experiment at the SWiFT Facility News, Renewable Energy, SWIFT, Wind Energy, Wind News First Wake Data Captured During Wake Steering Experiment at the SWiFT Facility Researchers at Sandia National Laboratories and the National Renewable Energy Laboratory (NREL) have met a major project milestone as part of the Department of Energy Atmosphere

  15. Spatial confinement of the IBEX Ribbon: A dominant turbulence mechanism

    SciTech Connect (OSTI)

    Isenberg, Philip A.

    2014-05-20

    The narrow ribbon of enhanced energetic neutral atom flux observed by the Interstellar Boundary Explorer spacecraft has prompted numerous ideas to explain its structure and properties. One of these ideas is the 'neutral solar wind' scenario, which identifies the source particles as pickup protons in the local interstellar medium originating in solar wind charge-exchange interactions. This scenario has been thought to require unrealistically weak pitch-angle scattering of the pickup protons to explain the narrow structure. Recently, Schwadron and McComas suggested that this structure could result from a spatial retention of the pickup protons, rather than from a restricted pitch-angle distribution. Here, we present a physically motivated, quantitative mechanism to produce such a spatial configuration. This mechanism is based on the 'dominant turbulence' assumption, which can be applied where the production of new pickup protons is slow, and has been used to successfully explain the level of turbulent heating observed in the outer solar wind. This formalism predicts a pickup isotropization process which adds or subtracts energy from the ambient turbulent fluctuations, depending on the initial pitch angle of the pickup protons. We show that a simple model of this process can yield a ribbon structure in qualitative agreement with the observations. The results of this simple model are not yet quantitatively satisfactory, but we suggest several improvements which may reduce the quantitative discrepancy.

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

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

    Rate Retrievals ProductsCloud-Scale Vertical Velocity and Turbulent Dissipation Rate Retrievals 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 PI Product : Cloud-Scale Vertical Velocity and Turbulent Dissipation Rate Retrievals 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

  17. WINDExchange: Selling Wind Power

    Wind Powering America (EERE)

    Market Sectors Printable Version Bookmark and Share Utility-Scale Wind Distributed Wind Motivations for Buying Wind Power Buying Wind Power Selling Wind Power Selling Wind Power Owners of wind turbines interconnected directly to the transmission or distribution grid, or that produce more power than the host consumes, can sell wind power as well as other generation attributes. Wind-Generated Electricity Electricity generated by wind turbines can be used to cover on-site energy needs

  18. UNDERSTANDING GALAXY OUTFLOWS AS THE PRODUCT OF UNSTABLE TURBULENT SUPPORT

    SciTech Connect (OSTI)

    Scannapieco, Evan

    2013-02-01

    The interstellar medium is a multiphase gas in which turbulent support is as important as thermal pressure. Sustaining this configuration requires both continuous turbulent stirring and continuous radiative cooling to match the decay of turbulent energy. While this equilibrium can persist for small turbulent velocities, if the one-dimensional velocity dispersion is larger than Almost-Equal-To 35 km s{sup -1}, the gas moves into an unstable regime that leads to rapid heating. I study the implications of this turbulent runaway, showing that it causes a hot gas outflow to form in all galaxies with a gas surface density above Almost-Equal-To 50 M{sub Sun} pc{sup -2}, corresponding to a star formation rate per unit area of Almost-Equal-To 0.1 M{sub Sun} yr{sup -1} kpc{sup -2}. For galaxies with v{sub esc} {approx}> 200 km s{sup -1}, the sonic point of this hot outflow should lie interior to the region containing cold gas and stars, while for galaxies with smaller escape velocities, the sonic point should lie outside this region. This leads to efficient cold cloud acceleration in higher mass galaxies, while in lower mass galaxies, clouds may be ejected by random turbulent motions rather than accelerated by the wind. Finally, I show that energy balance cannot be achieved at all for turbulent media above a surface density of Almost-Equal-To 10{sup 5} M{sub Sun} pc{sup -2}.

  19. GYROKINETIC PARTICLE SIMULATION OF TURBULENT TRANSPORT IN BURNING PLASMAS

    SciTech Connect (OSTI)

    Horton, Claude Wendell

    2014-06-10

    The SciDAC project at the IFS advanced the state of high performance computing for turbulent structures and turbulent transport. The team project with Prof Zhihong Lin [PI] at Univ California Irvine produced new understanding of the turbulent electron transport. The simulations were performed at the Texas Advanced Computer Center TACC and the NERSC facility by Wendell Horton, Lee Leonard and the IFS Graduate Students working in that group. The research included a Validation of the electron turbulent transport code using the data from a steady state university experiment at the University of Columbia in which detailed probe measurements of the turbulence in steady state were used for wide range of temperature gradients to compare with the simulation data. These results were published in a joint paper with Texas graduate student Dr. Xiangrong Fu using the work in his PhD dissertation. X.R. Fu, W. Horton, Y. Xiao, Z. Lin, A.K. Sen and V. Sokolov, “Validation of electron Temperature gradient turbulence in the Columbia Linear Machine, Phys. Plasmas 19, 032303 (2012).

  20. Mesoscale and Large-Eddy Simulations for Wind Energy

    SciTech Connect (OSTI)

    Marjanovic, N

    2011-02-22

    Operational wind power forecasting, turbine micrositing, and turbine design require high-resolution simulations of atmospheric flow over complex terrain. The use of both Reynolds-Averaged Navier Stokes (RANS) and large-eddy (LES) simulations is explored for wind energy applications using the Weather Research and Forecasting (WRF) model. To adequately resolve terrain and turbulence in the atmospheric boundary layer, grid nesting is used to refine the grid from mesoscale to finer scales. This paper examines the performance of the grid nesting configuration, turbulence closures, and resolution (up to as fine as 100 m horizontal spacing) for simulations of synoptically and locally driven wind ramping events at a West Coast North American wind farm. Interestingly, little improvement is found when using higher resolution simulations or better resolved turbulence closures in comparison to observation data available for this particular site. This is true for week-long simulations as well, where finer resolution runs show only small changes in the distribution of wind speeds or turbulence intensities. It appears that the relatively simple topography of this site is adequately resolved by all model grids (even as coarse as 2.7 km) so that all resolutions are able to model the physics at similar accuracy. The accuracy of the results is shown in this paper to be more dependent on the parameterization of the land-surface characteristics such as soil moisture rather than on grid resolution.

  1. Nebraska wind resource assessment first year results

    SciTech Connect (OSTI)

    Hurley, P.J.F.; Vilhauer, R.; Stooksbury, D.

    1996-12-31

    This paper presents the preliminary results from a wind resource assessment program in Nebraska sponsored by the Nebraska Power Association. During the first year the measured annual wind speed at 40 meters ranged from 6.5 - 7.5 m/s (14.6 - 16.8 mph) at eight stations across the state. The site selection process is discussed as well as an overview of the site characteristics at the monitoring locations. Results from the first year monitoring period including data recovery rate, directionality, average wind speeds, wind shear, and turbulence intensity are presented. Results from the eight sites are qualitatively compared with other midwest and west coast locations. 5 figs., 2 tabs.

  2. Milford Wind Corridor Phase I (Clipper) Wind Farm | Open Energy...

    Open Energy Info (EERE)

    Clipper) Wind Farm Jump to: navigation, search Name Milford Wind Corridor Phase I (Clipper) Wind Farm Facility Milford Wind Corridor Phase I (Clipper) Sector Wind energy Facility...

  3. Dynamic stall on wind turbine blades

    SciTech Connect (OSTI)

    Butterfield, C.P.; Simms, D.; Scott, G. ); Hansen, A.C. )

    1991-12-01

    Dynamic loads must be predicted accurately in order to estimate the fatigue life of wind turbines operating in turbulent environments. Dynamic stall contributes to increased dynamic loads during normal operation of all types of horizontal-axis wind turbine (HAWTs). This report illustrates how dynamic stall varies throughout the blade span of a 10 m HAWT during yawed and unyawed operating conditions. Lift, drag, and pitching moment coefficients during dynamics stall are discussed. Resulting dynamic loads are presented, and the effects of dynamic stall on yaw loads are demonstrated using a yaw loads dynamic analysis (YAWDYN). 12 refs., 22 figs., 1 tab.

  4. ELECTRONIC BIVANE WIND DIRECTION INDICATOR

    DOE Patents [OSTI]

    Moses, H.

    1961-05-01

    An apparatus is described for determining and recording three dimensional wind vectors. The apparatus comprises a rotatably mounted azimuthal wind component sensing head and an elevational wind component sensing head mounted to the azimuthal head and adapted to rotate therewith in the azimuthal plane and independently in the elevational plane. A heat source and thermocouples disposed thereabout are mounted within each of the sensing heads, the thermocouples providing electrical signals responsive to the temperature differential created by the passage of air through the sensing tuhes. The thermocouple signals are applied to drive mechanisms which position the sensing heads to a null wind position. Recording means are provided responsive to positional data from the drive mechanisms which are a measurement of the three dimensional wind vectors.

  5. THE EFFICIENCY OF SECOND-ORDER FERMI ACCELERATION BY WEAKLY COMPRESSIBLE MAGNETOHYDRODYNAMIC TURBULENCE

    SciTech Connect (OSTI)

    Lynn, Jacob W.; Quataert, Eliot; Parrish, Ian J.; Chandran, Benjamin D. G.

    2013-11-10

    We investigate the effects of pitch-angle scattering on the efficiency of particle heating and acceleration by MHD turbulence using phenomenological estimates and simulations of non-relativistic test particles interacting with strong, subsonic MHD turbulence. We include an imposed pitch-angle scattering rate, which is meant to approximate the effects of high-frequency plasma waves and/or velocity space instabilities. We focus on plasma parameters similar to those found in the near-Earth solar wind, though most of our results are more broadly applicable. An important control parameter is the size of the particle mean free path ?{sub mfp} relative to the scale of the turbulent fluctuations L. For small scattering rates, particles interact quasi-resonantly with turbulent fluctuations in magnetic field strength. Scattering increases the long-term efficiency of this resonant heating by factors of a few times 10, but the distribution function does not develop a significant non-thermal power-law tail. For higher scattering rates, the interaction between particles and turbulent fluctuations becomes non-resonant, governed by particles heating and cooling adiabatically as they encounter turbulent density fluctuations. Rapid pitch-angle scattering can produce a power-law tail in the proton distribution function, but this requires fine-tuning of parameters. Moreover, in the near-Earth solar wind, a significant power-law tail cannot develop by this mechanism because the particle acceleration timescales are longer than the adiabatic cooling timescale set by the expansion of the solar wind. Our results thus imply that MHD-scale turbulent fluctuations are unlikely to be the origin of the v {sup 5} tail in the proton distribution function observed in the solar wind.

  6. Aleutian Pribilof Islands Wind Energy Feasibility Study

    SciTech Connect (OSTI)

    Bruce A. Wright

    2012-03-27

    Under this project, the Aleutian Pribilof Islands Association (APIA) conducted wind feasibility studies for Adak, False Pass, Nikolski, Sand Point and St. George. The DOE funds were also be used to continue APIA's role as project coordinator, to expand the communication network quality between all participants and with other wind interest groups in the state and to provide continued education and training opportunities for regional participants. This DOE project began 09/01/2005. We completed the economic and technical feasibility studies for Adak. These were funded by the Alaska Energy Authority. Both wind and hydro appear to be viable renewable energy options for Adak. In False Pass the wind resource is generally good but the site has high turbulence. This would require special care with turbine selection and operations. False Pass may be more suitable for a tidal project. APIA is funded to complete a False Pass tidal feasibility study in 2012. Nikolski has superb potential for wind power development with Class 7 wind power density, moderate wind shear, bi-directional winds and low turbulence. APIA secured nearly $1M from the United States Department of Agriculture Rural Utilities Service Assistance to Rural Communities with Extremely High Energy Costs to install a 65kW wind turbine. The measured average power density and wind speed at Sand Point measured at 20m (66ft), are 424 W/m2 and 6.7 m/s (14.9 mph) respectively. Two 500kW Vestas turbines were installed and when fully integrated in 2012 are expected to provide a cost effective and clean source of electricity, reduce overall diesel fuel consumption estimated at 130,000 gallons/year and decrease air emissions associated with the consumption of diesel fuel. St. George Island has a Class 7 wind resource, which is superior for wind power development. The current strategy, led by Alaska Energy Authority, is to upgrade the St. George electrical distribution system and power plant. Avian studies in Nikolski and

  7. JD Wind 6 Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    JD Wind 6 Wind Farm Jump to: navigation, search Name JD Wind 6 Wind Farm Facility JD Wind 6 Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner...

  8. JD Wind 7 Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    JD Wind 7 Wind Farm Jump to: navigation, search Name JD Wind 7 Wind Farm Facility JD Wind 7 Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner...

  9. Metro Wind LLC Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    Wind LLC Wind Farm Jump to: navigation, search Name Metro Wind LLC Wind Farm Facility Metro Wind LLC Sector Wind energy Facility Type Commercial Scale Wind Facility Status In...

  10. Michigan Wind II Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    II Wind Farm Jump to: navigation, search Name Michigan Wind II Wind Farm Facility Michigan Wind II Wind Farm Sector Wind energy Facility Type Commercial Scale Wind Facility Status...

  11. Characteristics study of Transmission Line Mechanical Research Center (TLMRC) wind tower data. Notes on field-wind loading experiments

    SciTech Connect (OSTI)

    Shan, L.

    1992-10-01

    To initiate and develop EPRI`s wind loading research program, an experimental wind tower was erected at the TLMRC site. A number of anemometers were placed at different elevation levels of the wind tower. Strain gages were also mounted on the leg posts of the tower. The purposes of this experiment were to establish the wind characteristics at the TLMRC site, and to gain experience using different types of instrumentation and data acquisition techniques in field-wind loading experiments. Three sets of wind data collected from the TLMRC wind tower were validated and analyzed in this study. Since the characteristics of wind and response data can be described in different terms and by various methods, the study describes the concept, Identifies the focal point, and discusses the results of each method used in this report. In addition, some comments are provided on how to conduct the field-wind loading experiments as well as how to analyze the wind and response data. The results of this study show that: (1) the magnitudes of wind velocity and direction can vary considerably during a short period of time; (2) the mean vertical wind profile does not hold constant as usually assumed; (3) the turbulence intensity and the gust factor increase as the height above ground decreases; (4) the averaging time can greatly influence the results of wind data analysis; (5) although wind contains lime energy beyond 1 Hz, structural responses above 1 Hz can be excited; (6) strong relationships exist between the wind velocity and the responses in the leg posts of the wind tower. System identification, a tool for establishing models of dynamic systems based in observed data, is successfully used in a trial application which estimates the relationship between the wind velocity and the responses in the wind tower.

  12. Garnet Wind | Open Energy Information

    Open Energy Info (EERE)

    Wind Jump to: navigation, search Name Garnet Wind Facility Garnet Wind Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner Azusa Light & Water...

  13. Lime Wind | Open Energy Information

    Open Energy Info (EERE)

    Wind Jump to: navigation, search Name Lime Wind Facility Lime Wind Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner Joseph Millworks Inc...

  14. Fairhaven Wind | Open Energy Information

    Open Energy Info (EERE)

    Wind Jump to: navigation, search Name Fairhaven Wind Facility Fairhaven Wind Sector Wind energy Facility Type Community Wind Facility Status In Service Owner Solaya Energy Palmer...

  15. Scituate Wind | Open Energy Information

    Open Energy Info (EERE)

    Wind Jump to: navigation, search Name Scituate Wind Facility Scituate Wind Sector Wind energy Facility Type Community Wind Facility Status In Service Owner Solaya Energy ...

  16. Pacific Wind | Open Energy Information

    Open Energy Info (EERE)

    Wind Jump to: navigation, search Name Pacific Wind Facility Pacific Wind Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner enXco Developer...

  17. Galactic Wind | Open Energy Information

    Open Energy Info (EERE)

    Wind Jump to: navigation, search Name Galactic Wind Facility Galactic Wind Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner Epic Systems...

  18. Rockland Wind | Open Energy Information

    Open Energy Info (EERE)

    Wind Jump to: navigation, search Name Rockland Wind Facility Rockland Wind Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Developer Ridgeline...

  19. Greenfield Wind | Open Energy Information

    Open Energy Info (EERE)

    Jump to: navigation, search Name Greenfield Wind Facility Greenfield Wind Sector Wind energy Facility Type Community Wind Facility Status In Service Owner Greenfield Wind Power...

  20. Willmar Wind | Open Energy Information

    Open Energy Info (EERE)

    Wind Jump to: navigation, search Name Willmar Wind Facility Willmar Wind Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner Willmar...

  1. NREL: Innovation Impact - Wind

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

    Wind Energy Menu Home Home Solar Solar Wind Wind Analysis Analysis Bioenergy Bioenergy Buildings Buildings Transportation Transportation Manufacturing Manufacturing Energy Systems ...

  2. Energy 101: Wind Turbines

    ScienceCinema (OSTI)

    None

    2013-05-29

    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.

  3. Wind Program News

    SciTech Connect (OSTI)

    2012-01-06

    Stay current on the news about the wind side of the Wind and Water Power Program and important wind energy events around the U.S.

  4. Wind turbine

    DOE Patents [OSTI]

    Cheney, Jr., Marvin C.

    1982-01-01

    A wind turbine of the type having an airfoil blade (15) mounted on a flexible beam (20) and a pitch governor (55) which selectively, torsionally twists the flexible beam in response to wind turbine speed thereby setting blade pitch, is provided with a limiter (85) which restricts unwanted pitch change at operating speeds due to torsional creep of the flexible beam. The limiter allows twisting of the beam by the governor under excessive wind velocity conditions to orient the blades in stall pitch positions, thereby preventing overspeed operation of the turbine. In the preferred embodiment, the pitch governor comprises a pendulum (65,70) which responds to changing rotor speed by pivotal movement, the limiter comprising a resilient member (90) which engages an end of the pendulum to restrict further movement thereof, and in turn restrict beam creep and unwanted blade pitch misadjustment.

  5. One-dimensional turbulence modeling of a turbulent counterflow flame with comparison to DNS

    SciTech Connect (OSTI)

    Jozefik, Zoltan; Kerstein, Alan R.; Schmidt, Heiko; Lyra, Sgouria; Kolla, Hemanth; Chen, Jackie H.

    2015-06-01

    The one-dimensional turbulence (ODT) model is applied to a reactant-to-product counterflow configuration and results are compared with DNS data. The model employed herein solves conservation equations for momentum, energy, and species on a one dimensional (1D) domain corresponding to the line spanning the domain between nozzle orifice centers. The effects of turbulent mixing are modeled via a stochastic process, while the Kolmogorov and reactive length and time scales are explicitly resolved and a detailed chemical kinetic mechanism is used. Comparisons between model and DNS results for spatial mean and root-meansquare (RMS) velocity, temperature, and major and minor species profiles are shown. The ODT approach shows qualitatively and quantitatively reasonable agreement with the DNS data. Scatter plots and statistics conditioned on temperature are also compared for heat release rate and all species. ODT is able to capture the range of results depicted by DNS. However, conditional statistics show signs of underignition.

  6. Large Eddy Simulation of Stable Boundary Layer Turbulent Processes in Complex Terrain

    SciTech Connect (OSTI)

    Eric D. Skyllingstad

    2005-01-26

    Research was performed using a turbulence boundary layer model to study the behavior of cold, dense flows in regions of complex terrain. Results show that flows develop a balance between turbulent entrainment of warm ambient air and dense, cold air created by surface cooling. Flow depth and strength is a function of downslope distance, slope angle and angle changes, and the ambient air temperature.

  7. NREL: Wind Research - Site Wind Resource Characteristics

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

    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. ...

  8. NREL: Wind Research - Offshore Wind Turbine Research

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

    Offshore Wind Turbine Research Photo of a European offshore wind farm. Photo by Siemens For more than eight years, NREL has worked with the U.S. Department of Energy (DOE) to become an international leader in offshore wind energy research. NREL's offshore wind turbine research capabilities focus on critical areas that reflect the long-term needs of the industry and DOE. National Wind Technology Center (NWTC) researchers are perpetually exploring new wind and water power concepts, materials, and

  9. Evaluation of three lidar scanning strategies for turbulence measurements

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

    Newman, Jennifer F.; Klein, Petra M.; Wharton, Sonia; Sathe, Ameya; Bonin, Timothy A.; Chilson, Phillip B.; Muschinski, Andreas

    2016-05-03

    Several errors occur when a traditional Doppler beam swinging (DBS) or velocity–azimuth display (VAD) strategy is used to measure turbulence with a lidar. To mitigate some of these errors, a scanning strategy was recently developed which employs six beam positions to independently estimate the u, v, and w velocity variances and covariances. In order to assess the ability of these different scanning techniques to measure turbulence, a Halo scanning lidar, WindCube v2 pulsed lidar, and ZephIR continuous wave lidar were deployed at field sites in Oklahoma and Colorado with collocated sonic anemometers.Results indicate that the six-beam strategy mitigates some of the errors caused bymore » VAD and DBS scans, but the strategy is strongly affected by errors in the variance measured at the different beam positions. The ZephIR and WindCube lidars overestimated horizontal variance values by over 60 % under unstable conditions as a result of variance contamination, where additional variance components contaminate the true value of the variance. A correction method was developed for the WindCube lidar that uses variance calculated from the vertical beam position to reduce variance contamination in the u and v variance components. The correction method reduced WindCube variance estimates by over 20 % at both the Oklahoma and Colorado sites under unstable conditions, when variance contamination is largest. This correction method can be easily applied to other lidars that contain a vertical beam position and is a promising method for accurately estimating turbulence with commercially available lidars.« less

  10. Evaluation of three lidar scanning strategies for turbulence measurements

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

    Newman, J. F.; Klein, P. M.; Wharton, S.; Sathe, A.; Bonin, T. A.; Chilson, P. B.; Muschinski, A.

    2015-11-24

    Several errors occur when a traditional Doppler-beam swinging (DBS) or velocityazimuth display (VAD) strategy is used to measure turbulence with a lidar. To mitigate some of these errors, a scanning strategy was recently developed which employs six beam positions to independently estimate the u, v, and w velocity variances and covariances. In order to assess the ability of these different scanning techniques to measure turbulence, a Halo scanning lidar, WindCube v2 pulsed lidar and ZephIR continuous wave lidar were deployed at field sites in Oklahoma and Colorado with collocated sonic anemometers. Results indicate that the six-beam strategy mitigates somemoreof the errors caused by VAD and DBS scans, but the strategy is strongly affected by errors in the variance measured at the different beam positions. The ZephIR and WindCube lidars overestimated horizontal variance values by over 60 % under unstable conditions as a result of variance contamination, where additional variance components contaminate the true value of the variance. A correction method was developed for the WindCube lidar that uses variance calculated from the vertical beam position to reduce variance contamination in the u and v variance components. The correction method reduced WindCube variance estimates by over 20 % at both the Oklahoma and Colorado sites under unstable conditions, when variance contamination is largest. This correction method can be easily applied to other lidars that contain a vertical beam position and is a promising method for accurately estimating turbulence with commercially available lidars.less

  11. Advances in compressible turbulent mixing

    SciTech Connect (OSTI)

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

    1992-01-01

    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.

  12. Assessment of research needs for wind turbine rotor materials technology

    SciTech Connect (OSTI)

    Not Available

    1991-01-01

    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.

  13. Wind | Department of Energy

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

    Science & Innovation Energy Sources Renewable Energy Wind Wind Wind The United States is home to one of the largest and fastest growing wind markets in the world. To stay ...

  14. Wind speed power spectrum analysis for Bushland, Texas

    SciTech Connect (OSTI)

    Eggleston, E.D.

    1996-12-31

    Numerous papers and publications on wind turbulence have referenced the wind speed spectrum presented by Isaac Van der Hoven in his article entitled Power Spectrum of Horizontal Wind Speed Spectrum in the Frequency Range from 0.0007 to 900 Cycles per Hour. Van der Hoven used data measured at different heights between 91 and 125 meters above the ground, and represented the high frequency end of the spectrum with data from the peak hour of hurricane Connie. These facts suggest we should question the use of his power spectrum in the wind industry. During the USDA - Agricultural Research Service`s investigation of wind/diesel system power storage, using the appropriate wind speed power spectrum became a significant issue. We developed a power spectrum from 13 years of hourly average data, 1 year of 5 minute average data, and 2 particularly gusty day`s 1 second average data all collected at a height of 10 meters. While the general shape is similar to the Van der Hoven spectrum, few of his peaks were found in the Bushland spectrum. While higher average wind speeds tend to suggest higher amplitudes in the high frequency end of the spectrum, this is not always true. Also, the high frequency end of the spectrum is not accurately described by simple wind statistics such as standard deviation and turbulence intensity. 2 refs., 5 figs., 1 tab.

  15. NREL Software Models Performance of Wind Plants (Fact Sheet), NREL Highlights in Research & Development, NREL (National Renewable Energy Laboratory)

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

    Simulator fOr Wind Farm Applications helps optimize layouts and controls of wind plant arrays. In 2014, researchers from the National Renewable Energy Laboratory (NREL) launched the Simulator fOr Wind Farm Applications (SOWFA), a coupled open-source software package and framework that allows users to inves- tigate 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 turbine

  16. 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 ...

  17. NREL: Wind Research - Wind Resource Assessment

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

    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

  18. Wind Integration National Dataset (WIND) Toolkit

    Broader source: Energy.gov [DOE]

    For utility companies, grid operators and other stakeholders interested in wind energy integration, collecting large quantities of high quality data on wind energy resources is vitally important....

  19. Turbulence-Turbine Interaction: The Basis for the Development of the TurbSim Stochastic Simulator

    SciTech Connect (OSTI)

    Kelley, N. D.

    2011-11-01

    A combination of taller wind turbines with more flexible rotors and towers operating in turbulent conditions that are not well understood is contributing to much higher than anticipated maintenance and repairs costs and is associated with lower energy production. This report documents evidence of this and offers the turbine designers an expanded tool that resolves many of these shortcomings.

  20. Windmill wake turbulence decay: a preliminary theoretical model

    SciTech Connect (OSTI)

    Bossanyi, E.A.

    1983-02-01

    The results are given of initial theoretical attempts to predict dynamic wake characteristics, particularly turbulence decay, downstream of wind turbine generators in order to assess the potential for acoustic noise generation in clusters or arrays of turbines. These results must be considered preliminary, because the model described is at least partially based on the assumption of isotropy in the turbine wakes; however, anisotrpic conditions may actually exist, particularly in the near-wake regions. The results indicate that some excess spectral energy may still exist. The turbine-generated turbulence from one machine can reach the next machine in the cluster and, depending on the turbulent wavelengths critical for acoustic noise production and perhaps structural excitation, this may be a cause for concern. Such a situation is most likely to occur in the evening or morining, during the transition from the daytime to the nocturnal boundary layer and vice-versa, particularly at more elevated sites where the winds tend to increase after dark.

  1. GROWTH OF A LOCALIZED SEED MAGNETIC FIELD IN A TURBULENT MEDIUM

    SciTech Connect (OSTI)

    Cho, Jungyeon; Yoo, Hyunju

    2012-11-10

    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.

  2. Study of Nonlinear Interaction and Turbulence of Alfven Waves in LAPD Experiments

    SciTech Connect (OSTI)

    Boldyrev, Stanislav; Perez, Jean Carlos

    2013-11-29

    The complete project had two major goals — investigate MHD turbulence generated by counterpropagating Alfven modes, and study such processes in the LAPD device. In order to study MHD turbulence in numerical simulations, two codes have been used: full MHD, and reduced MHD developed specialy for this project. Quantitative numerical results are obtained through high-resolution simulations of strong MHD turbulence, performed through the 2010 DOE INCITE allocation. We addressed the questions of the spectrum of turbulence, its universality, and the value of the so-called Kolmogorov constant (the normalization coefficient of the spectrum). In these simulations we measured with unprecedented accuracy the energy spectra of magnetic and velocity fluctuations. We also studied the so-called residual energy, that is, the difference between kinetic and magnetic energies in turbulent fluctuations. In our analytic work we explained generation of residual energy in weak MHD turbulence, in the process of random collisions of counterpropagating Alfven waves. We then generalized these results for the case of strong MHD turbulence. The developed model explained generation of residual energy is strong MHD turbulence, and verified the results in numerical simulations. We then analyzed the imbalanced case, where more Alfven waves propagate in one direction. We found that spectral properties of the residual energy are similar for both balanced and imbalanced cases. We then compared strong MHD turbulence observed in the solar wind with turbulence generated in numerical simulations. Nonlinear interaction of Alfv´en waves has been studied in the upgraded Large Plasma Device (LAPD). We have simulated the collision of the Alfven modes in the settings close to the experiment. We have created a train of wave packets with the apltitudes closed to those observed n the experiment, and allowed them to collide. We then saw the generation of the second harmonic, resembling that observed in the

  3. Wind Energy

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

    2 - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Energy Defense Waste Management Programs Advanced Nuclear Energy Nuclear

  4. Wind Energy

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

    3 - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Energy Defense Waste Management Programs Advanced Nuclear Energy Nuclear

  5. Wind News

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

    Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Energy Defense Waste Management Programs Advanced Nuclear Energy Nuclear Energy

  6. wind turbines

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

    turbines - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Energy Defense Waste Management Programs Advanced Nuclear Energy

  7. Doppler Lidar Wind Value-Added Product

    SciTech Connect (OSTI)

    Newsom, R. K.; Sivaraman, C.; Shippert, T. R.; Riihimaki, L. D.

    2015-07-01

    Wind speed and direction, together with pressure, temperature, and relative humidity, are the most fundamental atmospheric state parameters. Accurate measurement of these parameters is crucial for numerical weather prediction. Vertically resolved wind measurements in the atmospheric boundary layer are particularly important for modeling pollutant and aerosol transport. Raw data from a scanning coherent Doppler lidar system can be processed to generate accurate height-resolved measurements of wind speed and direction in the atmospheric boundary layer.

  8. JD Wind 5 Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    5 Wind Farm Jump to: navigation, search Name JD Wind 5 Wind Farm Facility JD Wind 5 Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner John...

  9. Cow Branch Wind Energy Center Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    Cow Branch Wind Energy Center Wind Farm Jump to: navigation, search Name Cow Branch Wind Energy Center Wind Farm Facility Cow Branch Wind Energy Center Sector Wind energy Facility...

  10. JD Wind 4 Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    4 Wind Farm Jump to: navigation, search Name JD Wind 4 Wind Farm Facility JD Wind 4 Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner John...