scholarly journals Statistical Analysis of Inflow and Structural Response Data From the LIST Program

2003 ◽  
Author(s):  
Luke D. Nelson ◽  
Lance Manuel ◽  
Herbert J. Sutherland ◽  
Paul S. Veers
Keyword(s):  
Wind Speed ◽  
Sequential Analysis ◽  
Test List ◽  
Structural Response ◽  
Vertical Shear ◽  
Horizontal Wind ◽  
Parameter Vector ◽  
Time Data ◽  
Response Data ◽  
Extreme Load

The Long-Term Inflow and Structural Test (LIST) program is gathering inflow and structural response data on a modified version of the Micon 65/13 wind turbine at a test site near Bushland, Texas. Data from 491 ten-minute time data records are analyzed here to determine the dependency of fatigue and extreme loads on inflow parameters. Flap and edge bending moment ranges at a blade root are chosen as the structural response variable, z. Various parameters related to the inflow (including, for example, primary parameters, the mean and standard deviation of the hub-height horizontal wind speed, and secondary parameters, Reynolds stresses, vertical shear exponent, etc.) are each considered in an inflow parameter vector, x. Time series for the structural response, z, are processed in order to obtain a structural response parameter, y, where in separate statistical studies, y is taken to be either an equivalent fatigue load or an extreme load. This paper first describes a procedure by which the important “dependencies” of y on the various variables contained in the inflow parameter vector, x, may be determined considering all the available data. These dependencies of y on x are then recomputed using only the data with above-rated mean wind speeds (taken to be approximately 13 m/s). The procedure employed is similar to other previous studies, but we do not bin the data sets by wind speed since dependencies in one wind speed bin may be different from those in other bins. Also, our procedure, in sharp contrast to previous studies, examines each inflow parameter in the vector, x, in a sequential analysis, rather than by using multivariate regression.

Statistical Analysis of Wind Turbine Inflow and Structural Response Data from the LIST Program

2003 ◽  
Vol 125 (4) ◽  
pp. 541-550 ◽  
Author(s):  
Luke D. Nelson ◽  
Lance Manuel ◽  
Herbert J. Sutherland ◽  
Paul S. Veers
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Test List ◽  
Structural Response ◽  
Vertical Shear ◽  
Horizontal Wind ◽  
Parameter Vector ◽  
Response Data ◽  
Extreme Loads ◽  
Extreme Load

The Long-Term Inflow and Structural Test (LIST) program is gathering inflow and structural response data on a modified version of the Micon 65/13 wind turbine at a test site near Bushland, Texas. Data from 491 ten-minute time data records are analyzed here to determine the dependency of fatigue and extreme loads on inflow parameters. Flap and edge bending moment ranges at a blade root are chosen as the structural response variable, z. Various parameters related to the inflow (including, for example, primary parameters such as the mean and standard deviation of the hub-height horizontal wind speed, and secondary parameters such as Reynolds stresses, vertical shear exponent, etc.) are each considered in an inflow parameter vector, x. Time series for the structural response, z, are processed in order to obtain a structural response parameter, y, where in separate statistical studies, y is taken to be either an equivalent fatigue load or an extreme load. This study describes a procedure by which the important “dependencies” of y on the various variables contained in the inflow parameter vector, x, may be determined considering all the available data. These dependencies of y on x are then recomputed using only the data with above-rated mean wind speeds (taken to be approximately 13 m/s). The procedure employed is similar to other studies, but we do not bin the data sets by wind speed since dependencies in one wind speed bin may be different from those in other bins. Also, our procedure, in sharp contrast to previous studies, examines each inflow parameter in the vector, x, in a sequential analysis, rather than by using multivariate regression. Results from the present study suggest that the primary inflow parameters have a small amount of predictive power in establishing fatigue and extreme loads. In addition, large correlations that exist between several of the secondary parameters individually and each of the primary parameters make it difficult for the secondary parameters to provide any additional explanation of turbine response once the primary parameters have been accounted for.

A Comparison of Standard Coherence Models for Inflow Turbulence With Estimates from Field Measurements

2004 ◽  
Vol 126 (4) ◽  
pp. 1069-1082 ◽  
Author(s):  
Korn Saranyasoontorn ◽  
Lance Manuel ◽  
Paul S. Veers
Keyword(s):  
Single Point ◽  
Test List ◽  
Structural Response ◽  
Field Measurements ◽  
Horizontal Wind ◽  
International Electrotechnical Commission ◽  
Horizontal Wind Speed ◽  
Low Frequencies ◽  
Inflow Turbulence ◽  
Vertical Turbulence

The Long-term Inflow and Structural Test (LIST) program, managed by Sandia National Laboratories, Albuquerque, NM, is gathering inflow and structural response data on a modified version of the Micon 65/13 wind turbine at a site near Bushland, Texas. With the objective of establishing correlations between structural response and inflow, previous studies have employed regression and other dependency analyses to attempt to relate loads to various inflow parameters. With these inflow parameters that may be thought of as single-point-in-space statistics that ignore the spatial nature of the inflow, no significant correlation was identified between load levels and any single inflow parameter or even any set of such parameters, beyond the mean and standard deviation of the hub-height horizontal wind speed. Accordingly, here, we examine spatial statistics in the measured inflow of the LIST turbine by estimating the coherence for the three turbulence components (along-wind, across-wind, and vertical). We examine coherence spectra for both lateral and vertical separations and use the available ten-minute time series of the three components at several locations. The data obtained from spatial arrays on three main towers located upwind from the test turbine as well as on two additional towers on either side of the main towers consist of 291 ten-minute records. Details regarding estimation of the coherence functions from limited data are discussed. Comparisons with standard coherence models available in the literature and provided in the International Electrotechnical Commission (IEC) guidelines are also discussed. It is found that the Davenport exponential coherence model may not be appropriate especially for modeling the coherence of the vertical turbulence component since it fails to account for reductions in coherence at low frequencies and over large separations. Results also show that the Mann uniform shear turbulence model predicts coherence spectra for all turbulence components and for different lateral separations better than the isotropic von Ka´rma´n model. Finally, on studying the cross-coherence among pairs of turbulence components based on field data, it is found that the coherence observed between along-wind and vertical turbulence components is not predicted by the isotropic von Ka´rma´n model while the Mann model appears to overestimate this cross-coherence.

scholarly journals Turbulence parameters measured by the Beijing Mesosphere–Stratosphere–Troposphere radar in the troposphere/lower stratosphere with three models: Comparison and analyses

2022 ◽  
Author(s):  
Ze Chen ◽  
Yufang Tian ◽  
Yinan Wang ◽  
Yongheng Bi ◽  
Xue Wu ◽  
...  
Keyword(s):  
Wind Speed ◽  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Spectral Width ◽  
Vertical Shear ◽  
Horizontal Wind ◽  
Horizontal Wind Speed ◽  
Turbulence Parameters ◽  
2D Model ◽  
Calculation Models

Abstract. Based on the quality-controlled observational spectral width data of the Beijing Mesosphere–Stratosphere–Troposphere (MST) radar in the altitudinal range of 3–19.8 km from 2012 to 2014, this paper analyzes the relationship between the proportion of negative turbulent kinetic energy (N-TKE) and the horizontal wind speed/horizontal wind vertical shear domain, and gives the distributional characteristics of atmospheric turbulence parameters obtained by using different calculation models. Three calculation models of the spectral width method were used in this study—namely, the H model (Hocking, 1985), N-2D model (Nastrom, 1997) and D-H model (Dehghan and Hocking, 2011). The results showed that the proportion of N-TKE in the H model increases with the horizontal wind speed and/or the vertical shear of horizontal wind speed, up to 80 %. When the horizontal wind speed is greater than 40 m·s−1, the proportion of N-TKE in the H model is greater than 60 %, and thus the H model is not applicable. When the horizontal wind speed is greater than 20 m s−1, the proportion of N-TKE in the N-2D model and D-H model increases with the horizontal wind speed, independent of the vertical shear of the horizontal wind speed, and the maximum values are 2 % and 4 %, respectively. However, it is still necessary to consider the applicability of the N-2D model and D-H model in some weather processes with strong winds. The distributional characteristics with height of the turbulent kinetic energy dissipation rate 𝜀 and the vertical eddy diffusion coefficient Kz derived by the three models are consistent with previous studies. Still, there are differences in the values of turbulence parameters. Also, the range resolution of the radar has little effect on the differences in the range of turbulence parameters' values. The median values of 𝜀 in the H model, N-2D model and D-H model are 10−3.2–10−2.8 m2 s−3, 10−2.8–10−2.4 m2 s−3 and 10−3.0–10−2.5 m2 s−3, respectively. The median values of Kz in these three models are 100.18–100.67 m2 s−1, 100.57–100.90 m2 s−1 and 100.44–100.74 m2 s−1.

Analysis of the Structural and Inflow Data From the List Turbine

2002 ◽  
Vol 124 (4) ◽  
pp. 432-445 ◽  
Author(s):  
Herbert J. Sutherland
Keyword(s):  
Test List ◽  
Vertical Component ◽  
Structural Response ◽  
Horizontal Wind ◽  
Reynolds Stresses ◽  
Load Spectrum ◽  
Fatigue Load ◽  
Horizontal Wind Speed ◽  
Fatigue Loads

The Long-term Inflow and Structural Test (LIST) program is collecting long-term, continuous inflow and structural response data to characterize the spectrum of loads on wind turbines. A heavily instrumented Micon 65/13M turbine with Phoenix 8m blades is being used as the test turbine for the first measurement campaign of this program. This turbine is located in Bushland, TX, a test site that exposes the turbine to a wind regime representative of a Great Plains commercial site. The turbine and inflow are being characterized with 60 measurements: 34 to characterize the inflow, 19 to characterize structural response, and seven to characterize the time-varying state of the turbine. In this paper, an analysis of the structural and inflow data is presented. Particular attention is paid to the determination of the various structural loads on the turbine, long-term fatigue spectra and the correlation of various inflow descriptors with fatigue loads. For the latter analysis, the inflow is described by various parameters, including the mean, standard deviation, skewness and kurtosis of the hub-height horizontal wind speed, turbulence intensity, turbulence length scales, Reynolds stresses, local friction velocity, Obukhov length, and the gradient Richardson number. The fatigue load spectrum corresponding to these parameters is characterized as an equivalent fatigue load. A regression analysis is then used to determine which parameters are correlated to the fatigue loads. The results illustrate that the vertical component of the inflow is the most important of the secondary inflow parameters with respect to fatigue loads. Long-term fatigue spectra illustrate that extrapolation of relatively short-term data to longer times is consistent for the data reported here.

Inflow and Fatigue Response of the NWTC Advanced Research Turbine

2003 ◽  
Author(s):  
Herbert J. Sutherland ◽  
Neil D. Kelley ◽  
M. Maureen Hand
Keyword(s):  
Test List ◽  
Structural Response ◽  
Synchronous Generator ◽  
Measurement Unit ◽  
Response Data ◽  
Extreme Loads ◽  
Sonic Anemometers ◽  
Planar Array ◽  
Fatigue Loads

The Long-term Inflow and Structural Test (LIST) program is collecting long-term inflow and structural response data to characterize the spectrum of loads on wind turbines. In one of the measurement campaigns being conducted under this program, the 42-m diameter, 600-kW NWTC Advanced Research Turbine (ART) was monitored. The turbine is an upwind, two-bladed teetered-hub machine. It has full span pitch control and a synchronous generator. The inflow was monitored with a planar array of five high-resolution sonic anemometers and supporting meteorological instrumentation located 1.5 diameters upwind of the turbine. The structural response of the turbine was measured using strain gauge circuits and an inertial measurement unit (IMU). The former were used to monitor root bending moments and the low-speed shaft torque, while the latter was used to monitor the motion of the tower and the nacelle. Auxiliary gauges measured blade pitch, rotor teeter, nacelle yaw and generator power. A total of 3299 10-minute records were collected for analysis. From this set, 1044 records are used to examine the influence of various inflow parameters on fatigue loads. Long-term fatigue loads and extreme loads are also examined.

scholarly journals Winds in the Lower Cloud Level on the Nightside of Venus from VIRTIS-M (Venus Express) 1.74 μm Images

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 186
Author(s):  
Dmitry A. Gorinov ◽  
Ludmila V. Zasova ◽  
Igor V. Khatuntsev ◽  
Marina V. Patsaeva ◽  
Alexander V. Turin
Keyword(s):  
Wind Speed ◽  
Meridional Wind ◽  
Equatorial Region ◽  
Hadley Cell ◽  
Horizontal Wind ◽  
Simultaneous Increase ◽  
Volcanic Area ◽  
Infrared Thermal Imaging ◽  
Latitude Range ◽  
Lower Cloud

The horizontal wind velocity vectors at the lower cloud layer were retrieved by tracking the displacement of cloud features using the 1.74 µm images of the full Visible and InfraRed Thermal Imaging Spectrometer (VIRTIS-M) dataset. This layer was found to be in a superrotation mode with a westward mean speed of 60–63 m s−1 in the latitude range of 0–60° S, with a 1–5 m s−1 westward deceleration across the nightside. Meridional motion is significantly weaker, at 0–2 m s−1; it is equatorward at latitudes higher than 20° S, and changes its direction to poleward in the equatorial region with a simultaneous increase of wind speed. It was assumed that higher levels of the atmosphere are traced in the equatorial region and a fragment of the poleward branch of the direct lower cloud Hadley cell is observed. The fragment of the equatorward branch reveals itself in the middle latitudes. A diurnal variation of the meridional wind speed was found, as east of 21 h local time, the direction changes from equatorward to poleward in latitudes lower than 20° S. Significant correlation with surface topography was not found, except for a slight decrease of zonal wind speed, which was connected to the volcanic area of Imdr Regio.

scholarly journals On strongly nonlinear gravity waves in a vertically sheared atmosphere

2020 ◽  
Vol 6 (1) ◽  
pp. 63-74
Author(s):  
Mark Schlutow ◽  
Georg S. Voelker
Keyword(s):  
Gravity Waves ◽  
Lower Layer ◽  
Vertical Shear ◽  
Horizontal Wind ◽  
Necessary Condition ◽  
Mean Flow ◽  
Individual Layer ◽  
Strongly Nonlinear ◽  
The Mean ◽  
The Stability

Abstract We investigate strongly nonlinear stationary gravity waves which experience refraction due to a thin vertical shear layer of horizontal background wind. The velocity amplitude of the waves is of the same order of magnitude as the background flow and hence the self-induced mean flow alters the modulation properties to leading order. In this theoretical study, we show that the stability of such a refracted wave depends on the classical modulation stability criterion for each individual layer, above and below the shearing. Additionally, the stability is conditioned by novel instability criteria providing bounds on the mean-flow horizontal wind and the amplitude of the wave. A necessary condition for instability is that the mean-flow horizontal wind in the upper layer is stronger than the wind in the lower layer.

A Review on ANN Based Model for Solar Radiation and Wind Speed Prediction with Real-Time Data

2022 ◽  
Author(s):  
Pooja Malik ◽  
Anita Gehlot ◽  
Rajesh Singh ◽  
Lovi Raj Gupta ◽  
Amit Kumar Thakur
Keyword(s):  
Wind Speed ◽  
Solar Radiation ◽  
Real Time ◽  
Time Data ◽  
Wind Speed Prediction ◽  
Real Time Data ◽  
Speed Prediction

A New Approach to Elastodynamic Response of Cylindrical Shell Based on Generalized Solution Structure Theorem for Wave Equation

2010 ◽  
Author(s):  
Shugen Xu ◽  
Weiqiang Wang ◽  
Yan Liu
Keyword(s):  
Wave Equation ◽  
Solution Structure ◽  
Structure Theorem ◽  
Dynamic Pressure ◽  
Structural Response ◽  
Generalized Solution ◽  
New Approach ◽  
Response Data ◽  
Elastodynamic Response ◽  
Detailed Derivation

In this paper, a generalized solution structure theorem has been provided. It can be use to solve the wave equation about the structural response of cylinder under the dynamic pressure. This new approach also can be used to solve a batch of partial differential equations with the similar form. A detailed derivation process has been given to show how the solution is obtained. Finally, a practical example is presented, and all the elastodynamic response data at any point during dynamic pressure can be acquired conveniently.

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