scholarly journals Lidar measurement of wind velocity turbulence spectra encountered by a rotating turbine blade

1982 ◽  
Author(s):  
R.M. Hardesty ◽  
J.A. Korrell ◽  
F.F. Jr. Hall
Keyword(s):  
Wind Velocity ◽  
Turbine Blade ◽  
Lidar Measurement ◽  
Turbulence Spectra ◽  
Velocity Turbulence

Wind Turbine Aerodynamic Braking System Analysis Using Chord Wise Spacing

2015 ◽  
Vol 787 ◽  
pp. 217-221 ◽  
Author(s):  
B. Navin Kumar ◽  
K.M. Parammasivam
Keyword(s):  
Renewable Energy ◽  
Wind Turbine ◽  
Wind Velocity ◽  
Turbine Blade ◽  
Wind Turbines ◽  
Renewable Energy Sources ◽  
Energy Resource ◽  
Braking System ◽  
Extreme Wind ◽  
Wind Potential

Wind energy is one of the most significant renewable energy sources in the world. It is the only promising renewable energy resource that only can satisfy the nation’s energy requirements over the growing demand for electricity. Wind turbines have been installed all over the wind potential areas to generate electricity. The wind turbines are designed to operate at a rated wind velocity. When the wind turbines are exposed to extreme wind velocities such as storm or hurricane, the wind turbine rotates at a higher speed that affects the structural stability of the entire system and may topple the system. Mechanical braking systems and Aerodynamic braking systems have been currently used to control the over speeding of the wind turbine at extreme wind velocity. As a novel approach, it is attempted to control the over speeding of the wind turbine by aerodynamic braking system by providing the chord wise spacing (opening). The turbine blade with chord wise spacing alters the pressure distribution over the turbine blade that brings down the rotational speed of the wind turbine within the allowable limit. In this approach, the over speeding of the wind turbine blades are effectively controlled without affecting the power production. In this paper the different parameters of the chord wise spacing such as position of the spacing, shape of the spacing, width of the spacing and impact on power generation are analyzed and the spacing parameters are experimentally optimized.

Lidar Measurement of Wind Velocity Profiles in the Boundary Layer

1980 ◽  
Vol 19 (5) ◽  
pp. 598-605 ◽  
Author(s):  
Jeffery T. Sroga ◽  
Edwin W. Eloranta ◽  
Ted Barber
Keyword(s):  
Boundary Layer ◽  
Wind Velocity ◽  
Velocity Profiles ◽  
Lidar Measurement

scholarly journals Cross-contamination effect on turbulence spectra from Doppler beam swinging wind lidar

2020 ◽  
Vol 5 (2) ◽  
pp. 519-541 ◽  
Author(s):  
Felix Kelberlau ◽  
Jakob Mann
Keyword(s):  
Wind Velocity ◽  
Time Lag ◽  
Turbulence Models ◽  
Horizontal Wind ◽  
Cross Contamination ◽  
Turbulence Spectra ◽  
Contamination Effect ◽  
Turbulence Velocity ◽  
Wind Lidar ◽  
Velocity Spectra

Abstract. Turbulence velocity spectra are of high importance for the estimation of loads on wind turbines and other built structures, as well as for fitting measured turbulence values to turbulence models. Spectra generated from reconstructed wind vectors of Doppler beam swinging (DBS) wind lidars differ from spectra based on one-point measurements. Profiling wind lidars have several characteristics that cause these deviations, namely cross-contamination between the three velocity components, averaging along the lines of sight and the limited sampling frequency. This study focuses on analyzing the cross-contamination effect. We sample wind data in a computer-generated turbulence box to predict lidar-derived turbulence spectra for three wind directions and four measurement heights. The data are then processed with the conventional method and with the method of squeezing that reduces the longitudinal separation distances between the measurement locations of the different lidar beams by introducing a time lag into the data processing. The results are analyzed and compared to turbulence velocity spectra from field measurements with a Windcube V2 wind lidar and ultrasonic anemometers as reference. We successfully predict lidar-derived spectra for all test cases and found that their shape is dependent on the angle between the wind direction and the lidar beams. With conventional processing, cross-contamination affects all spectra of the horizontal wind velocity components. The method of squeezing improves the spectra to an acceptable level only for the case of the longitudinal wind velocity component and when the wind blows parallel to one of the lines of sight. The analysis of the simulated spectra described here improves our understanding of the limitations of turbulence measurements with DBS profiling wind lidar.

scholarly journals All-fiber laser source at 1645  nm for lidar measurement of methane concentration and wind velocity

2020 ◽  
Vol 46 (1) ◽  
pp. 126
Author(s):  
Philippe Benoit ◽  
Simon Le Méhauté ◽  
Julien Le Gouët ◽  
Guillaume Canat
Keyword(s):  
Fiber Laser ◽  
Wind Velocity ◽  
Methane Concentration ◽  
Laser Source ◽  
Lidar Measurement

scholarly journals Study of performance of h-rotor darrieus wind turbines

2021 ◽  
Author(s):  
Sandeep Christy R ◽  
◽  
Kousik S C ◽  
Vishal Subramaniam R ◽  
Santhosh Ram R ◽  
...  
Keyword(s):  
Wind Velocity ◽  
Turbine Blade ◽  
Wind Turbines ◽  
Pitch Angle ◽  
Vertical Axis ◽  
Blade Profile ◽  
Rotor Design ◽  
Wind Velocities ◽  
Major Factors ◽  
Blade Pitch Angle

Vertical Axis Wind Turbines (VAWTs) are mostly manufactured keeping in mind the site and conditions that the wind turbine would face. There is a need to know which type of VAWT would be optimal in the conditions present at the installation site. The major factors involved are blade profile, wind velocity and blade pitch angle. This study is undertaken to study these factors and their effects on influencing the efficiency of the VAWT. A model has been made of a Darrieus VAWT with H-rotor design and is analyzed using CFD. An Iso-surface mesh is made on the model with a cylindrical air-filled domain and a κ-ε turbulence model is applied to study the effects of the wind-and-turbine blade interaction. The domain inlet indicates wind velocity; outlet is set to zero atmospheric gauge pressure and the pressure distribution across the turbine blade wall is measured. The top bottom walls of the domain are not part of the interaction. The study shows that the NACA0012 blade profile fares better than the other profiles across the range of wind velocities. However, it is less efficient with an increase in blade pitch angle for the same value of velocity. NACA0015 blade profile gives good performance when it has a zero pitch angle for intermediate and high wind velocities.

scholarly journals Cross-contamination effect on turbulence spectra from Doppler beam swinging wind lidar

2019 ◽  
Author(s):  
Felix Kelberlau ◽  
Jakob Mann
Keyword(s):  
Wind Velocity ◽  
Turbulence Models ◽  
Field Measurements ◽  
Horizontal Wind ◽  
Cross Contamination ◽  
Turbulence Spectra ◽  
Contamination Effect ◽  
Turbulence Velocity ◽  
Wind Lidar ◽  
Velocity Spectra

Abstract. Turbulence velocity spectra are of high importance for the estimation of loads on wind turbines and other built structures, as well as for fitting measured turbulence values to turbulence models. Doppler beam swinging (DBS) wind lidars generate spectra that differ from spectra based on one-point measurements. Profiling wind lidars have several characteristics that cause these deviations, namely cross-contamination between the three velocity components, averaging along the lines-of-sight, and the limited sampling frequency. This study focuses on analyzing the cross-contamination effect. We sample wind data in a computer generated turbulence box to predict lidar derived turbulence spectra for three wind directions and four measurement heights. The data are then processed with the conventional method and with the method of squeezing. The results are analyzed and compared to turbulence velocity spectra from field measurements with a Windcube V2 wind lidar and ultrasonic anemometers as reference. We successfully predict lidar derived spectra for all test cases and found that their shape is dependent on the angle between the wind direction and the lidar beams. With conventional processing, cross-contamination affects all spectra of the horizontal wind velocity components. The method of squeezing improves the spectra to an acceptable level only for the case of the longitudinal wind velocity component and when the wind blows parallel to one of the lines-of-sight. The analysis of the simulated spectra described here improves our understanding of the limitations of turbulence measurements with DBS profiling wind lidar.

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