Relating Turbulence to Wind Turbine Blade Loads: Parametric Study with Multiple Regression Analysis

1999 ◽  
Vol 121 (3) ◽  
pp. 156-161 ◽  
Author(s):  
T. Kashef ◽  
S. R. Winterstein
Keyword(s):  
Regression Analysis ◽  
Wind Turbine ◽  
Parametric Study ◽  
Turbine Blades ◽  
Low Frequency ◽  
Frequency Content ◽  
Wind Turbine Blades ◽  
Systematic Method ◽  
Highly Correlated ◽  
Blade Loads

Different wind parameters are studied to find a set that is most useful in estimating fatigue loads on wind turbine blades. The histograms of rainflow counted stress ranges are summarized through their first three statistical moments and regression analysis is used to estimate these moments in various wind conditions. A systematic method of comparing the ability of different wind parameters to estimate the moments is described and results are shown for flapwise loads on three HAWTs. In the case of two of these turbines, the stress ranges are shown to be highly correlated with a turbulence measure obtained by removing a portion of the low-frequency content of the wind.

Predictions of Structural Testing Characteristics for Wind Turbine Blades

2009 ◽  
Author(s):  
Michael Desmond ◽  
Darris White
Keyword(s):  
Wind Turbine ◽  
Fatigue Testing ◽  
Turbine Blades ◽  
Structural Testing ◽  
Wind Turbine Blades ◽  
Static Testing ◽  
Extreme Load ◽  
Design Loads ◽  
Certification Requirements ◽  
Blade Loads

Static and fatigue structural testing of wind turbine blades provides manufacturers with quantitative details in order to improve designs and meet certification requirements. Static testing entails applying extreme load cases through a combination of winches and weights to determine the ultimate strength of the blade while fatigue testing entails applying the operating design loads through forced hydraulics or resonant excitation systems over the life cycle of the blade to determine durability. Recently, considerable efforts have been put forth to characterize the reactions of wind turbine blades during structural testing in order to develop load and deflection predictions for the next generation of blade test facilities. Incorporating years of testing experience with historical test data from several wind turbine blades, curve fits were developed to extrapolate properties for blades up to one hundred meters in length. Furthermore, conservative assumptions were employed to account for blade variations due to inconsistent manufacturing processes. In short, this paper will outline the predictions of wind turbine blade loads and deflections during static and fatigue structural testing.

Crack detection technique for operating wind turbine blades using Vibro-Acoustic Modulation

2014 ◽  
Vol 13 (6) ◽  
pp. 660-670 ◽  
Author(s):  
Sungmin Kim ◽  
Douglas E Adams ◽  
Hoon Sohn ◽  
Gustavo Rodriguez-Rivera ◽  
Noah Myrent ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Crack Detection ◽  
Turbine Blades ◽  
Low Frequency ◽  
Detection Technique ◽  
New Technique ◽  
Wind Turbine Blades ◽  
Excitation Signal ◽  
Acoustic Modulation

This article presents a new technique for identifying cracks in wind turbine blades undergoing operational loads using the Vibro-Acoustic Modulation technique. Vibro-Acoustic Modulation utilizes a low-frequency pumping excitation signal in conjunction with a high-frequency probing excitation signal to create the modulation that is used to identify cracks. Wind turbines provide the ideal conditions in which Vibro-Acoustic Modulation can be utilized because wind turbines experience large low-frequency structural vibrations during operation which can serve as the low-frequency pumping excitation signal. In this article, the theory for the vibro-acoustic technique is described, and the proposed crack detection technique is demonstrated with Vibro-Acoustic Modulation experiments performed on a small Whisper 100 wind turbine in operation. The experimental results are also compared with two other conventional vibro-acoustic techniques in order to validate the new technique. Finally, a computational study is demonstrated for choosing a proper probing signal with a finite element model of the cracked blade to maximize the sensitivity of the technique for detecting cracks.

Experimental study of particle dampers applied to wind turbine blades to reduce low-frequency sound emission

2021 ◽  
Vol 263 (6) ◽  
pp. 71-82
Author(s):  
Braj Bhushan Prasad ◽  
Fabian Duvigneau ◽  
Daniel Juhre ◽  
Elmar Woschke
Keyword(s):  
Experimental Study ◽  
Granular Material ◽  
Wind Turbine ◽  
Laser Scanning ◽  
Turbine Blades ◽  
Low Frequency ◽  
Small Scale ◽  
Full Potential ◽  
Sound Emission ◽  
Wind Turbine Blades

Sound emission from an onshore wind turbine is one of the significant hurdles to use wind energy to its full potential. The vibration caused by the generator is transmitted to the blades, which radiates the sound to the surrounding. The purpose of this experimental study is to present a passive vibration reduction concept, which is based on the high damping properties of granular materials. The efficiency of this concept will be investigated using a laser scanning vibrometer device. For the experimental purpose in the laboratory, small-scale replicas inspired by the original configurations are used as reference geometries for the wind turbine generator and the blades. Vibrations of the prototype, with and without granular material filling, will be determined and compared with each other. The influence of the amount of granular material inside the structure is also investigated. Apart from this, different types of granular filling are examined with respect to their efficiency in reducing the amplitude of vibration of the structure while being as light as possible in order to design a lightweight solution, which increases the overall mass of the wind turbine marginally.

A Study on Coupled Bending and Torsional Vibrations of Wind Turbine Blades

2012 ◽  
Vol 622-623 ◽  
pp. 1236-1242 ◽  
Author(s):  
Mary V. Bastawrous ◽  
Ayman A. El-Badawy
Keyword(s):  
Wind Turbine ◽  
Parametric Study ◽  
Turbine Blades ◽  
Vibration Modes ◽  
Blade Design ◽  
Wind Turbine Blades ◽  
Analysis Techniques ◽  
Material Stiffness ◽  
Dimensional Parameters ◽  
Collective Influence

A parametric study is developed to investigate the effect of geometry, material stiffness and the rotational motion on the coupled flapwise bending and torsional vibration modes of a wind turbine blade. The assumed modes method is used to discretize the derived kinetic and potential energy terms. Lagrange’s equations are used to derive the modal equations from the discretized terms, which are solved for the vibration frequencies. The parametric study utilizes dimensional analysis techniques to study the collective influence of the investigated parameters by combining them into few non-dimensional parameters, thus providing deeper insight to the physics of the dynamic response. Results would be useful in providing rules and guidelines to be used in blade design.

A parametric study of coupled-mode flutter for MW-size wind turbine blades

Wind Energy ◽  
2015 ◽  
Vol 19 (3) ◽  
pp. 497-514 ◽  
Author(s):  
Pariya Pourazarm ◽  
Yahya Modarres-Sadeghi ◽  
Matthew Lackner
Keyword(s):  
Wind Turbine ◽  
Parametric Study ◽  
Turbine Blades ◽  
Wind Turbine Blades ◽  
Coupled Mode

scholarly journals Minimum Leading Edge Protection Application Length to Combat Rain-Induced Erosion of Wind Turbine Blades

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1629
Author(s):  
Amrit Shankar Verma ◽  
Sandro Di Noi ◽  
Zhengru Ren ◽  
Zhiyu Jiang ◽  
Julie J. E. Teuwen
Keyword(s):  
Wind Turbine ◽  
Parametric Study ◽  
Turbine Blades ◽  
Leading Edge ◽  
Spanwise Direction ◽  
Probabilistic Framework ◽  
Wind Turbine Blades ◽  
Rule Of Thumb ◽  
Higher Power

Leading edge erosion (LEE) repairs of wind turbine blades (WTBs) involve infield application of leading edge protection (LEP) solutions. The industry is currently aiming to use factory based LEP coatings that can applied to the WTBs before they are shipped out for installation. However, one of the main challenges related to these solutions is the choice of a minimum LEP application length to be applied in the spanwise direction of the WTBs. Generally, coating suppliers apply 10–20 m of LEP onto the blades starting from the tip of the blade using the “rule of thumb”, and no studies in the literature exist that stipulate how these LEP lengths can be calculated. In this study, we extend the scope of a recently developed long-term probabilistic framework to determine the minimum LEP application length required for WTBs to combat rain-induced erosion. A parametric study is performed where different wind turbines with varying power ratings of 2.1 MW to 15 MW at different Dutch sites ranging from inland to coastal are considered. The results of the study show that the LEP application length is sensitive to the choice of the site, as well as the turbine attributes. Further, LEP lengths for WTBs are found to be the highest for turbines installed at coastal sites and turbines with higher power ratings. A detailed investigation is further performed to check the sensitivity of the LEP application length with the wind turbine parameters. The results of the study are expected to provide guidelines to the industry for efficient repair strategies for WTBs.

scholarly journals Reducing infrasound and low frequency noise from wind turbine blades and rotors using ANC

2015 ◽  
Vol 3 (1) ◽  
pp. 3 ◽  
Author(s):  
Gloria Adewumi ◽  
Lumbumba Taty-Etienne Nyamayoka ◽  
Freddie Inambao
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Wind Turbine Blades
Sign in / Sign up

Export Citation Format

Share Document