About the impact of wind turbine blade tip vortices on helicopter rotor trim and rotor blade motion

2017 ◽  
Vol 9 (1) ◽  
pp. 67-84 ◽  
Author(s):  
Berend G. van der Wall ◽  
Paul H. Lehmann
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Rotor Blade ◽  
Wind Turbine Blade ◽  
Helicopter Rotor ◽  
Tip Vortices ◽  
Blade Tip ◽  
Rotor Trim ◽  
The Impact

Wind Turbine Blade Coating Fatigue Induced by Raindrop Impact

2020 ◽  
Author(s):  
Weifei Hu ◽  
Weiyi Chen ◽  
Xiaobo Wang ◽  
Zhenyu Liu ◽  
Jianrong Tan ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Crack Growth ◽  
Turbine Blade ◽  
Wind Turbine Blade ◽  
Rain Event ◽  
Rain Intensity ◽  
Texture Model ◽  
The Impact ◽  
Blade Coating ◽  
Raindrop Impact

Abstract With the increase of wind energy production demand, the need to manufacture larger wind turbine blades is on the rise. Because of the high tip speed of the large blade, the blade could be impacted by high-speed objects such as raindrops. This research focuses on developing a computational model for analyzing wind turbine blade coating fatigue induced by raindrop impact. A stochastic rain texture model is used to simulate a realistic rain event determined by a rain intensity and a rain duration. A smoothed particle hydrodynamic approach is implemented to calculate the impact stress considering a single raindrop. A stress interpolation method is proposed to accurately and efficiently estimate the impact of stress under a random rain event. Besides, a crack growth law is used to explain the process of coating shedding. Through a method for calculating crack growth length based on stress, this paper analyzes crack growth life as a function of the rain intensity and the rain duration. This function, together with the statistics of rainfall history, provides a new approach for estimating the expected fatigue life of the blade coating.

Experimental and Numerical Investigation of Inflow Turbulence on the Performance of Wind Turbine Airfoils

2013 ◽  
Author(s):  
O. Eisele ◽  
G. Pechlivanoglou ◽  
C. N. Nayeri ◽  
C. O. Paschereit
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Wind Tunnel Test ◽  
Wind Turbine Blade ◽  
Two Dimensional ◽  
Airfoil Surface ◽  
Wind Tunnel Measurements ◽  
Inflow Turbulence ◽  
The Impact

Wind turbine blade design is currently based on the combination of a plurality of airfoil sections along the rotorblade span. The two-dimensional airfoil characteristics are usually measured with wind tunnel experiments or computed by means of numerical simulation codes. The general airfoil input for the calculation of the rotorblade power characteristics as well as the subsequent aerodynamic and aeroelastic loads are based on these two-dimensional airfoil characteristics. In this paper, the effects of inflow turbulence and wind tunnel test measurement deviations are investigated and discussed, to allow considerations of such effects in the rotorblade design process. The results of CFD simulations with various turbulence models are utilized in combination with wind tunnel measurements in order to assess the impact of such discrepancies. It seems that turbulence, airfoil surface roughness and early transition effects are able to contribute significantly to the uncertainty and scattering of measurements. Various wind tunnel facilities generate different performance characteristic curves, while grid-generated turbulence is generally not included in the wind tunnel measurements during airfoil characterization. Furthermore the correlation of grid-generated wind tunnel turbulence with the atmospheric turbulence time and length scales is not easily achieved. All the aforementioned uncertainties can increase the performance scattering of current wind turbine blade designs as well as the generated aeroelastic loads. A brief assessment of the effect of such uncertainties on wind turbine performance is given at the last part of this work by means of BEM simulations on a wind turbine blade.

Wind Turbine Blade Tip Flow and Noise Prediction by Large-eddy Simulation

2004 ◽  
Vol 126 (4) ◽  
pp. 1017-1024 ◽  
Author(s):  
Oliver Fleig ◽  
Makoto Iida ◽  
Chuichi Arakawa
Keyword(s):  
Large Eddy Simulation ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Acoustic Emissions ◽  
Wind Turbine Blade ◽  
Tip Vortex ◽  
Aerodynamic Noise ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Blade Tip

The purpose of this research is to investigate the physical mechanisms associated with broadband tip vortex noise caused by rotating wind turbines. The flow and acoustic field around a wind turbine blade is simulated using compressible large-eddy simulation and direct noise simulation, with emphasis on the blade tip region. The far field aerodynamic noise is modeled using acoustic analogy. Aerodynamic performance and acoustic emissions are predicted for the actual tip shape and an ogee type tip shape. For the ogee type tip shape the sound pressure level decreases by 5 dB for frequencies above 4 kHz.

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