scholarly journals A Feasibility Study to Reduce Infrasound Emissions from Existing Wind Turbine Blades Using a Biomimetic Technique

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4923
Author(s):  
Jinlei Lv ◽  
Wenxian Yang ◽  
Haiyang Zhang ◽  
Daxiong Liao ◽  
Zebin Ren ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Human Health ◽  
High Frequency ◽  
Numerical Study ◽  
Experimental Testing ◽  
Turbine Blades ◽  
Experimental Studies ◽  
Frequency Noise ◽  
Wind Turbine Blades ◽  
High Frequency Noise

Infrasound, i.e., low-frequency noise in the frequency range of 10–200 Hz, produced by rotating wind turbine blades has become a matter of concern because it is harmful to human health. Today, with the rapid increase of wind turbine size, this kind of noise is more worrying than ever. Although much effort has been made to design quiet wind turbine blades, today there is still a lack of effective techniques to reduce infrasound emissions from existing blades. To fill this gap in technology, a biomimetic technique that can be readily applied to reduce infrasound emissions of existing wind turbine blades is studied in this paper using both numerical simulation and experimental testing approaches. The numerical study of the technique is based on the analysis of the sound field distribution near the blade, which is derived by performing both aerodynamic and acoustic simulations of the blade. The experimental study of the technique is based on laboratory tests of two scale models of the blade. Both numerical and experimental studies have shown that the shedding vortices behind the blade can be successfully suppressed by semi-cylindrical rings wrapped on the blade. Consequently, both infrasound and the overall sound pressure level of the noise produced by the blade are significantly reduced. Although the rings fail to show good performance in reducing high-frequency noise, it is not a problem for human health because high-frequency noise is weak and moreover it attenuates rapidly as distance increases. The research also showed that the proposed technique can, not only reduce the infrasound produced by the blade, but can also improve the power coefficient of wind turbines.

scholarly journals TOWARDS EMBEDDED RADCOM-SENSORS IN WIND TURBINE BLADES: PRELIMINARY NUMERICAL AND EXPERIMENTAL STUDIES

2020 ◽  
Vol 90 ◽  
pp. 61-67 ◽  
Author(s):  
Jonas Simon ◽  
Jochen Moll ◽  
Viktor Krozer ◽  
Thomas Kurin ◽  
Fabian Lurz ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Experimental Studies ◽  
Wind Turbine Blades

Numerical study of the structural static and fatigue strength of wind turbine blades

2019 ◽  
Vol 13 ◽  
pp. 1215-1223 ◽  
Author(s):  
M. Tarfaoui ◽  
M. Nachtane ◽  
O.R. Shah ◽  
H. Boudounit
Keyword(s):  
Fatigue Strength ◽  
Wind Turbine ◽  
Numerical Study ◽  
Turbine Blades ◽  
Wind Turbine Blades

High-frequency signals from air-gun arrays

Geophysics ◽  
2011 ◽  
Vol 76 (4) ◽  
pp. Q19-Q27 ◽  
Author(s):  
M. Landrø ◽  
L. Amundsen ◽  
D. Barker
Keyword(s):  
High Frequency ◽  
Experimental Testing ◽  
Seismic Sources ◽  
Frequency Noise ◽  
Suggested Model ◽  
Frequency Effects ◽  
High Frequency Noise ◽  
Air Gun ◽  
Marine Seismic ◽  
High Frequency Effects

We suggest two different mechanisms for generation of high-frequency signals from seismic sources: one type that we interpret as being caused by high-frequency effects close to and within each individual air gun and another type caused by an effect that we refer to as ghost cavitation. The former one is found to have a steep decreasing amplitude trend with frequency, while the latter has a close to 1/f attenuation for frequencies above 1 kHz. A thorough understanding of the effects is of significant importance to quantify and estimate any environmental impact of marine seismic air-gun arrays. The proposed ghost-cavitation mechanism needs further experimental testing. However, given that the suggested model is proven, we think it is possible to attenuate the high-frequency noise generated by compact air-gun arrays by increasing the areal extent of the gun array.

scholarly journals Water Droplet Erosion of Wind Turbine Blades: Mechanics, Testing, Modeling and Future Perspectives

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 157 ◽  
Author(s):  
Mohamed Elhadi Ibrahim ◽  
Mamoun Medraj
Keyword(s):  
Wind Turbine ◽  
Water Droplet ◽  
Prediction Models ◽  
Experimental Testing ◽  
Turbine Blades ◽  
Leading Edge ◽  
Droplet Impact ◽  
Wind Turbine Blades ◽  
Water Droplet Erosion ◽  
Erosion Prediction

The problem of erosion due to water droplet impact has been a major concern for several industries for a very long time and it keeps reinventing itself wherever a component rotates or moves at high speed in a hydrometer environment. Recently, and as larger wind turbine blades are used, erosion of the leading edge due to rain droplets impact has become a serious issue. Leading-edge erosion causes a significant loss in aerodynamics efficiency of turbine blades leading to a considerable reduction in annual energy production. This paper reviews the topic of water droplet impact erosion as it emerges in wind turbine blades. A brief background on water droplet erosion and its industrial applications is first presented. Leading-edge erosion of wind turbine is briefly described in terms of materials involved and erosion conditions encountered in the blade. Emphases are then placed on the status quo of understanding the mechanics of water droplet erosion, experimental testing, and erosion prediction models. The main conclusions of this review are as follow. So far, experimental testing efforts have led to establishing a useful but incomplete understanding of the water droplet erosion phenomenon, the effect of different erosion parameters, and a general ranking of materials based on their ability to resist erosion. Techniques for experimentally measuring an objective erosion resistance (or erosion strength) of materials have, however, not yet been developed. In terms of modelling, speculations about the physical processes underlying water droplet erosion and consequently treating the problem from first principles have never reached a state of maturity. Efforts have, therefore, focused on formulating erosion prediction equations depending on a statistical analysis of large erosion tests data and often with a combination of presumed erosion mechanisms such as fatigue. Such prediction models have not reached the stage of generalization. Experimental testing and erosion prediction efforts need to be improved such that a coherent water droplet erosion theory can be established. The need for standardized testing and data representation practices as well as correlations between test data and real in-service erosion also remains urgent.

scholarly journals Numerical study of a concept for major repair and replacement of offshore wind turbine blades

Wind Energy ◽  
2020 ◽  
Vol 23 (8) ◽  
pp. 1673-1692
Author(s):  
Wilson Guachamin‐Acero ◽  
Zhiyu Jiang ◽  
Lin Li
Keyword(s):  
Wind Turbine ◽  
Numerical Study ◽  
Turbine Blades ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Wind Turbine Blades ◽  
Major Repair

Wind Tunnel Measurements of Convective Heat Transfer With Droplet Impact on a Wind Turbine NACA63-421 Blade

2007 ◽  
Author(s):  
Xin Wang ◽  
Greg Naterer ◽  
Eric Bibeau
Keyword(s):  
Heat Transfer ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Experimental Studies ◽  
Cold Weather ◽  
Wind Turbine Blades ◽  
Airfoil Surface ◽  
Turbine Efficiency ◽  
Innovative Methods ◽  
Important Characterization

Icing of wind turbine blades and sensors in cold climates can cause a significant decrease in turbine efficiency and power production, due to the altered blade aerodynamics and forced shutdowns. Various studies have developed innovative methods for de-icing of wind turbine blades and sensors. In this paper, experimental studies of heat transfer with water droplets on a NACA 63–421 airfoil are studied to simulate anti-icing conditions. Various liquid water contents (LWC) are investigated. The measurements can provide important characterization of heat convection between the airfoil surface and cold surrounding air just before icing accumulation. These experimental measurements can be used to develop better methods to reduce impact of wind turbine icing in cold weather climates. This study is intended to provide useful data to improve methods of anti-icing of wind turbines.

Investigation of Discrete Out-of-Plane Waviness in Composite Wind Turbine Blades Using Ultrasonic Nondestructive Evaluation

2011 ◽  
Author(s):  
Sunil Kishore Chakrapani ◽  
Vinay Dayal ◽  
Daniel Barnard ◽  
David Hsu
Keyword(s):  
Aspect Ratio ◽  
Nondestructive Evaluation ◽  
Wind Turbine ◽  
High Frequency ◽  
Turbine Blades ◽  
Element Model ◽  
Wind Turbine Blades ◽  
Out Of Plane ◽  
Process Detection ◽  
Air Coupled Ultrasonics

With the need for larger and more efficient wind turbine blades, thicker composite sections are manufactured and waviness becomes difficult to control. Thus, there is a need for more effective and field implementable NDE. In this paper we propose a method of detection and quantification of waviness in composite wind turbine blades using ultrasonics. By employing air coupled ultrasonics to facilitate faster and easier scans, we formulated a two step process. Detection was performed with single sided air coupled ultrasonics, and characterization was performed with the help of high frequency contact probes. Severity of the wave was defined with the help of aspect ratio, and several samples with different aspect ratio waves were made. A finite element model for wave propagation in wavy composites was developed, and compared with the experimental results.

Optimization Design of Airfoil Propellers of Modified NACA 4415 Using Computational Fluids Dynamics

2013 ◽  
Vol 789 ◽  
pp. 403-407
Author(s):  
Sudarsono ◽  
Purwanto ◽  
Johny Wahyuadi
Keyword(s):  
Reynolds Number ◽  
Wind Energy ◽  
Wind Turbine ◽  
Optimization Design ◽  
Numerical Study ◽  
Turbine Blades ◽  
Energy Prices ◽  
Wind Turbine Blades ◽  
Pricing Policy ◽  
Computational Fluids Dynamics

Utilization of wind power in Indonesia is less attractive compared with utilization of conventional fuel. This is because the price of wind energy is not competitive when compared with fossil energy prices, and as a result of the implementation of energy pricing policy through subsidies. Before designing the Wind Energy Conversion System, simulation of computational fluid dynamics needs to be done in order for reducing designing time and cost. In this research, modeling and simulation work has been done to figure out the optimum aerodynamics coefficient of wind turbine blades at different Reynolds number. This blade is a modification of standard airfoil of NACA 4415. The aerodynamics coefficient of modify and standard airfoil is then compared. FLUENT software and Spalart-Allmaras Turbulent Model are used in this work. Based on the comparison of the coefficient of aerodynamic, modification NACA 4415 airfoil has better performance at Reynolds number of 4.1 x 104 to 2.5 x 105. The experiment results also showed that based on a numerical study of the modification NACA 4415 airfoil can be used as a basis for the establishment of wind turbine blades.

A NUMERICAL STUDY INTO THE USE OF AUXECTIC STRUCTURES FOR STRUCTURAL DAMPING IN COMPOSITE SANDWICH CORE PANELS FOR WIND TURBINE BLADES

2021 ◽  
pp. 1-18
Author(s):  
Seher Ahsan Khalid ◽  
Abdul Munem Khan ◽  
Owaisur Rahman Shah
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Numerical Study ◽  
Mechanical Energy ◽  
Renewable Energy Sources ◽  
Turbine Blades ◽  
Research Work ◽  
Honeycomb Core ◽  
Wind Turbine Blades ◽  
Half Power

Abstract The ever-increasing demand for energy necessitates the use of renewable energy sources such as wind energy. Wind turbines are widely used to convert wind energy into electrical and mechanical energy, with designs constantly being improved to increase efficiency and power. The turbine blades are considered as long cantilever structures, which are susceptible to vibrations that reduce the performance of the turbine. Honeycomb and closed cell foam sandwich structures have been previously used for turbine blade planking. In this research work, the use of an auxetic core instead of a honeycomb core is proposed for use in wind turbine blades to reduce structural vibrations. Different auxetic topologies are investigated and compared with the half-power method, and their vibration and damping behavior is analyzed in comparison with the conventional honeycomb core. It has been shown through FEA simulations that both the damping ratios are higher and the vibration amplitudes are lower for the auxeticc as compared to conventional closed celled structures like honeycombs.

A Numerical Study of Wind Turbine Airfoil Combined Oscillations Considering Phase Difference under Yaw Loads

2020 ◽  
Author(s):  
Yufeng Yin ◽  
Zhengjie Ji ◽  
Jin Zhang ◽  
Xuan Yin ◽  
Yijie Feng ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Phase Difference ◽  
Numerical Study ◽  
Turbine Blades ◽  
Aerodynamic Performance ◽  
Operating Efficiency ◽  
Wind Turbine Blades ◽  
Pitching Motion ◽  
Blade Section ◽  
Wind Turbine Airfoil

Abstract In order to further improve the operating efficiency of wind turbines and explore the aerodynamic performance of the complex motion of wind turbine blades under yaw loads. In this study, the change in the angle of attack of the blade section airfoil under yaw load can be modeled as an oscillating airfoil and combined with the blade's flapwise motion. The NREL S809 airfoil are chosen for the research, based on the SST k-ω turbulence model with transition correction, under the condition of Reynolds number of 10 6 . The effect of phase difference on its aerodynamic performance under combined flapwise and pitching motion in various flapwise amplitudes and working conditions were analyzed. For the combined oscillations, the effects of the flapwise amplitude ( h ) in the range of 0.2≤ h ≤0.5 are investigated with the phase differences of Φ=±3π/4, ±π/2, ±π/4, 0. The results show that the phase difference between the pitching motion and the flapping motion and the different flapping amplitudes can have a large impact on the aerodynamic performance of the airfoil during dynamic stall, but the degree of influence is greatly different in different situations.

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