A Note on the Decomposition of Aerodynamic Forces Induced by A Wind Turbine Flaps

2020 ◽  
Vol 36 (5) ◽  
pp. 585-593
Author(s):  
Y. Y. Niu ◽  
P. J. Shih ◽  
S. C. Kong
Keyword(s):  
Wind Turbine ◽  
Aerodynamic Force ◽  
Rotational Velocity ◽  
Angular Acceleration ◽  
Surface Friction ◽  
Vertical Axis ◽  
Vertical Axis Wind Turbine ◽  
Gurney Flap ◽  
Force Element ◽  
Element Theory

ABSTRACTIn this study, the aerodynamic characteristics of a vertical-axis wind turbine blade coupled with a high-lift device, such as the Gurney flap at the trailing edge, are investigated. For numerical analysis, the force element theory is used to understand how the Gurney flap influences the force evolution of the lift-type vertical-axis wind turbine. This study shows that the lift and drag can be respectively approximated into four elements, which are induced by volume vorticity, rotational velocity, angular acceleration and surface friction of the flow around the blades. Based on the perspective of the force element theory, the present simulation provides a clear picture of how the Gurney flap influences the formation of the aerodynamic force elements during a rotational cycle for a vertical-axis wind turbine. Simulation results show that the contributions mainly result from the surface vorticities, the rotational acceleration of the airfoil, and the acceleration of the surface.

scholarly journals Design of Vertical Axis Wind Turbine Darrieus Type (H- Darrieus Rotor) of 0.20 KW from the Software Topsolid

2020 ◽  
pp. 52-70
Author(s):  
Hagninou E. V. Donnou ◽  
Drissa Boro ◽  
Donald Abode ◽  
Brunel Capo-Chichi ◽  
Aristide B. Akpo
Keyword(s):  
Wind Turbine ◽  
Permanent Magnets ◽  
Aerodynamic Force ◽  
Low Cost ◽  
Coastal Region ◽  
Vertical Axis ◽  
Digital Design ◽  
Three Dimensions ◽  
Geometrical Shape ◽  
Vertical Axis Wind Turbine

The design of a vertical axis wind turbine (Darrieus type) adapted to the site of Cotonou in the coastal region of Benin was investigated. The statistical study of winds based on the Weibull distribution was carried out on hourly wind data measured at 10 m above the ground by the Agency for the Safety of Air Navigation in Africa and Madagascar (ASECNA) over the period from January 1981 to December 2014. The geometrical and functional parameters of the wind turbine were determined from different models and aerodynamic approaches. The digital design and assembly of the wind turbine components were carried out using the TOPSOLID software. The designed wind turbine has a power of 200W. It is equipped with a synchronous generator with permanent magnets and has three wooden blades with NACA 0015 profile. The optimal coefficient of lift and drag were estimated respectively at 0.7832 and 0.01578. The blades are characterized by an optimum angle of attack estimated at 6.25° with a maximum fineness of 49.63. Their length is 4 m and the maximum thickness is estimated at 0.03 m with a chord of 0.20 m. The volume and mass are respectively equal to 0.024 m3 and 36 kg. The aerodynamic stall occurs at an attack angle of 14.25°. The aerodynamic force exerted on these blades is estimated to be 240 N. The aerodynamic stresses exerted on the rotor are estimated at 15 864 504 Pa and the solidity at 0.27. The efficiency of the wind turbine is 0.323. From TOPSOLID, the geometrical shape of each component of the wind turbine is represented in three dimensions. The assembly allowed to visualizing the wind turbine after export via its graphical interface. The quantity of annual energy produced by the wind turbine was estimated at 0.85 MWh. This study is the first to be carried out in the study area and could reduce the technological dependence of vertical axis wind turbines and their import for low cost energy production.

Performance Improvements for a Vertical Axis Wind Turbine by Means of Gurney Flap

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Yan Yan ◽  
Eldad Avital ◽  
John Williams ◽  
Jiahuan Cui
Keyword(s):  
Wind Turbine ◽  
Stokes Equations ◽  
Numerical Study ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Navier Stokes ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Performance Improvements ◽  
Gurney Flap

Abstract A numerical study was carried out to investigate the effects of a Gurney flap (GF) on the aerodynamics performance of the NACA 00 aerofoil and an associated three-blade rotor of a H-type Darrieus wind turbine. The flow fields around a single aerofoil and the vertical axis wind turbine (VAWT) rotor are studied using unsteady Reynolds-averaged Navier–Stokes equations (URANS). The height of GF ranges from 1% to 5% of the aerofoil chord length. The results show that the GF can increase the lift and lift-to-drag ratio of the aerofoil as associated with the generation of additional vortices near the aerofoil trailing edge. As a result, adding a GF can significantly improve the power coefficient of the VAWT at low tip speed ratio (TSR), where it typically gives low power production. The causing mechanism is discussed in detail, pointing to flow separation and dynamic stall delay.

Effect of geometric parameters of Gurney flap on performance enhancement of straight-bladed vertical axis wind turbine

2021 ◽  
Vol 165 ◽  
pp. 464-480
Author(s):  
Haitian Zhu ◽  
Wenxing Hao ◽  
Chun Li ◽  
Shuai Luo ◽  
Qingsong Liu ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Performance Enhancement ◽  
Vertical Axis ◽  
Geometric Parameters ◽  
Vertical Axis Wind Turbine ◽  
Gurney Flap

Vibration Response Behaviour of a High Solidity, Low Rotational Velocity, Vertical Axis Wind Turbine

2010 ◽  
Author(s):  
Kevin W. McLaren ◽  
Stephen W. Tullis ◽  
Samir Ziada
Keyword(s):  
Wind Turbine ◽  
Natural Frequencies ◽  
Rotational Velocity ◽  
Vertical Axis ◽  
Vibration Response ◽  
Resonance Excitation ◽  
Test Cases ◽  
Vertical Axis Wind Turbine ◽  
Aerodynamic Loading ◽  
End Conditions

A series of full scale experimental wind tunnel tests were performed to determine the aerodynamic loading behaviour on the airfoils of a high solidity, low rotational velocity, 3 bladed H-type vertical axis wind turbine. The primary vibration response was resonance excitation of the dominant whirling mode of the turbine. However, for a significant number of test cases, resonance behaviour was also observed in the bending strains of the airfoil support struts, primarily corresponding to higher natural frequencies. Furthermore, under various test conditions, vibration amplitude within the support struts was observed to change dramatically during a single test run, suggesting that the vibration was jumping between sets of airfoil support struts in a complex beating mode. In order to isolate the numerous vibration excitation and response behaviours, tests were performed over a range of flow velocities from 8 m/s to 11 m/s with two different support shaft end conditions.

A Straight-Bladed Vertical Axis Wind Turbine With a Directed Guide Vane: Mechanism of Performance Improvement

2008 ◽  
Author(s):  
Hideki Kuma ◽  
Manabu Takao ◽  
Toshiyuki Beppu ◽  
Takao Maeda ◽  
Yasunari Kamada ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Performance Improvement ◽  
Aerodynamic Force ◽  
Guide Vane ◽  
Vortex Method ◽  
Vertical Axis ◽  
Rotor Blades ◽  
Power Coefficient ◽  
Vertical Axis Wind Turbine ◽  
Lagrangian Simulation

A straight-bladed vertical axis wind turbine with a directed guide vane has been proposed in order to enhance its torque. The experimental study of the proposed wind turbine was carried out by a wind tunnel with an outlet diameter of 1.8m. The tested rotor has 3 straight rotor blades with a profile of NACA0018, a radius of 0.35 m and a height of 0.7 m. The guide vane which consists of an arc plate rotates around the rotor and is directed to the wind by aerodynamic force generated by tail vanes, so as to put the guide vane in upstream of the rotor. As a result, the performance of the straight-bladed vertical axis turbine was improved by means of the directed guide vane and the power coefficient of the proposed wind turbine was approximately 1.2 times higher than that of the original wind turbine which has no guide vane. Further, flows around the proposed wind turbine have been investigated by use of the vortex method which provides a Lagrangian simulation of unsteady and vortical flows.

A Straight-Bladed Vertical Axis Wind Turbine With a Directed Guide Vane Row

2007 ◽  
Author(s):  
Manabu Takao ◽  
Takao Maeda ◽  
Yasunari Kamada ◽  
Michiaki Oki ◽  
Hideki Kuma
Keyword(s):  
Experimental Study ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Aerodynamic Force ◽  
Guide Vane ◽  
Vertical Axis ◽  
Rotor Blades ◽  
Power Coefficient ◽  
Vertical Axis Wind Turbine ◽  
Vertical Axis Turbine

A straight-bladed vertical axis wind turbine with a directed guide vane row has been proposed in order to enhance its torque. The experimental study of the proposed wind turbine was carried out by a wind tunnel with an outlet diameter of 1.8m. The tested rotor has some straight rotor blades with a profile of NACA0015, a radius diameter of 0.3 m and a height of 0.7 m. The guide vane row having 3 arc plates rotates around the rotor and is directed to the wind by aerodynamic force generated by tail vanes, so as to put the guide vane row in upstream of the rotor. As a result, the performance of the straight-bladed vertical axis turbine was improved by means of the directed guide vane row. Further, by the use of the guide vane row adopted in the study, the power coefficient of the proposed wind turbine was approximately 1.5 times higher than that of the original wind turbine which has no guide vane.

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