scholarly journals Aerodynamic Characteristics of Airfoil and Vertical Axis Wind Turbine Employed with Gurney Flaps

2021 ◽  
Vol 13 (8) ◽  
pp. 4284
Author(s):  
Yosra Chakroun ◽  
Galih Bangga
Keyword(s):  
Wind Turbine ◽  
Numerical Solutions ◽  
Vertical Axis ◽  
Power Production ◽  
Aerodynamic Characteristics ◽  
Maximum Height ◽  
Vertical Axis Wind Turbine ◽  
Time Step ◽  
Gurney Flaps ◽  
Gurney Flap

In the present studies, the effects of Gurney flaps on aerodynamic characteristics of a static airfoil and a rotating vertical axis wind turbine are investigated by means of numerical approaches. First, mesh and time step studies are conducted and the results are validated with experimental data in good agreement. The numerical solutions demonstrate that the usage of Gurney flap increases the airfoil lift coefficient CL with a slight increase in drag coefficient CD. Furthermore, mounting a Gurney flap at the trailing edge of the blade increases the power production of the turbine considerably. Increasing the Gurney flap height further increases the power production. The best performance found is obtained for the maximum height used in this study at 6% relative to the chord. This is in contrast to the static airfoil case, which shows no further improvement for a flap height greater than 0.5%c. Increasing the angle of the flap decreases the power production of the turbine slightly but the load fluctuations could be reduced for the small value of the flap height. The present paper demonstrates that the Gurney flap height for high solidity turbines is allowed to be larger than the classical limit of around 2% for lower solidity turbines.

Effect of trailing edge dual synthesis jets actuator on aerodynamic characteristics of a straight-bladed vertical axis wind turbine

Energy ◽  
2022 ◽  
Vol 238 ◽  
pp. 121792
Author(s):  
Peilin Wang ◽  
Qingsong Liu ◽  
Chun Li ◽  
Weipao Miao ◽  
Shuai Luo ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Aerodynamic Characteristics ◽  
Vertical Axis Wind Turbine ◽  
Trailing Edge

Coupled Dynamics of a Vertical Axis Wind Turbine (VAWT) With Active Blade Pitch Control on a Semi-Submersible Floater

2018 ◽  
Author(s):  
Ebert Vlasveld ◽  
Fons Huijs ◽  
Feike Savenije ◽  
Benoît Paillard
Keyword(s):  
Wind Turbine ◽  
Wind Velocity ◽  
Vertical Axis ◽  
Power Production ◽  
Mooring Line ◽  
Vertical Axis Wind Turbine ◽  
Coupled Dynamics ◽  
Low Frequencies ◽  
Pitch Control ◽  
Thrust And Torque

A vertical axis wind turbine (VAWT) typically has a low position of the center of gravity and a large allowable tilt angle, which could allow for a relatively small floating support structure. Normally however, the drawback of large loads on the VAWT rotor during parked survival conditions limits the extent to which the floater size can be reduced. If active blade pitch control is applied to the VAWT, this drawback can be mitigated and the benefits can be fully utilized. The coupled dynamics of a 6 MW VAWT with active blade pitch control supported by a GustoMSC Tri-Floater semi-submersible floater have been simulated using coupled aero-hydro-servo-elastic software. The applied blade pitch control during power production results in a steady-state thrust curve which is more comparable to a HAWT, with the maximum thrust occurring at rated wind velocity. During power production, floater motions occur predominantly at low frequencies. These low frequency motions are caused by variations in the wind velocity and consequently the rotor thrust and torque. For the parked survival condition, it is illustrated that active blade pitch control can be used to effectively reduce dynamic load variations on the rotor and minimize floater motions and mooring line tensions.

Aerodynamic Analysis for Camber Effect in Vertical Wind Turbine System

2011 ◽  
Author(s):  
Jinwook Kim ◽  
Dohyung Lee ◽  
Junhee Han ◽  
Sangwoo Kim
Keyword(s):  
Numerical Simulation ◽  
Wind Turbine ◽  
Vertical Axis ◽  
Aerodynamic Characteristics ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine ◽  
Low Wind Speed ◽  
Wind Turbine System ◽  
Physical Features ◽  
The Ideal

The Vertical Axis Wind Turbine (VAWT) has advantages over Horizontal Axis Wind Turbine (HAWT) that it allows less chance to be degraded independent of wind direction and turbine can be operated even at the low wind speed. The objective of this study is to analyze aerodynamics of the VAWT airfoil and investigate the ideal shape of airfoil, more specifically cambers. The analysis of aerodynamic characteristics with various cambers has been performed using numerical simulation with CFD software. As the numerical simulation discloses local physical features around wind turbine, aerodynamic performance such as lift, drag and torque are computed for single airfoil rotation and multiple airfoil rotation cases. Through this study more effective airfoil shape is suggested based vortex-airfoil interaction studies.

Computational Analysis of Airfoil Merging and its Effect on Performance of Lift Based Vertical Axis Wind Turbine

2016 ◽  
Author(s):  
Akshay Basavaraj
Keyword(s):  
Reynolds Number ◽  
Wind Turbine ◽  
Lift Coefficient ◽  
Turbine Blades ◽  
Vertical Axis ◽  
Aerodynamic Characteristics ◽  
Vertical Axis Wind Turbine ◽  
Low Wind Speed ◽  
Naca 0012 ◽  
Selection Of

In regions of low wind speed, overcoming the starting torque of a Vertical Axis Wind Turbine (VAWT) becomes a challenge aspect. In order to overcome this adversity, careful selection of airfoils for the turbine blades becomes a priority. This paper tries to address the issue utilizing an approach wherein by observing the effect of merging two airfoils. Two airfoils which are of varying camber and thickness are merged and their aerodynamic characteristics are evaluated using the software XFOIL 6.96. For a variation in angle of attack from 0 to 90°, aerodynamic analysis is done in order to observe the behavior of one quarter of the entire VAWT cycle. An objective function is developed so as to observe the maximum possible torque generated by these airfoils at Reynolds number varying from 15,000–120,000. Due to change in the value of CL observed at Low Reynolds Number using commercial CFD softwares, multiple objective functions are utilized to observe the behavior over a range of Reynolds number. An experimental co-relation between the cut-in velocity and the lift-coefficient of the airfoils is developed in order to predict the cut-in velocity of the interpolated airfoils. The airfoils used for this paper are NACA 0012, NACA 0018, FX 66 S196, Clark Y (smooth), PT 40, SD 7032, A 18, SD 7080, SG 6043 and SG 6040.

Aerodynamic characteristics of Straight-bladed Vertical Axis Wind Turbine with a curved-outline wind gathering device

2020 ◽  
Vol 203 ◽  
pp. 112249 ◽  
Author(s):  
Yan Li ◽  
Shouyang Zhao ◽  
Chunming Qu ◽  
Guoqiang Tong ◽  
Fang Feng ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Aerodynamic Characteristics ◽  
Vertical Axis Wind Turbine

Design and Test of a Vertical-Axis Wind Turbine with Pitch Control

2012 ◽  
Vol 225 ◽  
pp. 338-343 ◽  
Author(s):  
J.J. Miau ◽  
S.Y. Liang ◽  
R.M. Yu ◽  
C.C. Hu ◽  
T.S. Leu ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Aerodynamic Characteristics ◽  
Vertical Axis Wind Turbine ◽  
Variable Pitch ◽  
Pitch Control ◽  
Remarkable Improvement ◽  
The One ◽  
Variable Pitch Control ◽  
Starting Torque

The concept of pitch control has been implemented in the design of a small vertical-axis wind turbine. Benefits gained can be shown by the experimental and numerical results presented in this paper. As found, the method of variable pitch control outperforms the one of fixed pitch control. The present results show that the former can make remarkable improvement on the starting torque as well as the aerodynamic characteristics at low tip speed ratios.

Application of Variable Blade Pitch Control on Improving the Performance of Vertical Axis Wind Turbine

2012 ◽  
Vol 229-231 ◽  
pp. 2339-2342
Author(s):  
J.C. Cheng ◽  
S.J Su ◽  
J.J Miau
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Aerodynamic Characteristics ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Energy Capture ◽  
Pitch Control ◽  
Tip Speed Ratio ◽  
Torque Coefficient ◽  
Variable Pitch Control

A three blades vertical axis wind turbine simulation is performed to study the unsteady aerodynamic characteristics with blade pitch control. Several fixed and variable blade pitch models under different tip speed ratio are adopted to improve performance of the wind turbine. Results show that an appropriate pitch control model can effectively decrease the range of negative torque regime to reduce the vibration of the wind turbine. Besides, the average torque coefficient as well as the energy capture efficiency can be also improved, especially for the lower tip speed ratio. The overall efficiency of the wind turbines in power generation will be enhanced. For the cases under the tip speed ratio between 1 and 3, the efficiency can be enhanced 243% and 486% for fixed and variable pitch control models respectively as comparing with non-pitch control cases.

Momentum Analytical Model of a Circulation Controlled Vertical Axis Wind Turbine

2009 ◽  
Author(s):  
Jay P. Wilhelm ◽  
Chad Panther ◽  
Franz A. Pertl ◽  
James E. Smith
Keyword(s):  
Wind Turbine ◽  
Analytical Model ◽  
Vertical Axis ◽  
Power Production ◽  
Circulation Control ◽  
Vertical Axis Wind Turbine ◽  
Trailing Edge ◽  
Operating Range ◽  
Wind Speeds ◽  
Stream Tubes

A possible method for analytically modeling a CC-VAWT (Circulation Controlled Vertical Axis Wind Turbine) is the momentum model, based upon the conservation of momentum principal. This model can consist of a single or multiple stream tubes and/or upwind and downwind partitions. A large number of stream tubes and the addition of the partition can increase the accuracy of the model predictions. The CC-VAWT blade has blowing slots located on the top and bottom trailing edges and have the capability to be site controlled in multiple sections along the span of the blade. The turbine blade, augmented to include circulation control capabilities, replaces the sharp trailing edge of a standard airfoil with a rounded surface located adjacent to the blowing slots. Circulation control (CC), along with a rounded trailing edge, induces the Coanda effect, entraining the flow field near the blowing slots thus preventing or delaying separation. Ultimately, circulation control adds momentum due to the mass flow of air coming out of the blowing slots, but is negligible compared to the momentum of the free stream air passing through the area of the turbine. In order to design for a broader range of operating speeds that will take advantage of circulation control, an analytical model of a CC-VAWT is helpful. The analytical modeling of a CC-VAWT could provide insight into the range of operational speeds in which circulation control is beneficial. The ultimate goal is to increase the range of operating speeds where the turbine produces power. Improvements to low-speed power production and the elimination or reduction of startup assistance could be possible with these modifications. Vertical axis wind turbines are typically rated at a particular ratio of rotational to wind speed operating range. In reality, however, wind speeds are variant and stray from the operating range causing the power production of a wind turbine to suffer. These turbines, unless designed specifically for low speed operation, may require rotational startup assistance. The added lift due to circulation control at low wind speeds, under certain design conditions, will allow the CC-VAWT to produce more power than a conventional VAWT of the same size. Circulation control methods, such as using blowing slots on the trailing edge are modeled as they are applied to a VAWT blade. A preliminary CC-VAWT was modeled using a standard NACA 0018 airfoil, modified to include blowing slots and a rounded trailing edge. This paper describes an analytical momentum model that can be used to predict the preliminary performance of a CC-VAWT.

scholarly journals A method to analyze power output of vertical-axis wind turbines under rain

2018 ◽  
Vol 56 (6) ◽  
pp. 761
Author(s):  
Duc Huu Nguyen
Keyword(s):  
Wind Turbine ◽  
Power Output ◽  
Vertical Axis ◽  
Power Production ◽  
Vertical Axis Wind Turbine ◽  
Physical Processes ◽  
Vertical Axis Wind Turbines ◽  
Rain Drops ◽  
Weather Changes ◽  
And Performance

A method to analyze effect power output of a vertical axis wind turbine under rain is proposed. The rain had the effect of increasing the drag, slowing the rotational speed of the wind turbine and decreasing the power and performance. More and more ambitious projects for wind turbine production being set on many where on Vietnam, it is necessary to understand all the factors, especially by weather changes, that might affect wind power production. In this research, we lay out a model to estimate the effect of rainfall by simulating the actual physical processes of the rain drops forming on the surface of the blades of a vertical-axis wind turbine (VAWT), thereby determining optimal wetness, then power and performance respectively. This could have an effect on the control strategy necessary for designing and controlling wind turbine.

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