Correction: Effect of trailing edge serration on the lift and drag characteristics of NACA0012 airfoil wing

2017 ◽  
Author(s):  
Usama Hussain ◽  
Saif U. Malook ◽  
Burhan Shabir ◽  
Ozaif Ali ◽  
Sarvat M. Ahmad
Keyword(s):  
Trailing Edge ◽  
Naca0012 Airfoil ◽  
Correction Effect ◽  
Lift And Drag

scholarly journals A Parametric Study of Trailing Edge Flap Implementation on Three Different Airfoils Through an Artificial Neuronal Network

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 828
Author(s):  
Igor Rodriguez-Eguia ◽  
Iñigo Errasti ◽  
Unai Fernandez-Gamiz ◽  
Jesús María Blanco ◽  
Ekaitz Zulueta ◽  
...  
Keyword(s):  
Aerodynamic Coefficients ◽  
Trailing Edge ◽  
High Lift ◽  
Trailing Edge Flaps ◽  
Artificial Neural Network Ann ◽  
Lift And Drag ◽  
Artificial Neuronal Network ◽  
Naca 0012 ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Trailing edge flaps (TEFs) are high-lift devices that generate changes in the lift and drag coefficients of an airfoil. A large number of 2D simulations are performed in this study, in order to measure these changes in aerodynamic coefficients and to analyze them for a given Reynolds number. Three different airfoils, namely NACA 0012, NACA 64(3)-618, and S810, are studied in relation to three combinations of the following parameters: angle of attack, flap angle (deflection), and flaplength. Results are in concordance with the aerodynamic results expected when studying a TEF on an airfoil, showing the effect exerted by the three parameters on both aerodynamic coefficients lift and drag. Depending on whether the airfoil flap is deployed on either the pressure zone or the suction zone, the lift-to-drag ratio, CL/CD, will increase or decrease, respectively. Besides, the use of a larger flap length will increase the higher values and decrease the lower values of the CL/CD ratio. In addition, an artificial neural network (ANN) based prediction model for aerodynamic forces was built through the results obtained from the research.

The Effect of Airfoil Shape on Trailing Edge Noise

2019 ◽  
Vol 27 (02) ◽  
pp. 1850020 ◽  
Author(s):  
Seongkyu Lee
Keyword(s):  
Boundary Layer ◽  
Noise Source ◽  
Source Region ◽  
Low Frequency ◽  
Suction Side ◽  
Frequency Noise ◽  
Pressure Side ◽  
Trailing Edge ◽  
Trailing Edge Noise ◽  
Naca0012 Airfoil

This paper investigates the effect of airfoil shape on trailing edge noise. The boundary layer profiles are obtained by XFOIL and the trailing edge noise is predicted by a TNO semi-empirical model. In order to investigate the noise source characteristics, the wall pressure spectrum is decomposed into three components. This decomposition helps in finding the dominant source region and the peak noise frequency for each airfoil. The method is validated for a NACA0012 airfoil, and then five additional wind turbine airfoils are examined: NACA0018, DU96-w-180, S809, S822 and S831. It is found that the dominant source region is around 40% of the boundary layer thickness for both the suction and pressure sides for a NACA0012 airfoil. As airfoil thickness and camber increase, the maximum source region moves slightly upward on the suction side. However, the effect of the airfoil shape on the maximum source region on the pressure side is negligible, except for the S831 airfoil, which exhibits an extension of the noise source region near the wall at high frequencies. As airfoil thickness and camber increase, low frequency noise is increased. However, a higher camber reduces low frequency noise on the pressure side. The maximum camber position is also found to be important and its rear position increases noise levels on the suction side.

scholarly journals Prediction of Airfoil Stall Based on a Modified k−v2¯−ω Turbulence Model

Mathematics ◽  
2022 ◽  
Vol 10 (2) ◽  
pp. 272
Author(s):  
Chenyu Wu ◽  
Haoran Li ◽  
Yufei Zhang ◽  
Haixin Chen
Keyword(s):  
Experimental Data ◽  
Shear Layer ◽  
Turbulence Model ◽  
Turbulence Models ◽  
Reynolds Numbers ◽  
Navier Stokes ◽  
Trailing Edge ◽  
Naca0012 Airfoil ◽  
Separated Shear Layer ◽  
Non Equilibrium

The accuracy of an airfoil stall prediction heavily depends on the computation of the separated shear layer. Capturing the strong non-equilibrium turbulence in the shear layer is crucial for the accuracy of a stall prediction. In this paper, different Reynolds-averaged Navier–Stokes turbulence models are adopted and compared for airfoil stall prediction. The results show that the separated shear layer fixed k−v2¯−ω (abbreviated as SPF k−v2¯−ω) turbulence model captures the non-equilibrium turbulence in the separated shear layer well and gives satisfactory predictions of both thin-airfoil stall and trailing-edge stall. At small Reynolds numbers (Re~105), the relative error between the predicted CL,max of NACA64A010 by the SPF k−v2¯−ω model and the experimental data is less than 3.5%. At high Reynolds numbers (Re~106), the CL,max of NACA64A010 and NACA64A006 predicted by the SPF k−v2¯−ω model also has an error of less than 5.5% relative to the experimental data. The stall of the NACA0012 airfoil, which features trailing-edge stall, is also computed by the SPF k−v2¯−ω model. The SPF k−v2¯−ω model is also applied to a NACA0012 airfoil, which features trailing-edge stall and an error of CL relative to the experiment at CL>1.0 is smaller than 3.5%. The SPF k−v2¯−ω model shows higher accuracy than other turbulence models.

Aerodynamics of plunging airfoil in wind gust

2018 ◽  
Vol 90 (7) ◽  
pp. 1050-1064 ◽  
Author(s):  
Arpan Das ◽  
Shaligram Tiwari
Keyword(s):  
Navier Stokes ◽  
Wind Gust ◽  
Navier Stokes Equation ◽  
Ansys Fluent ◽  
Freestream Velocity ◽  
Content Type ◽  
Naca0012 Airfoil ◽  
Reduced Frequency ◽  
Aerial Vehicle ◽  
Lift And Drag

Purpose Growing application of micro aerial vehicle (MAV) sets in demand for accurate computations of low Reynolds number flows past their wings. The purpose of this study is to investigate the effect of unsteady freestream velocity or wind gust on a harmonically plunging symmetric NACA0012 airfoil at Re = 1,000. The influence of unsteady parameters, such as reduced frequency of plunging motion (0.25 < k < 1.5), non-dimensional plunging amplitude (ho = 0.2) and non-dimensional amplitude of wind gust (0.1 = λ = 0.4) has been studied. Design/methodology/approach Computations have been carried out using commercial software ANSYS Fluent 16.0. To incorporate the plunging motion, the entire reference frame is oscillating, and thereby, a source term is added in the Navier–Stokes equation. Findings The results have been presented in the form of streamlines, vorticity contours, lift and drag signals and their spectra. It is observed that the ratio of plunging frequency to gust frequency (f/fg) has strong influence on periodic characteristics of unsteady wake. It has also been observed that for a fixed plunging amplitude, an increase in value of k results into a change from positive drag to thrust. Practical implications The research has implications in the development of MAV. Originality/value This study is intended to get a better understanding of unsteady parameters associated with gusty flow in flapping wing applications and possible ways to alleviate its adverse effect on it.

scholarly journals Dynamic Stall Characteristics of Pitching Swept Finite-Aspect-Ratio Wings

Fluids ◽  
2021 ◽  
Vol 6 (12) ◽  
pp. 457
Author(s):  
Al Habib Ullah ◽  
Kristopher L. Tomek ◽  
Charles Fabijanic ◽  
Jordi Estevadeordal
Keyword(s):  
Aspect Ratio ◽  
Separation Bubble ◽  
Leading Edge ◽  
Dynamic Stall ◽  
Trailing Edge ◽  
Sweep Angle ◽  
Pitching Motion ◽  
Naca0012 Airfoil ◽  
Phase Average ◽  
Reduced Frequency

An experimental investigation regarding the dynamic stall of various swept wing models with pitching motion was performed to analyze the effect of sweep on the dynamic stall. The experiments were performed on a wing with a NACA0012 airfoil section with an aspect ratio of AR = 4. The experimental study was conducted for chord-based Reynolds number Rec =2×105 and freestream Mach number Ma=0.1. First, a ‘particle image velocimetry’ (PIV) experiment was performed on the wing with three sweep angles, Λ=0o, 15o, and 30o, to obtain the flow structure at several wing spans. The results obtained at a reduced frequency showed that a laminar separation bubble forms at the leading edge of the wing during upward motion. As the upward pitching motion continues, a separation burst occurs and shifts towards the wing trailing edge. As the wing starts to pitch downward, the growing dynamic stall vortex (DSV) vortex sheds from the wing’s trailing edge. With the increasing sweep angle of the wing, the stall angle is delayed during the dynamic motion of the wing, and the presence of DSV shifts toward the wingtip. During the second stage, a ‘turbo pressure-sensitive paint’ (PSP) technique was deployed to obtain the phase average of the surface pressure patterns of the DSV at a reduced frequency, k=0.1. The phase average of pressure shows a distinct pressure map for two sweep angles, Λ=0o, 30o, and demonstrates a similar trend to that presented in the published computational studies and the experimental data obtained from the current PIV campaign.

scholarly journals The Effect of Gurney Flap and Trailing-edge Wedge on the Aerodynamic Behavior of an Axial Turbine Blade

2021 ◽  
Vol 2 (4) ◽  
pp. 293-305
Author(s):  
Mohammad Mahdi Mahzoon ◽  
Masoud Kharati-Koopaee
Keyword(s):  
Angle Of Attack ◽  
Vortex Generator ◽  
Aerodynamic Performance ◽  
Trailing Edge ◽  
Blunt Trailing Edge ◽  
Gurney Flap ◽  
Maximum Increment ◽  
Lift And Drag ◽  
Lift And Drag Coefficient

In this research, the effect of Gurney flap and trailing-edge wedge on the aerodynamic behavior of blunt trailing-edge airfoil Du97-W-300 which is equipped with vortex generator is studied. To do this, the role of Gurney flap and trailing-edge wedge on the lift and drag coefficient and also aerodynamic performance of the airfoil is studied. Validation of the numerical model is performed by comparison of the obtained results with those of experiment. Results show that before stall, Gurney flap leads to the increase in the aerodynamic performance in a wider range of angle of attack. Numerical findings reveal that the maximum increment for the aerodynamic performance is obtained at low angle of attack when trailing-edge wedge is employed. It is found that for the highest considered value of Gurney flap and trailing-edge wedge heights, where the highest values for the lift occur, the higher aerodynamic performance at low angle of attack is obtained when trailing-edge wedge is used and at high angle of attack, the Gurney flap results in a higher aerodynamic performance. It is also shown that when high aerodynamic performance is concerned, addition of Gurney flap to the airfoil leads to the higher value for the lift. Doi: 10.28991/HIJ-2021-02-04-03 Full Text: PDF

Performance Studies on a Wind Turbine Blade Section for Low Wind Speeds With a Gurney Flap

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
M. Rafiuddin Ahmed ◽  
Epeli Nabolaniwaqa
Keyword(s):  
Wind Turbines ◽  
Lift Coefficient ◽  
Flow Characteristics ◽  
Trailing Edge ◽  
Wind Speeds ◽  
Gurney Flap ◽  
Trailing Edge Flaps ◽  
Blade Section ◽  
Low Wind Speeds ◽  
Lift And Drag

The flow characteristics and the lift and drag behavior of a thick trailing-edged airfoil that was provided with fixed trailing-edge flaps (Gurney flaps) of 1–5% height right at the back of the airfoil were studied both experimentally and numerically at different low Reynolds numbers (Re) and angles of attack for possible applications in wind turbines suitable for the wind speeds of 4–6 m/s. The flap considerably improves the suction on the upper surface of the airfoil resulting in a higher lift coefficient. The drag coefficient also increased; however, the increase was less compared with the increase in the lift coefficient, resulting in a higher lift-to-drag ratio in the angles of attack of interest. The results show that trailing-edge flaps can improve the performance of blades designed for low wind speeds and can be directly applied to small wind turbines that are increasingly being used in remote places or in smaller countries.

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