Analysis Influence of Trailing Edge Modification on Aerodynamic Performance of Airfoils for Wind Turbine

2012 ◽  
Vol 220-223 ◽  
pp. 900-904 ◽  
Author(s):  
Shang Ke Yuan ◽  
Ren Nian Li
Keyword(s):  
Pressure Distribution ◽  
Characteristic Curve ◽  
Lift Coefficient ◽  
Simple Algorithm ◽  
Aerodynamic Characteristics ◽  
Trailing Edge ◽  
Airfoil Surface ◽  
Gurney Flap ◽  
Aerodynamic Performances ◽  
Volume Method

The airfoil NACA 4412 commonly employed in wind turbines is modified by attaching a Gurney flap with length of 2% chord at its trailing edge and its remodeled form as well. The SIMPLE algorithm of finite volume method and software FLUENT are respectively used to carry out numerical computation of aerodynamic performances of above-mentioned three airfoils (including the un-modified one), so that their aerodynamic characteristics, pressure distribution on their surface, and streamline around them are obtained for different angles of attack. It is shown by the computation result that the modified airfoils will result in such a strong downwash effect that the pressure distribution on airfoil surface is remarkably altered, the lift coefficient and as well as the slope of lift-drag characteristic curve are increased, and meantime the airfoil stalling is greatly postponed.

Research on Wind Turbine Airfoils Aerodynamic Performance of Trailing Edge Modification

2015 ◽  
Vol 741 ◽  
pp. 554-557
Author(s):  
Shang Ke Yuan ◽  
Zi Qin Zhao
Keyword(s):  
Pressure Distribution ◽  
Lift Coefficient ◽  
Aerodynamic Characteristics ◽  
Trailing Edge ◽  
Airfoil Surface ◽  
Computation Result ◽  
Surface Pressure Distribution ◽  
Gurney Flap ◽  
Aerodynamic Performances ◽  
Turbine Airfoils

The airfoil commonly employed in wind turbines is modified by attaching a Gurney flap with length of 2% chord at its trailing edge and its remodeled form as well,but it showed special aerodynamic characteristics.The software FLUENT are respectively used to carry out numerical computation of aerodynamic performances of above-mentioned three airfoils, so that their aerodynamic characteristics, surface pressure distribution, and streamline around them are obtained for different angles of attack. It is shown by the computation result that the modified airfoils will result in such a strong downwash effect and the pressure distribution on airfoil surface is remarkably altered, the lift coefficient, and meantime the airfoil stalling is greatly postponed,but the airfoil of Gurney flap shown the characteristics of opposite.

Numerical Simulation on Aerodynamic of the Wing in Ground Effect

2012 ◽  
Vol 546-547 ◽  
pp. 200-205
Author(s):  
Rong Wu ◽  
Feng Liang
Keyword(s):  
Numerical Simulation ◽  
Drag Coefficient ◽  
Finite Volume Method ◽  
Lift Coefficient ◽  
Ground Effect ◽  
Simulation Method ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performances ◽  
Volume Method ◽  
Drag Ratio

Aerodynamic characteristics of the wing NACA5312 in ground effect are investigated with the numerical simulation method. The N-S equations and the k-ε turbulence model are solved by the finite volume method in CFD software. This paper computes the flying states under different clearances, steam velocities and angles of attack. Compared with results under the unbounded flow, it studies the relations between the aerodynamic performances and the angles of attack, the steam velocity, and the relative heights. The aerodynamic performances include the lift coefficient, drag coefficient, and lift-drag ratio.

Lift Control Using MEMS-Based Moving Trailing-Edge Tabs

2002 ◽  
Author(s):  
C. P. van Dam ◽  
C. Bauer ◽  
D. T. Yen Nakafuji
Keyword(s):  
Lift Coefficient ◽  
Aerodynamic Characteristics ◽  
Trailing Edge ◽  
Aircraft Wings ◽  
Lifting Surface ◽  
Lifting Surfaces ◽  
Lift Control

Micro-electro-mechanical (MEM) translational tabs are introduced for active lift control on aircraft. These tabs are mounted near the trailing edge of lifting surfaces such as aircraft wings and tails, deploy approximately normal to the surface, and have a maximum deployment height on the order of one percent of the section chord. Deployment of the tab effectively changes the sectional camber, thereby changing the aerodynamic characteristics of a lifting surface. Tabs with said deployment height generate a change in the section lift coefficient of approximately ±0.3. The microtab design and the techniques used to fabricate and test the tabs are presented.

A Thin Aerofoil of Small Camber in a Non-Uniform Flow

1967 ◽  
Vol 71 (675) ◽  
pp. 214-216
Author(s):  
L. N. Nigam
Keyword(s):  
Pressure Distribution ◽  
Stream Function ◽  
Constant Velocity ◽  
Direct Problem ◽  
Lift Coefficient ◽  
Aerodynamic Characteristics ◽  
Angle Of Incidence ◽  
Pitching Moment ◽  
Image Position ◽  
General Profile

The direct problem of aerodynamics (profile of the aerofoil is given—calculate the aerodynamic characteristics) has been studied for thin aerofoils with small camber. Given the undisturbed stream functionV, ω, α being the constant velocity, vorticity and angle of incidence respectively, the pressure distribution, lift coefficient and pitching moment have been calculated for a general profile.

Performance of S-Cambered Profiles With Cut-Off Trailing Edges

1994 ◽  
Vol 116 (3) ◽  
pp. 522-527 ◽  
Author(s):  
Baby Chacko ◽  
V. Balabaskaran ◽  
E. G. Tulapurkara ◽  
H. C. Radha Krishna
Keyword(s):  
Lift Coefficient ◽  
Forward Direction ◽  
Aerodynamic Characteristics ◽  
Reverse Direction ◽  
Flow Conditions ◽  
Reversed Flow ◽  
Trailing Edge ◽  
Reverse Mode ◽  
Trailing Edges

The aerodynamic characteristics of an S-cambered profile are studied under forward and reversed flow conditions. The profile chord is cut by 3, 6, and 9 percent of the chord at the sharp trailing edge end and the performances of these profiles are compared. It is found that with increase in length of cutting the lift coefficient increases in forward direction and decreases in reverse direction of flow. Cutting off the sharp trailing edge improves the lift-drag characteristics in forward mode and deteriorates in the reverse mode.

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.

Unsteady aerodynamic characteristics of a morphing wing

2018 ◽  
Vol 91 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Jinwu Xiang ◽  
Kai Liu ◽  
Daochun Li ◽  
Chunxiao Cheng ◽  
Enlai Sha
Keyword(s):  
Lift Coefficient ◽  
Angle Of Attack ◽  
Large Angle ◽  
Unsteady Aerodynamics ◽  
Aerodynamic Characteristics ◽  
Static Case ◽  
Morphing Wing ◽  
Trailing Edge ◽  
Content Type ◽  
Unsteady Aerodynamic

Purpose The purpose of this paper is to investigate the unsteady aerodynamic characteristics in the deflection process of a morphing wing with flexible trailing edge, which is based on time-accurate solutions. The dynamic effect of deflection process on the aerodynamics of morphing wing was studied. Design/methodology/approach The computational fluid dynamic method and dynamic mesh combined with user-defined functions were used to simulate the continuous morphing of the flexible trailing edge. The steady aerodynamic characteristics of the morphing deflection and the conventional deflection were studied first. Then, the unsteady aerodynamic characteristics of the morphing wing were investigated as the trailing edge deflects at different rates. Findings The numerical results show that the transient lift coefficient in the deflection process is higher than that of the static case one in large angle of attack. The larger the deflection frequency is, the higher the transient lift coefficient will become. However, the situations are contrary in a small angle of attack. The periodic morphing of the trailing edge with small amplitude and high frequency can increase the lift coefficient after the stall angle. Practical implications The investigation can afford accurate aerodynamic information for the design of aircraft with the morphing wing technology, which has significant advantages in aerodynamic efficiency and control performance. Originality/value The dynamic effects of the deflection process of the morphing trailing edge on aerodynamics were studied. Furthermore, time-accurate solutions can fully explore the unsteady aerodynamics and pressure distribution of the morphing wing.

Investigation on Propeller Slipstream by Using an Unstructured Rans Solver Based on Overlapping Grids

2017 ◽  
Vol 34 (2) ◽  
pp. 89-101 ◽  
Author(s):  
X. Q. Gong ◽  
M. S. Ma ◽  
J. Zhang ◽  
J. Tang
Keyword(s):  
Pressure Distribution ◽  
Stokes Equations ◽  
Lift Coefficient ◽  
Linear Interpolation ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Overlapping Grids ◽  
Moment Coefficient ◽  
Grid Technique

AbstractBased on unstructured hybrid grid and dynamic overlapping grid technique, numerical simulations of Unsteady Reynolds Averaged Navier-Stokes equations were performed and investigation on isolated propeller aerodynamic characteristics and effects of propeller slipstream on turboprops were undertaken. The computational grid consisted of rotational subzone of propeller and stationary major-zone of aircraft, and walls criterion was used in the automatic hole-cutting procedure. Distance weight interpolation and tri-linear interpolation were developed to transfer information between the rotational and stationary subzones. The boundaries of overlapping grids were optimized for fixed axis rotation. The governing equations were solved by dual-time method and Lower Upper-Symmetric Gauss-Seidel method. The method and grid technique were verified by isolated propeller configuration and the computational results were in well agreement with the experimental data. The grid independence was studied to establish the numerical results. Finally, the flow around a turboprop case was simulated and the influence of propeller slipstream was presented by analyzing the surface pressure contours, profile pressure distribution, vorticity contours and profile streamline. It's indicated that the slipstream accelerates and rotates the free stream flow, changing the local angle of attack, enhancing the downwash effects, affecting the pressure distribution on wing and horizontal tail, as well as increasing the drag coefficient, pitching moment coefficient and the slope of lift coefficient.

scholarly journals Experimental Study on Aerodynamic Characteristics of a Gurney Flap on a Wind Turbine Airfoil under High Turbulent Flow Condition

2020 ◽  
Vol 10 (20) ◽  
pp. 7258 ◽  
Author(s):  
Junwei Yang ◽  
Hua Yang ◽  
Weijun Zhu ◽  
Nailu Li ◽  
Yiping Yuan
Keyword(s):  
Wind Tunnel ◽  
Turbulent Flow ◽  
Lift Coefficient ◽  
Leading Edge ◽  
Aerodynamic Characteristics ◽  
Chord Length ◽  
Turbulence Level ◽  
Gurney Flaps ◽  
Gurney Flap ◽  
Delay Phenomenon

The objective of the current work is to experimentally investigate the effect of turbulent flow on an airfoil with a Gurney flap. The wind tunnel experiments were performed for the DTU-LN221 airfoil under different turbulence level (T.I. of 0.2%, 10.5% and 19.0%) and various flap configurations. The height of the Gurney flaps varies from 1% to 2% of the chord length; the thickness of the Gurney flaps varies from 0.25% to 0.75% of the chord length. The Gurney flap was vertical fixed on the pressure side of the airfoil at nearly 100% measured from the leading edge. By replacing the turbulence grille in the wind tunnel, measured data indicated a stall delay phenomenon while increasing the inflow turbulence level. By further changing the height and the thickness of the Gurney flap, it was found that the height of the Gurney flap is a very important parameter whereas the thickness parameter has little influence. Besides, velocity in the near wake zone was measured by hot-wire anemometry, showing the mechanisms of lift enhancement. The results demonstrate that under low turbulent inflow condition, the maximum lift coefficient of the airfoil with flaps increased by 8.47% to 13.50% (i.e., thickness of 0.75%), and the Gurney flap became less effective after stall angle. The Gurney flap with different heights increased the lift-to-drag ratio from 2.74% to 14.35% under 10.5% of turbulence intensity (i.e., thickness of 0.75%). However, under much a larger turbulence environment (19.0%), the benefit to the aerodynamic performance was negligible.

scholarly journals Effect of Gurney Flap Geometry on a S809 Airfoil

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Li-Shu Hao ◽  
Yong-Wei Gao
Keyword(s):  
Numerical Simulation ◽  
Lift Force ◽  
Lift Coefficient ◽  
Simulation Method ◽  
Aerodynamic Characteristics ◽  
Pitching Moment ◽  
Gurney Flaps ◽  
Gurney Flap ◽  
Linear And Nonlinear ◽  
Better Than

In this paper, the effect of Gurney flap shapes on wind turbine blade airfoil S809 has been studied by numerical simulation. First, the O-type grid is used in the numerical simulation. By comparing with experimental data, such as the lift force, the drag coefficient, and the pressure distribution, the accuracy of the simulation method is validated. Second, the research on the widths of three kinds of rectangular Gurney flaps at the trailing edge of the S809 airfoil is carried out. Rectangular Gurney flaps can considerably increase the lift in both the linear and nonlinear sections, and the maximum lift coefficient can be increased by 20.65%. In addition, the drag and the pitching moment are increased. However, the width of the rectangular Gurney flap has a small impact on the lift, the drag, and the pitching moment. Finally, the effects of rectangular and triangular Gurney flaps on the aerodynamic characteristics of the S809 airfoil are compared. The results show that the triangular flaps can obtain an increase of maximum lift coefficient by 28.42%, which is better than 16.31% of the rectangular flaps.

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