scholarly journals Gurney Flap Implementation on a DU91W250 Airfoil

Proceedings ◽  
2018 ◽  
Vol 2 (23) ◽  
pp. 1448 ◽  
Author(s):  
Iñigo Aramendia ◽  
Aitor Saenz-Aguirre ◽  
Unai Fernandez-Gamiz ◽  
Ekaitz Zulueta ◽  
Jose Manuel Lopez-Guede ◽  
...  
Keyword(s):  
Flow Control ◽  
Numerical Study ◽  
Lift Coefficient ◽  
Optimization Technique ◽  
Electrical Power ◽  
Aerodynamic Performance ◽  
Control Element ◽  
Mechanical Fatigue ◽  
Gurney Flap ◽  
Fatigue Loads

The increasing capability of Wind Turbine (WT) based power generation systems has derived in an increment of the WT rotor diameter, i.e., longer rotor blades. This results in an increase of the electrical power generated but also in instabilities in the operation of the WT, especially due to the mechanical fatigue loads generated in its elements. In this context, flow control has appeared as a solution to improve the aerodynamic performance of the blades. These devices not only increase lift coefficient but also reduce mechanical fatigue loads. This paper presents a detailed numerical analysis of the effects of placing a passive flow control element, a Gurney Flap (GF), in a DU91W250 airfoil. Moreover, a numerical study of the influence of the GF length on the aerodynamic performance of the blade has been carried out. This study is considered as a basis for the development of an optimization technique of the GF length for long WT blades.

scholarly journals An Experimental Analysis on the Effects of Stagger on the Aerodynamic Forces of Tandem Wings

AVIA ◽  
2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Y Parlindungan ◽  
S Tobing
Keyword(s):  
Experimental Analysis ◽  
Numerical Study ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Aerodynamic Performance ◽  
Open Loop ◽  
Aerodynamic Forces ◽  
Subsonic Wind Tunnel ◽  
Lift And Drag ◽  
Naca 0012

This study is inspired by the flapping motion of natural flyers: insects. Many insects have two pairs of wings referred as tandem wings. Literature review indicates that the effects of tandem wing are influenced by parameters such as stagger (the stream-wise distance between the aerodynamic center of the front and the rear airfoil), angle-of-attack and flow velocity. As a first stage, this study focuses on the effects of stagger (St) on the aerodynamic performance of tandem wings. A recent numerical study of stagger on tandem airfoils in turbulent flow (Re = 6000000) concluded that a larger stagger resulted in a decrease in lift force, and an increase in drag force. However, for laminar flow (Re = 2000), increasing the stagger was not found to be detrimental for aerodynamic performance. Another work also revealed that the maximum lift coefficient for a tandem configuration decreased with increasing stagger. The focus of this study is to perform an experimental analysis of tandem two-dimensional (2D) NACA 0012 airfoils. The two airfoils are set at the same angle-of-attack of 0° to 15° with 5° interval and three variations of stagger: 1c, 1.5c and 2c. The experiments are conducted using an open-loop-subsonic wind tunnel at a Reynolds number of 170000. The effects of St on the aerodynamic forces (lift and drag) are analyzed

scholarly journals Numerical study on the steady suction active flow control of hydrofoil in the profile of the blended-wing-body underwater glider

2021 ◽  
Vol 39 (4) ◽  
pp. 801-809
Author(s):  
Xiaoxu Du ◽  
Lianying Zhang
Keyword(s):  
Flow Control ◽  
Numerical Study ◽  
Active Flow Control ◽  
Lift Coefficient ◽  
Leading Edge ◽  
Hydrodynamic Performance ◽  
Flow State ◽  
Underwater Glider ◽  
Blended Wing Body ◽  
Active Flow

The hydrodynamic performance of the blended-wing-body underwater glider can be improved by opening a hole on the surface and applying the steady suction active flow control. In order to explore the influence law and mechanism of the steady suction active flow control on the lift and drag performance of the hydrofoil, which is the profile of the blended-wing-body underwater glider, based on the computational fluid dynamics (CFD) method and SST k-ω turbulence model, the steady suction active flow control of hydrofoil under different conditions is studied, which include three suction factors: suction angle, suction position and suction ratio, as well as three different flow states: no stall, critical stall and over stall. Then the influence mechanism in over stall flow state is further analyzed. The results show that the flow separation state of NACA0015 hydrofoil can be effectively restrained and the flow field distribution around it can be improved by a reasonable steady suction, so as to the lift-drag performance of NACA0015 hydrofoil is improved. The effect of increasing lift and reducing drag of steady suction is best at 90° suction angle and symmetrical about 90° suction angle, and it is better when the steady suction position is closer to the leading edge of the hydrofoil. In addition, with the increase of the suction ratio, the influence of steady suction on the lift coefficient and drag coefficient of hydrofoil is greater.

Dynamic stall of an airfoil with different mounting angle of gurney flap

2020 ◽  
Vol 92 (7) ◽  
pp. 1037-1048
Author(s):  
Mehran Masdari ◽  
Milad Mousavi ◽  
Mojtaba Tahani
Keyword(s):  
Lift Coefficient ◽  
Oscillation Amplitude ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Dynamic Stall ◽  
Content Type ◽  
Naca0012 Airfoil ◽  
Gurney Flap ◽  
Stall Angle ◽  
Axis Length

Purpose One of the best methods to improve wind turbine aerodynamic performance is modification of the blade’s airfoil. The purpose of this paper is to investigate the effects of gurney flap geometry and its oscillation parameters on the pitching NACA0012 airfoil. Design/methodology/approach This numerical solution has been carried out for different cases of gurney flap mounting angles, heights, reduced frequencies and oscillation amplitudes, then the results were compared to each other. The finite volume method was used for the discretization of the governing equations, and the PISO algorithm was used to solve the equations. Also, the “SST” was adopted as the turbulence model in the simulation. Findings In this paper, the different parameters of gurney flap were investigated. The results showed that the best range of gurney flap height are between 1 and 3.2% of chord and the best ratio of lifting to drag coefficient is achieved in gurney flap with an angle of 90° relative to the chord direction. The dynamic stall angle of the airfoil with gurney flap decreases were compared to without gurney flap. Earlier LEV formation can be one of the main reasons for decreasing the dynamic stall angle of the airfoil with gurney flap. Increasing the reduced frequency and oscillation amplitude causes rising of maximum lift coefficient and consequently lift curve slope. Moreover, gurney flap with mounting angle has a lower hinge moment than the gurney flap without mounting angle but with the same vertical axis length. So, there is more complexity in structural design concerning the gurney flap without mounting angle. Practical implications Improving aerodynamic efficiency of airfoils is vital for obtaining more output power in VAWTs. Gurney flaps are one of the best mechanisms to increase the aerodynamic performance of the airfoil and increases the efficiency of VAWTs. Originality/value Investigating the hinge moment on the connection point of the airfoil, gurney flap and try to compare the gurney flap with and without angle.

Numerical Study of Unsteady Pulsed Suction through Endwall Bleed Holes in a Highly Loaded Compressor Cascade

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Hongxin Zhang ◽  
Shaowen Chen ◽  
Songtao Wang ◽  
Zhongqi Wang
Keyword(s):  
Flow Control ◽  
Flow Rate ◽  
Numerical Study ◽  
Aerodynamic Performance ◽  
Compressor Cascade ◽  
Skew Angle ◽  
Unsteady Aerodynamic ◽  
Aerodynamic Parameters ◽  
Suction Flow ◽  
Highly Loaded

AbstractUnsteady pulsed suction (UPS) was applied as an unsteady flow control (UFC) technique in a certain highly loaded compressor cascade to control the flow separations. Only two bleed holes symmetrically mounted on the endwalls (one on the upper endwall and another on the lower endwall) were set up to achieve steady constant suction (SCS) and UPS. The improvements in aerodynamic performance by SCS and UPS under different time-averaged suction flow rates are firstly investigated and compared. The related unsteady aerodynamic parameters of UPS such as excitation frequency, excitation location, pitch angle, and skew angle are discussed and analyzed in detail. The results show that UPS can provide a better flow control effect than SCS with the same time-averaged dimensionless suction flow rate in the control of flow separation. The aerodynamic performance of compressor cascades can be significantly enhanced by UPS when unsteady aerodynamic parameters are in their optimum ranges. Based on the optimum parameters for UPS, the total pressure loss coefficient is reduced by 19 % only with the time-averaged dimensionless suction flow ratems=0.4 %.

scholarly journals Numerical Investigation of Aerodynamic Characteristics of NACA 4312 Airfoil with Gurney Flap

2021 ◽  
pp. 1-8
Author(s):  
Subah Mubassira ◽  
Farhana Islam Muna ◽  
Mohammad Ilias Inam
Keyword(s):  
Flow Separation ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Reynold Number ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Chord Length ◽  
Ansys Fluent ◽  
Gurney Flap ◽  
Sst Model

This paper presents a two-dimensional Computational Fluid Dynamics (CFD) analysis on the effect of gurney flap on a NACA 4312 airfoil in a subsonic flow. These numerical simulations were conducted for flap heights 1.5%, 1.75%, 2% and 3% of chord length at fixed Reynold Number, Re (5×105) for different angle of attack (0o ~16o). ANSYS Fluent commercial software was used to conduct these simulations. The flow was considered as incompressible and K-omega Shear Stress Transport (SST) model was selected. The numerical results demonstrate that lift coefficient increase up to around 12o AoA (angle of attack) for NACA 4312 with and without gurney flap. For every AoA lift coefficient and drag coefficient presented proportionate behavior with flap height. However, lift co-efficient was decreased after around  angle of attack due to flow separation. Maximum lift to drag ratio was found at around 4o AoA for every flap length and airfoil with flap of 1.5%C (chord length) had shown the most optimized aerodynamic performance through the analysis. This study concluded that airfoil with gurney flap displayed enhanced aerodynamic performance than the airfoil without gurney flap due to the delay in flow separation.

Surface suction on aerofoil aerodynamic characteristics at transonic speeds

1998 ◽  
Vol 212 (5) ◽  
pp. 339-351 ◽  
Author(s):  
N Qin ◽  
Y Zhu ◽  
D I A Poll
Keyword(s):  
Flow Control ◽  
Numerical Study ◽  
Active Flow Control ◽  
Effective Means ◽  
Active Surface ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Surface Suction ◽  
Lift And Drag ◽  
Active Flow

This paper presents a numerical study of the effects of an active flow control through surface suction on shock boundary layer interactions over transonic aerofoils. Two different aerofoils were studied. Firstly, for the purpose of validation, an NACA64A010 aerofoil with a trailing edge flap was investigated and the numerical results were compared with experimental data with and without suction for surface pressure distributions and lift and drag coefficients. Grid sensitivity has also been studied regarding the numerical accuracy. The second geometry was an RAE9647 aerofoil, which was designed for superior aerodynamic performance when applied to a helicopter rotor blade. An active surface was used to prevent or alleviate shock-induced separation. The suction strength and location were varied to determine the effect on aerodynamic performance and to provide an effective means of suppressing undesirable flow features. In both cases, increases in both lift and drag were observed when surface suction was applied. However, the benefit of suction appeared in the form of a substantial increase in the lift-drag ratio. It was also found that the shock location and strength are very sensitive to the suction location and strength. Two different mechanisms for active flow control over transonic aerofoils are discussed.

Numerical Study of the Roughness Influence on NACA 63-430 Profile Aerodynamic Performance

2016 ◽  
Vol 10 (4) ◽  
pp. 231
Author(s):  
Abdekarim Tebbal ◽  
Fethi Saidi ◽  
Boualem Noureddine ◽  
Bachir Imine ◽  
Benameur Hamoudi
Keyword(s):  
Numerical Study ◽  
Aerodynamic Performance

CFD study of aerodynamic performance of non-pneumatic tyre with hexagonal spokes

2021 ◽  
pp. 095440702110131
Author(s):  
Daksh Bhatia ◽  
Praneeth KR ◽  
Babu Rao Ponangi ◽  
Meghana Athadkar ◽  
Carine V Dsouza
Keyword(s):  
Comparative Study ◽  
Lift Coefficient ◽  
Aerodynamic Performance ◽  
Practical Implementation ◽  
Air Velocity ◽  
Aerodynamic Forces ◽  
Steering Angle ◽  
Camber Angle ◽  
Drag And Lift ◽  
Yaw Angle

Non-pneumatic tyres (NPT) provide a greater advantage over the pneumatic type owing to their construct which increases the reliability of the tyre operation and effectively reduces maintenance involved. Analysing the aerodynamic forces acting on a NPT becomes a crucial factor in understanding it’s suitability for practical implementation. In the present work, the aerodynamic performance of a NPT using CFD tool – SimScale® is studied. This work includes a comparative study of a pneumatic tyre, a NPT with wedge spokes and a NPT with hexagonal spokes (NPT-HS). The effect of air velocity, steering (yaw) angle and camber angle on the aerodynamic performance of the NPT-HS is evaluated using CFD. By increasing the steering angle from 0° to 15°, the lift coefficient decreases by 37% approximately at all velocities. Whereas drag coefficient initially decreases by 21% till 7.5° steering angle and then starts increasing. Increasing camber angle from 0° to 1.5°, both drag and lift coefficients goes on decreasing by approximately 7% and 27% respectively.

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