scholarly journals Lift and Drag of Non-conventional Wings at Subsonic Speeds and Zero Angle of Attack - An Experimental Investigation

2018 ◽  
Vol 152 ◽  
pp. 02017
Author(s):  
Abdulkareem Shafiq Mahdi Al-Obaidi ◽  
Ting Chern Wei
Keyword(s):  
Case Studies ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Aerodynamic Performance ◽  
Notch Depth ◽  
Flight Condition ◽  
Wing Model ◽  
Subsonic Speed ◽  
Continue Research ◽  
Lift And Drag

Various non-conventional wing development shows potential in increasing the aerodynamic performance of airplanes. If the non-conventional wing only improves the aerodynamic performance by a small margin, conventional wing is still a better option for airline operators. This provides opportunity to continue research on non-conventional configurations that can greatly saves the fuel consumption. This research was conducted to examine the lift and drag of non-conventional wings at low subsonic speed and low angle of attack. Analytical method based on DATCOM was used to calculate the lift and drag coefficients of non-conventional cranked wing for comparison with experimental results obtained experimentally using Taylor’s wind tunnel (TWT). Experimental lift coefficient shows similar values with the analytical results but experimental drag coefficient had an average difference of 44%. The experimental setup and calibration of TWT were verified and further case studies on nonconventional wing model featuring trailing edge notches were carried out. Analysis of the results from case studies shows that generally the effect of varying the number of notches only had significant effect on drag reduction if the notch depth was higher. For flight condition that does not exceed 4° angle of attack, lower number of notches at higher notch depth had the best aerodynamic performance. On the other hand, for flight condition that requires cruise angle of attack that exceeds 4°, higher number of notches at higher notch depth had the best aerodynamic performance.

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

Alula-Inspired Leading Edge Device for Low Reynolds Number Flight

2016 ◽  
Author(s):  
Boris A. Mandadzhiev ◽  
Michael K. Lynch ◽  
Leonardo P. Chamorro ◽  
Aimy A. Wissa
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
Drag Coefficient ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Leading Edge ◽  
Aerodynamic Performance ◽  
Tip Vortex ◽  
Relative Angle ◽  
Lift And Drag

Robust and predictable aerodynamic performance of unmanned aerial vehicles at the limits of their design envelope is critical for safety and mission adaptability. In order for a fixed wing aircraft to maintain the lift necessary for sustained flight at very low speeds and large angles of attack (AoA), the wing shape has to change. This is often achieved by using deployable aerodynamic surfaces, such as flaps or slats, from the wing leading or trailing edges. In nature, one such device is a feathered structure on birds’ wings called the alula. The span of the alula is 5% to 20% of the wing and is attached to the first digit of the wing. The goal of the current study is to understand the aerodynamic effects of the alula on wing performance. A series of wind tunnel experiments are performed to quantify the effect of various alula deployment parameters on the aerodynamic performance of a cambered airfoil (S1223). A full wind tunnel span wing, with a single alula located at the wing mid-span is tested under uniform low-turbulence flow at three Reynolds numbers, Re = 85,000, 106,00 and 146,000. An experimental matrix is developed to find the range of effectiveness of an alula-type device. The alula relative angle of attack measured measured from the mean chord of the airfoil is varied to modulate tip-vortex strength, while the alula deflection is varied to modulate the distance of the tip vortex to the wing surface. Lift and drag forces were measured using a six axis force transducer. The lift and drag coefficients showed the greatest sensitivity to the the alula relative angle of attack, increasing the normalized lift coefficient by as much as 80%. Improvements in lift are strongly correlated to higher alula angle, with β = 0° – 5°, while reduction in the drag coefficient is observed with higher alula tip deflection ratios and lower β angles. Results show that, as the wing angle of attack and Reynolds number are increased, the overall lift co-efficient improvement is diminished while the reduction in drag coefficient is higher.

Stability Analysis of a Light Aircraft Configuration Using Computational Fluid Dynamics

2012 ◽  
Vol 225 ◽  
pp. 391-396 ◽  
Author(s):  
Mohammed Mahdi ◽  
Yasser A. Elhassan
Keyword(s):  
Numerical Simulation ◽  
Stokes Equations ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Rate Of Change ◽  
Navier Stokes ◽  
Rolling Moment ◽  
Moment Coefficient ◽  
Stability Derivatives ◽  
Lift And Drag

This work aims to simulate and study the flow field around SAFAT-01 aircraft using numerical solution based on solving Reynolds Averaged Navier-Stokes equations coupled with K-ω SST turbulent model. The aerodynamics behavior of SAFAT-01 aircraft developed at SAFAT aviation complex were calculated at different angles of attack and side slip angles. The x,y and z forces and moments were calculated at flight speed 50m/s and at sea level condition. Lift and drag curves for different angles of attack were plotted. The maximum lift coefficient for SAFAT-01 was 1.67 which occurred at angle of attack 16° and Maximum lift to drag ratio (L/D) was 14 which occurred at α=3°, and the zero lift drag coefficient was 0.0342. Also the yawing moment coefficient was plotted for different side slip angles as well as rolling moment. The longitudinal stability derivatives with respect to angle of attack, speed variation (u), rate of pitch (q) and time rate of change of angle of attack were calculated using obtained CFD results. Concerning lateral stability only side slips derivatives were calculated. To validate this numerical simulation USAF Digital DATCOM is used to analyze this aircraft; a comparison between predicted results for this aircraft and Digital DATCOM indicated that this numerical simulation has high ability for predicting the aerodynamics characteristics.

The Effect of Belly-Flap on Aerodynamic Performance of Blended Wing Body Civil Aircraft

2013 ◽  
Vol 378 ◽  
pp. 69-73
Author(s):  
Chen Fang Cai ◽  
Yong Ming Qin ◽  
Jiang Hao Wu
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Angle Of Attack ◽  
Aerodynamic Performance ◽  
Design Parameters ◽  
Flight Safety ◽  
Optimized Design ◽  
Flight Condition ◽  
Civil Aircraft ◽  
Blended Wing Body

The effect of Belly-flap on aerodynamic performance of BWB civil aircraft are investigated in take-off and landing by computational fluid dynamics. And the overload of BWB with Belly-flap also is calculated in the same flight condition. Six parameters are discussed as design parameters of the Belly flap. It is shown that the proper combination of design parameters of Belly-flap can increase the maximum of lift and reduce the angle of attack and nose down moment to improve the flight safety in take-off and landing. When the aircraft with Belly-flap encounters the gust, the maximum overload is very close to 2.5 which are requested by FAR. It is suggested the optimized design of Belly-flap should be done if the Belly-flap is applied in BWB civil aircraft.

scholarly journals Analysis on Flow Field Characteristics of Airfoil in Pitching Motion

2021 ◽  
Vol 2076 (1) ◽  
pp. 012069
Author(s):  
Rui Yin ◽  
Jing Huang ◽  
Zhi-Yuan He
Keyword(s):  
Flow Field ◽  
Drag Coefficient ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Decisive Role ◽  
Aerodynamic Characteristics ◽  
Pitching Motion ◽  
Maximum Value ◽  
Flow Field Characteristics ◽  
Lift And Drag

Abstract Based on CFD, the flow field characteristics of NACA4412 airfoil are analyzed under pitching motion, and its aerodynamic characteristics are interpreted. The results show that streamline changes on the upper surface of the airfoil play a decisive role in the aerodynamic characteristics. The interaction between the vortex leads to fluctuations in the lift and drag coefficients. Under a big angle of attack, the secondary trailing vortex on the upper surface of the airfoil adheres to the trailing edge of the airfoil, resulting in an increased drag coefficient. Under a small angle of attack, the secondary trailing vortex can break away from the airfoil. The lift coefficient reaches the maximum value of 2.961 before the airfoil is turned upside down, and the drag coefficient reaches the maximum value of 1.515 after the airfoil is turned upside down, but the corresponding angles of attack of the two are equal.

scholarly journals Characteristics of Separation and Induced Drag in the Use of Swept-back Wing Unmanned Aerial Vehicle

2021 ◽  
Vol 2117 (1) ◽  
pp. 012013
Author(s):  
S P Setyo Hariyadi ◽  
Sutardi ◽  
Sukahir ◽  
Jamaludin
Keyword(s):  
Lift Coefficient ◽  
Angle Of Attack ◽  
Aerodynamic Performance ◽  
Turbulent Model ◽  
Total Drag ◽  
Aircraft Wings ◽  
Pressure Drag ◽  
Induced Drag ◽  
Aerial Vehicle ◽  
Almost All

Abstract The swept-back wing has been used in almost all aircraft wings. This is necessary to reduce the pressure drag from the wings so that there is an increase in aerodynamic performance. The aerodynamic performance is the ratio between the total drag coefficient and the lift coefficient. This research attempts to explain the swept-back wing phenomenon in unmanned aerial vehicles (UAV) on Eppler 562 airfoil. The numerical simulation uses the k-ε turbulent model at Reynolds number (Re) = 2.34 x 104. Variation of backward swept angle Λ = 0°, 15°, and 30°. The separation growth Λ = 0° occurred more on the wing root, while Λ = 15° and Λ = 30° occurred more on the wingtip. At Λ = 15°, as the angle of attack increases, the area of the separation increases, and the area of the transition towards the separation decreases. The reattach area also has an increase in the area of the trailing edge. At Λ = 30°, with an increase in the angle of attack, there is a shift from the wingtip area to the mid-span. The area of separation and transition to separation has increased significantly. The re-attach area at α = 8o has not been seen, so at α = 12o it has been seen significantly. The vorticity on the x-axis shows Λ = 15°, and Λ = 30° has a wider area while on the z-axis, Λ = 15°, and Λ = 30° have stronger vortex strength. However, in the mid-span, Λ = 0° has a stronger result.

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

Analysing and Optimizing the Aerodynamic Performance of Wind Turbine Blades Using Injected-Air Jets at Variable Frequency and Amplitude for Flow Control

2005 ◽  
Vol 29 (4) ◽  
pp. 331-339 ◽  
Author(s):  
Liu Hong ◽  
Huo Fupeng ◽  
Chen Zuoyi
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Lift Coefficient ◽  
Turbine Blades ◽  
Angle Of Attack ◽  
Leading Edge ◽  
Aerodynamic Performance ◽  
Operating Conditions ◽  
Suction Surface ◽  
Air Jet

Optimum aerodynamic performance of a wind turbine blade demands that the angle of attack of the relative wind on the blade remains at its optimum value. For turbines operating at constant speed, a change in wind speed causes the angle of attack to change immediately and the aerodynamic performance to decrease. Even with variable speed rotors, intrinsic time delays and inertia have similar effects. Improving the efficiency of wind turbines under variable operating conditions is one of the most important areas of research in wind power technology. This paper presents findings of an experimental study in which an oscillating air jet located at the leading edge of the suction surface of an aerofoil was used to improve the aerodynamic performance. The mean air-mass flowing through the jet during each sinusoidal period of oscillation equalled zero; i.e. the jet both blew and sucked. Experiments investigated the effects of the frequency, momentum and location of the jet stream, and the profile of the turbine blade. The study shows significant increase in the lift coefficient, especially in the stall region, under certain conditions. These findings may have important implications for wind turbine technology.

The Analysis about External Compressible Flow around an Aircraft Wing

2014 ◽  
Vol 1044-1045 ◽  
pp. 654-658
Author(s):  
Wei Long ◽  
Zai Shuai Ling ◽  
Zhen Dang
Keyword(s):  
Flow Field ◽  
Velocity Vector ◽  
Delta Wing ◽  
Angle Of Attack ◽  
Flow Simulation ◽  
Aircraft Wing ◽  
Wing Model ◽  
Fluent Simulation ◽  
Lift And Drag ◽  
Variation Tendency

The Steady flow simulation to selected the delta wing model for different angles of attack in the Maher number.The law of flow field changes with the angle of attack is gotten.Through the FLUENT simulation,The variation tendency of coefficient of lift and drag in the different angle of attack is gotten.Further reveals the change rule of Maher number, pressure, velocity and other parameters in the different angle of attack.With increasing angle of attack, Maher number distribution is sparse of the same position increases and the greater numerical.the distribution of velocity vector is sparse of the same position increases and the greater numerical.the pressure distribution is sparse of the same position increases and the greater numerical.

scholarly journals Effect of Angle of Attack on Pressure and Lift Coefficient of ONERA OA206 Wing Model Using Computational Fluid Dynamics Method

2019 ◽  
Vol 2 (2) ◽  
pp. 81
Author(s):  
Resti Anggraeni
Keyword(s):  
Lift Coefficient ◽  
Pressure Coefficient ◽  
Angle Of Attack ◽  
Aircraft Wing ◽  
Wing Model ◽  
Pressure Contour ◽  
The Difference ◽  
The Right ◽  
Expansion Point ◽  
Dynamics Method

In this study, we computed the lift force of the aircraft with ONERA OA206 airfoil type. It was positioned at 0%, 25%, 50%, 75%, and 100% of the wingspan for Angle of Attack (AoA) variations of 0o, 4o, 8o, 12o, and 16o. The research was to determine the effect of AoA on pressure, pressure coefficient (Cp), and lift coefficient (CL) on the ONERA OA206 aircraft wing. It shows that the greater AoA on the result of the pressure contour causes the increase in the difference of span at AoA 0o to 16o t these are 0.25%; 0.26%; 0.43%; 0.52%; and 0.53%. Through the graph of the pressure coefficient (Cp) against x/c, it can be seen that the greater AoA, the expansion point, and the stagnation point will shift to the right with the direction of x/c. In addition, the Cp at the lower is greater than the upper of the airfoil. Based on the research results, it was found that CL at the position of 0% to 50% increased when given AoA from 0o to 12o (CL max) and decreased at AoA = 16o (stall). Meanwhile, CL at 75% to 100% increased when given AoA from 0o to 8o (CL max) and decreased at AoA = 12o (stall). With these results, it can be concluded that the maximum AoA that can be applied to the wing of the ONERA OA206 aircraft is 8o. The closer to the end position of the airfoil, the higher the CL measured.

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