Aerodynamic Properties of Avian Flight as a Function of Wing Shape

2005 ◽  
Author(s):  
Andrew I. March ◽  
Charles W. Bradley ◽  
Ephraim Garcia
Keyword(s):  
Bird Species ◽  
Commercial Aircraft ◽  
Morphing Aircraft ◽  
Avian Flight ◽  
Induced Drag ◽  
Aerodynamic Properties ◽  
Flight Regimes ◽  
Long Endurance ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Presently, all man-made aircraft are optimized for one specific flight regime. Commercial aircraft fly at a specific cruising altitude at which they are most efficient, and military aircraft, which require excellent performance in many flight regimes are designed to be ‘good’ at all of them. A new concept in aviation, morphing aircraft, or aircraft that can fully change their shape, will allow for optimization at nearly any flight regime. This concept has been millennia in the making, well before mankind. Looking to various bird species, tails and wings can completely change shape to optimize their morphology for a given flight regime. Raptors, especially, have mastered the air in that they must out compete and overcome other birds while hunting. For soaring, these birds spread their wings fully to maximize their lift to drag ratio and maintain a low energy, long endurance flight. To maximize speed in a dive they will bring their wings close to their bodies to minimize drag. This study seeks to quantify the aerodynamic properties of the wing. From bird wings the aerodynamic properties of shape changing elastic structures can be understood. The coefficient of lift versus angle of attack plot of a bird wing is not like that of a typical airfoil, it has no distinct point where the wing stalls, instead the bird wing will twist into the flow. Additionally, the induced drag of an avian wing is significantly less than the theoretical induced drag on a wing predicted by the aspect ratio. A flow visualization around the slotted wingtips of a bird reveals smooth streaklines near the primary feathers. These feathers are canted downward and accordingly generate lift in the thrust direction of the wing, which acts to reduce the induced drag on the wing.

scholarly journals Numerical and Experimental Investigation on the Aerodynamic performance of roller Airfoil

2018 ◽  
Vol 7 (4.10) ◽  
pp. 637 ◽  
Author(s):  
M. Senthil Kumar ◽  
R. Vijayanandh ◽  
N. Kaviarasan ◽  
R. Dinesh Kumar ◽  
I. Adrin Issai Arasu ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Laminar Flow ◽  
Performance Enhancement ◽  
Aerodynamic Performance ◽  
Flight Performance ◽  
Induced Drag ◽  
Aerodynamic Properties ◽  
Morphing Technology ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Prevailing norm is a fixed wing in a conventional aircraft, but the prospect appears bright for developing wings that could yield better aerodynamic properties with a change in the form and shape, this may have a wider application in future aviation. The main objective of this paper is to probe such a morphing technology in wings to improve their aerodynamic performance while operating at various cruise conditions. The airfoil is equipped with a rolling mechanism on its upper surface, operated by custom- designed controllers. This roller airfoil model will generate higher lift at low angles of attack and substantially increase flight performance, leading to the evolution of a create multiple-regime, aerodynamically efficient aircraft. This paper aims to compare the performance enhancement of roller airfoil over a conventional airfoil, by increasing the velocity at the upper surface of the airfoil to increase the lift to drag ratio using typical engineering analyses. The cambered airfoil chosen here is NACA 4412. Morphing concept brings about the improvement due to a reduction in lift-induced drag by promoting large laminar flow run on the upper surface of the wing.  

Kinematics of diving Atlantic puffins (Fratercula arctica L.):evidence for an active upstroke

2002 ◽  
Vol 205 (3) ◽  
pp. 371-378
Author(s):  
L. Christoffer Johansson ◽  
Björn S. Wetterholm Aldrin
Keyword(s):  
Three Dimensional ◽  
Fratercula Arctica ◽  
Induced Drag ◽  
Video Images ◽  
Hand Bones ◽  
On Line ◽  
Oscillating Motion ◽  
Drag Ratio ◽  
Wing Tip ◽  
Lift To Drag Ratio

SUMMARY To examine the propulsion mechanism of diving Atlantic puffins (Fratercula arctica), their three-dimensional kinematics was investigated by digital analysis of sequential video images of dorsal and lateral views. During the dives of this wing-propelled bird, the wings are partly folded, with the handwings directed backwards. The wings go through an oscillating motion in which the joint between the radius-ulna and the hand bones leads the motion, with the wing tip following. There is a large rotary motion of the wings during the stroke, with the wings being pronated at the beginning of the downstroke and supinated at the end of the downstroke/beginning of the upstroke. Calculated instantaneous velocities and accelerations of the bodies of the birds show that, during the downstroke, the birds accelerate upwards and forwards. During the upstroke, the birds accelerate downwards and, in some sequences analysed, also forwards, but in most cases the birds decelerate. In all the upstrokes analysed, the forward/backward acceleration shows the same pattern, with a reduced deceleration or even a forward acceleration during ‘mid’ upstroke indicating the production of a forward force, thrust. Our results show that the Atlantic puffin can use an active upstroke during diving, in contradiction to previous data. Furthermore, we suggest that the partly folded wings of diving puffins might act as efficient aft-swept wingtips, reducing the induced drag and increasing the lift-to-drag ratio. A movie is available on-line.

scholarly journals Aerodynamic Performance Analysis of a Variable Sweep Wing for Commercial Aircraft Applications

2021 ◽  
Vol 1 (1) ◽  
pp. 31-37
Author(s):  
Radhakrishnan P ◽  
Ramanan G ◽  
Chandan Gowda H R ◽  
Meghana C K ◽  
Chaithra A N
Keyword(s):  
Delta Wing ◽  
Aerodynamic Performance ◽  
Commercial Aircraft ◽  
Supersonic Speed ◽  
Ansys Fluent ◽  
Morphing Aircraft ◽  
Aircraft Performance ◽  
Fluent Software ◽  
Solid Works ◽  
Flight Regimes

This study presents a detailed study on wing and its configurations and the morphing techniques for the wing. The morphing methods of the wing such as variable chord, variable span variable cambers have been studied in detail. In this study in detail about the effects of morphable sweep wing, the commercial aircraft wing has been designed and it‘s been modelled using the solid works software. To study the aerodynamic performance the wing, the wing has been analysed in ANSYS Fluent software and the results are interpreted in detail to analyze the effect of wing and its shapes. From the results it‘s been clear that at low speed (Mach=0.8) straight wing has high L/D ratio and at the sonic speed (Mach=1) sweep wing has higher L/D ratio and in Supersonic Speed (Mach=1.2) delta wing tends to have higher L/D ratio. Based on these results the wing can be morphed to the configurations to obtain a better performance in each flight regime. Based on these morphing, aircraft performance can be improved in all flight regimes.

scholarly journals RESEARCH OF WING DIHEDRAL ANGLE EFFECT ON AERODYNAMIC PERFORMANCE OF TANDEM-WING UNMANNED AERIAL VEHICLE

2013 ◽  
pp. 90-101
Author(s):  
І. С. Кривохатько
Keyword(s):  
Dihedral Angle ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Theoretical Explanation ◽  
Wing Span ◽  
Induced Drag ◽  
Rear Wing ◽  
Angle Effect ◽  
Drag Ratio ◽  
Lift To Drag Ratio

In the last decade folding tube launch UAV became common, for which aerodynamic scheme "tandem" is reasonable. By the time tandem-wing aerodynamic characteristics are researched much less than ones of traditional scheme. Particularly it concerns wing dihedral angle effect on lift-to-drag ratio about which no quantitative data were found.Forward or rear wing dihedral angle appearance result in circulation redistribution and changing of rear wing induced drag. Rear wing dihedral angle effect on longitudinal aerodynamic performance of tandem-wing UAV model was researched through wind tunnel experiment. Geometry variables were forward and rear wing spans, rear wing dihedral angle and longitudinal stagger. Lift, drag and longitudinal moment coefficients were defined.The possibility of lift-to-drag ratio increasing at cruise regime was proofed. Rear wing negative dihedral angle application is able to increase maximal lift-to-drag ratio by more than 1.0 or about 10 %.It was found that wing dihedral angle effectiveness depends from relation of forward and rear wing spans and from longitudinal stagger. Longitudinal stagger increasing results in dihedral angle effectiveness falling if forward wing span is higher than rear wing. For bigger rear wing span increasing of longitudinal stagger results in dihedral angle effectiveness gaining. The hypothesis was declared that proposes theoretical explanation of experimentally founded dependencies.Also dihedral angle appearance increases lift slope because of rear wing carrying capacity gain and has almost no influence on maximal lift coefficient.All dependencies founded for rear wing negative dihedral angle are correct for forward wing positive dihedral angle except the last one is increasing longitudinal and lateral stability.

CFD analysis of variable geometric angle winglets

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ali Hussain Kazim ◽  
Abdullah Hamid Malik ◽  
Hammad Ali ◽  
Muhammad Usman Raza ◽  
Awais Ahmad Khan ◽  
...  
Keyword(s):  
Aerodynamic Performance ◽  
Sweep Angle ◽  
Content Type ◽  
Wing Model ◽  
Induced Drag ◽  
Computational Fluid Dynamics Analysis ◽  
Attached Flow ◽  
Drag Ratio ◽  
Fuel Costs ◽  
Lift To Drag Ratio

Purpose Winglets play a major role in saving fuel costs because they reduce the lift-induced drag formed at the wingtips. The purpose of this paper is to obtain the best orientation of the winglet for the Office National d’Etudes et de Recherches Aérospatiales (ONERA) M6 wing at Mach number 0.84 in terms of lift to drag ratio. Design/methodology/approach A computational fluid dynamics analysis of the wing-winglet configuration based on the ONERA M6 airfoil on drag reduction for different attack angles at Mach 0.84 was performed using analysis of systems Fluent. First, the best values of cant and sweep angles in terms of aerodynamic performance were selected by performing simulations. The analysis included cant angle values of 30°, 40°, 45°, 55°, 60°, 70° and 75°, while for the sweep angles 35°, 45°, 55°, 65° and 75° angles were used. The aerodynamic performance was measured in terms of the obtained lift to drag ratios. Findings The results showed that slight alternations in the winglet configuration can improve aerodynamic performance for various attack angles. The best lift to drag ratio for the winglet was achieved at a cant angle of 30° and a sweep angle of 65°, which caused a 5.33% increase in the lift to drag ratio. The toe-out angle winglets as compared to the toe-in angles caused the lift to drag ratio to increase because of more attached flow at its surface. The maximum value of the lift to drag ratio was obtained with a toe-out angle (−5°) at an angle of attack 3° which was 2.53% greater than the zero-toed angle winglet. Originality/value This work is relatively unique because the cant, sweep and toe angles were analyzed altogether and led to a significant reduction in drag as compared to wing without winglet. The wing model was compared with the results provided by National Aeronautics and Space Administration so this validated the simulation for different wing-winglet configurations.

Investigation on Aerodynamic Configuration of Monitoring Long Endurance UAV

2014 ◽  
Vol 509 ◽  
pp. 80-85
Author(s):  
Dong Li Ma ◽  
Yu Hang Qiao ◽  
Mu Qing Yang
Keyword(s):  
Design Method ◽  
General Scheme ◽  
Twist Angle ◽  
Weather Condition ◽  
Control Surface ◽  
Induced Drag ◽  
Bad Weather ◽  
Long Endurance ◽  
Drag Ratio ◽  
Aerodynamic Configuration

In recent years, monitoring long endurance UAV is widely used in civil fields such as earthquake relief, it has certain particularities in comparison with conventional UAV; this paper studied and summarized its key technologies in aerodynamic configuration. The research of aerodynamic configuration is based on a general scheme, research indicates that: (1) monitoring long endurance UAV has the characteristics of low-Reynolds number, so laminar airfoil is needed to increase lift-drag ratio; induced drag can be reduced by optimizing wing twist angle; (2) subsection control surface and new design method on flight-quality would improve control reliability and flight quality, which are indispensable for the UAV to guarantee safety in bad weather condition; (3) take-off/landing/taxiing performance should be considered in order to improve the runway adaptability of the UAV.

scholarly journals Computational analysis and design of an aerofoil with morphing tail for improved aerodynamic performance in transonic regime

2022 ◽  
pp. 1-24
Author(s):  
Z.A. Rana ◽  
F. Mauret ◽  
J.M. Sanchez-Gil ◽  
K. Zeng ◽  
Z. Hou ◽  
...  
Keyword(s):  
Computational Analysis ◽  
Structural Integrity ◽  
Aerodynamic Design ◽  
Commercial Aircraft ◽  
Analysis And Design ◽  
Baseline Case ◽  
Shock Location ◽  
Computational Fluid Dynamics Cfd ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Abstract This article focuses on the aerodynamic design of a morphing aerofoil at cruise conditions using computational fluid dynamics (CFD). The morphing aerofoil has been analysed at a Mach number of 0.8 and Reynolds number of $3 \times 10^{6}$ , which represents the transonic cruise speed of a commercial aircraft. In this research, the NACA0012 aerofoil has been identified as the baseline aerofoil where the analysis has been performed under steady conditions at a range of angles of attack between $0^{^{\kern1pt\circ}}$ and $3.86^{^{\kern1pt\circ}}$ . The performance of the baseline case has been compared to the morphing aerofoil for different morphing deflections ( $w_{te}/c = [0.005 - 0.1]$ ) and start of the morphing locations ( $x_{s}/c = [0.65 - 0.80]$ ). Further, the location of the shock wave on the upper surface has also been investigated due to concerns about the structural integrity of the morphing part of the aerofoil. Based upon this investigation, a most favourable morphed geometry has been presented that offers both, a significant increase in the lift-to-drag ratio against its un-morphed counterpart and has a shock location upstream of the start of the morphing part.

Gurney flap scaling for optimum lift-to-drag ratio

AIAA Journal ◽  
1997 ◽  
Vol 35 ◽  
pp. 1888-1890 ◽  
Author(s):  
Philippe Giguere ◽  
Guy Dumas ◽  
Jean Lemay
Keyword(s):  
Gurney Flap ◽  
Drag Ratio ◽  
Lift To Drag Ratio

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.

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