The Validation of a Generalized Aerodynamic Model for a Multi-Body Bio-Inspired Wing

2013 ◽  
Author(s):  
Christopher J. Blower ◽  
Adam M. Wickenheiser
Keyword(s):  
Air Flow ◽  
Lower Surface ◽  
Airfoil Surface ◽  
Number Range ◽  
Aircraft Wings ◽  
Wing Model ◽  
Constant Strength ◽  
Hinge Points ◽  
Wing Morphing ◽  
Multi Body

Bio-inspiration has introduced new and innovative flow control methods in gust alleviation, maneuverability and stability improvement for morphing aircraft wings. The bio-inspired wing model under consideration imitates the techniques used by birds to manipulate localized air flow through the installation of feather-like panels across the airfoil’s upper and lower surface, replacing the traditional wing’s surface and trailing edge flap. Each flap is designed to rotate into both the airfoil profile and inbound air flow, using a single degree of freedom about their individual hinge points located at 20%, 40%, 60% and 80% of the chord. This wing morphing technique offers flap configurations typically unattainable by traditional aircraft and enables some advantageous maneuvers, including reduced turning radii and aero-braking. Due to the number of potential configurations, a generalized adaptive panel method (APM) has been developed to model the pressure distribution using a series of constant-strength doublets along the airfoil surface. To accommodate for the wake regions generated by the unconventional wing profiles, viscous Computational Fluid Dynamics (CFD) simulations are performed to characterize these regions and identify their outer boundaries. The wake profile geometries are integrated into the APM, and are used to accurately model the aerodynamic influence of the wake. To calculate the drag generated by each configuration, Thwaites’ laminar and Head’s turbulent boundary layer methods are implemented to enable identification of flow transition and separation along the airfoil surface. The integration of these aerodynamic techniques allows the flight characteristics, including the pressure, friction, lift, drag, and moment coefficients, of each morphing airfoil configuration to be calculated. The computed aerodynamic coefficients are validated using experimental data from a 4′×1′×1′ test section in a low speed suction wind tunnel operating over a Reynolds Number range of 150,000–450,000.

scholarly journals Numerical Investigation of Aeroelastic Mode Distribution for Aircraft Wing Model in Subsonic Air Flow

2010 ◽  
Vol 2010 ◽  
pp. 1-23 ◽  
Author(s):  
Marianna A. Shubov ◽  
Stephen Wineberg ◽  
Robert Holt
Keyword(s):  
Boundary Value Problem ◽  
Numerical Investigation ◽  
Air Flow ◽  
Affirmative Answer ◽  
Positive Answer ◽  
Aircraft Wing ◽  
Aircraft Wings ◽  
Flutter Speed ◽  
Wing Model ◽  
Analytical Formulas

In this paper, the numerical results on two problems originated in aircraft wing modeling have been presented.The first problemis concerned with the approximation to the set of the aeroelastic modes, which are the eigenvalues of a certain boundary-value problem. The affirmative answer is given to the following question: can the leading asymptotical terms in the analytical formulas be used as reasonably accurate description of the aeroelastic modes? The positive answer means that these leading terms can be used by engineers for practical calculations.The second problemis concerned with the flutter phenomena in aircraft wings in a subsonic, incompressible, inviscid air flow. It has been shown numerically that there exists a pair of the aeroelastic modes whose behavior depends on a speed of an air flow. Namely, when the speed increases, the distance between the modes tends to zero, and at some speed that can be treated as the flutter speed these two modes merge into one double mode.

scholarly journals Fuzzy uncertainty analysis and reliability assessment of aeroelastic aircraft wings

2020 ◽  
Vol 124 (1275) ◽  
pp. 786-811
Author(s):  
M. Rezaei ◽  
S.A. Fazelzadeh ◽  
A. Mazidi ◽  
M.I. Friswell ◽  
H.H. Khodaparast
Keyword(s):  
Structural Parameters ◽  
Low Cost ◽  
Fuzzy Variable ◽  
Fuzzy Uncertainty ◽  
Aircraft Wings ◽  
Wing Flutter ◽  
Flutter Speed ◽  
Wing Model ◽  
Safe Region ◽  
Air Speed

ABSTRACTIn the present study, fuzzy uncertainty and reliability analysis of aeroelastic aircraft wings are investigated. The uncertain air speed and structural parameters are represented by fuzzy triangular membership functions. These uncertainties are propagated through the wing model using a fuzzy interval approach, and the uncertain flutter speed is obtained as a fuzzy variable. Further, the reliability of the wing flutter is based on the interference area in the pyramid shape defined by the fuzzy flutter speed and air speed. The ratio between the safe region volume and the total volume of the pyramid gives the reliability value. Two different examples are considered—a typical wing section, and a clean wing—and the results are given for various wind speed conditions. The results show that the approach considered is a low-cost but suitable method to estimate the reliability of the wing flutter speed in the presence of uncertainties.

Numerical Investigation of the Ground Effect for a Small Bird

2013 ◽  
Vol 29 (3) ◽  
pp. 433-441 ◽  
Author(s):  
J.-H. Tang ◽  
J.-Y. Su ◽  
C.-H. Wang ◽  
J.-T. Yang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Investigation ◽  
Ground Effect ◽  
Lower Surface ◽  
Experimental Models ◽  
Simplified Model ◽  
Wing Model ◽  
Aerodynamic Effect ◽  
Small Bird

AbstractAn investigation with computational fluid dynamics of the ground effect on a small bird revealed quantitatively the obstruction of the vortex expansion resulting from the presence of the ground at varied distance. Preceding authors focused mainly on the bird's wings, generally neglecting the bird's body; we discuss specifically the distinction of the aerodynamic effect between cases with and without the presence of the bird's body. The results of simulation show that, considering only two wings, for a distance between the wing model and the ground smaller than a semi-span, the smaller is the ground clearance, the more significant is the ground effect. At clearance 0.37 times a semi-span, the drag is decreased 11%, and the lift is increased 5.6%. The ground effect for an intact bird model composed of both wings and body is less effective than that for a simplified model with body omitted, because a suction was observed on the lower surface of the intact bird's trunk at clearance 0.37 times a semi-span; for this reason the intact bird model benefits less from the ground effect than the model with body excluded, but increased lift and decreased drag remain observable. This research treating the ground effect on a gliding bird reveals the importance of the presence of the bird's body in both computational and experimental models.

Use of Multiple SMA Wires for Morphing of Inflatable Wings

2010 ◽  
Author(s):  
Anthony D. McDonald ◽  
Scott J. I. Walker
Keyword(s):  
Flight Control ◽  
Control Method ◽  
Control Surface ◽  
Static Testing ◽  
Wing Model ◽  
Additional Control ◽  
Pulling Force ◽  
Wing Morphing ◽  
The University ◽  
Control Surfaces

The concept of inflatable wings has design heritage and they have recently seen renewed interest, largely due to the increased demand in unmanned aerial vehicles (UAVs). They offer design advantages over conventional wings, particularly with regard to stowage and portability, since they can be tightly packed when undeployed. Unfortunately current methods of flight control involve the use of additional control surfaces attached to the trailing edge of the wing, adversely affecting the stowage capabilities. One way of overcoming this restriction is to use the wing itself as a control surface, by morphing the very shape of the wing to achieve the desired results. This article outlines the research performed at the University of Southampton into differing configurations of Shape Memory Alloy (SMA) wires as a controllable actuator for the wing morphing. Specifically the use of multiple wires to further enhance this control was the focus of this work. A simple test rig was constructed in order to evaluate the pulling force achievable by combinations of SMA wires in a number of configurations. The most promising of these configurations was then attached to an inflatable wing model for further testing. Both static testing and wind tunnel testing was undertaken, evaluating the authority of flight control such a system could achieve. The test results are presented in this paper, giving an initial performance assessment of the proposed control method.

scholarly journals Quantifying the dynamic wing morphing of hovering hummingbird

2017 ◽  
Vol 4 (9) ◽  
pp. 170307 ◽  
Author(s):  
Masateru Maeda ◽  
Toshiyuki Nakata ◽  
Ikuo Kitamura ◽  
Hiroto Tanaka ◽  
Hao Liu
Keyword(s):  
High Speed ◽  
Wrist Joint ◽  
Three Dimensional ◽  
Angle Of Incidence ◽  
Right Wing ◽  
Wing Model ◽  
Upward Direction ◽  
The Right ◽  
Wing Morphing ◽  
Stroke Cycle

Animal wings are lightweight and flexible; hence, during flapping flight their shapes change. It has been known that such dynamic wing morphing reduces aerodynamic cost in insects, but the consequences in vertebrate flyers, particularly birds, are not well understood. We have developed a method to reconstruct a three-dimensional wing model of a bird from the wing outline and the feather shafts (rachides). The morphological and kinematic parameters can be obtained using the wing model, and the numerical or mechanical simulations may also be carried out. To test the effectiveness of the method, we recorded the hovering flight of a hummingbird ( Amazilia amazilia ) using high-speed cameras and reconstructed the right wing. The wing shape varied substantially within a stroke cycle. Specifically, the maximum and minimum wing areas differed by 18%, presumably due to feather sliding; the wing was bent near the wrist joint, towards the upward direction and opposite to the stroke direction; positive upward camber and the ‘washout’ twist (monotonic decrease in the angle of incidence from the proximal to distal wing) were observed during both half-strokes; the spanwise distribution of the twist was uniform during downstroke, but an abrupt increase near the wrist joint was found during upstroke.

A Three Dimensional Iterative Panel Method for Bio-Inspired Multi-Body Wings

2014 ◽  
Author(s):  
Akash Dhruv ◽  
Christopher J. Blower ◽  
Adam M. Wickenheiser
Keyword(s):  
Three Dimensional ◽  
Panel Method ◽  
Preliminary Design ◽  
Turbulent Environments ◽  
Pressure Distributions ◽  
Constant Strength ◽  
Aerial Vehicle ◽  
Experimental Values ◽  
Multi Body ◽  
Surface Loads

The continuing growth of Unmanned Aerial Vehicle (UAV) use in reconnaissance and surveillance has led to an increased demand for novel flight systems that improve vehicle flight capabilities in cluttered and turbulent environments. Bio-inspired wings with feather-like flaps have been proposed to enable bird-scale UAVs to fly robustly in such environments. This paper presents the development of a three-dimensional iterative constant strength doublet Adaptive Panel Method (APM) for calculating the flight characteristics of a multi-body wing operating in any of its possible configurations. A three-dimensional wake relaxation algorithm is incorporated into the model, which enables accurate wake shapes and down-stream roll-up for each flap configuration to be derived. Wake modeling is shown to improve the accuracy of the pressure distributions induced by the wake-body interactions. The flight coefficients calculated using this method are validated by experimental values obtained from a low speed suction wind tunnel operating at a Reynolds number of 300,000. Finally, it is shown that the APM aids in determining accurate surface loads for the preliminary design process of multi-body wings.

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