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.

scholarly journals On fluttering modes for aircraft wing model in subsonic air flow

2014 ◽  
Vol 470 (2172) ◽  
pp. 20140582 ◽  
Author(s):  
Marianna A. Shubov
Keyword(s):  
Air Flow ◽  
Spectral Characteristics ◽  
Reduced Model ◽  
Mode Shapes ◽  
Model Parameters ◽  
Aircraft Wing ◽  
Generalized Resolvent ◽  
Wing Model ◽  
The Laplace Transform ◽  
Two Parameter

The paper deals with unstable aeroelastic modes for aircraft wing model in subsonic, incompressible, inviscid air flow. In recent author’s papers asymptotic, spectral and stability analysis of the model has been carried out. The model is governed by a system of two coupled integrodifferential equations and a two-parameter family of boundary conditions modelling action of self-straining actuators. The Laplace transform of the solution is given in terms of the ‘generalized resolvent operator’, which is a meromorphic operator-valued function of the spectral parameter λ, whose poles are called the aeroelastic modes. The residues at these poles are constructed from the corresponding mode shapes. The spectral characteristics of the model are asymptotically close to the ones of a simpler system, which is called the reduced model. For the reduced model, the following result is shown: for each value of subsonic speed, there exists a radius such that all aeroelastic modes located outside the circle of this radius centred at zero are stable. Unstable modes, whose number is always finite, can occur only inside this ‘circle of instability’. Explicit estimate of the ‘instability radius’ in terms of model parameters is given.

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.

Analysis of Drag for an Aircraft Wing Model with and without Winglet

2011 ◽  
Vol 1 (7) ◽  
pp. 89-91
Author(s):  
Mitul Patel ◽  
◽  
Sharvil Shah ◽  
Dharmendra Dubey
Keyword(s):  
Aircraft Wing ◽  
Wing Model
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