Unsteady Aerodynamics of Deformable Thin Airfoils

Walker, William P.; Patil, Mayuresh

doi:10.2514/1.c031434

Cited by 19 publications

(4 citation statements)

References 14 publications

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“…This method can also be applied to morphing airfoils [124]. In addition, there are some other aerodynamic theories that take into account the flexibility of the wing [125,126]. For example, Johnson et al [125] summarized the systematic application of von Kármán and Sears' extended unsteady thin airfoil theory to general morphing airfoils.…”

Section: Unsteady Flow Field Solution Technologymentioning

confidence: 99%

Recent Progress on Aeroelasticity of High-Performance Morphing UAVs

Lv¹,

Zha²,

Zeng³

et al. 2022

Computer Modeling in Engineering &Amp; Sciences

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The high-performance morphing aircraft has become a research focus all over the world. The morphing aircraft, unlike regular unmanned aerial vehicles (UAVs), has more complicated aerodynamic characteristics, making itmore difficultto conduct its design, model analysis, and experimentation. This paper reviews the recent process and the current status of aeroelastic issues, numerical simulations, and wind tunnel test of morphing aircrafts. The evaluation of aerodynamic characteristics, mechanism, and relevant unsteady dynamic aerodynamic modeling throughout the morphing process are the primary technological bottlenecks formorphing aircrafts. The unstable aerodynamic forces have a significant impact on the aircraft handling characteristics, control law design, and flight safety. In the past, the structural analysis of morphing aircrafts, flight dynamics modeling, computational mesh morphing technology, and aerodynamic calculation were performed in promoting the development of next generation UAVs, with nonlinear dynamic challenges includingtransonic aeroelastic problems and high angle of attack aeroelastic problems. At present, many facets of these difficulties, together with the accompanying numerical simulation studies, remain under-explored. In addition, wind tunnel experiments face significant challenges in the dynamic morphing process. Finally, dynamic unsteady aerodynamic characteristics in the continuous morphing process still need to be verified by more related experiments.

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Section: Unsteady Flow Field Solution Technologymentioning

confidence: 99%

Recent Progress on Aeroelasticity of High-Performance Morphing UAVs

Lv¹,

Zha²,

Zeng³

et al. 2022

Computer Modeling in Engineering &Amp; Sciences

View full text Add to dashboard Cite

show abstract

“…For distributed flexibility with a low mass ratio, Floryan and Rowley used the Chebyshev numerical method to elucidate the propulsive performance and the optimal distribution of flexibility of the passively flexible foil and revealed that thrust increment will accompany power consumption when the stiffness is large (Floryan & Rowley 2020). While the Chebyshev series method seems the standard method to determine the deformation of the foil and the fluid flow through the collocation procedure (Walker & Patil 2014;Moore 2017), it has obviously simplified the direct two-dimensional fluid solver, which makes rapid searching of all possible material distributions possible. However, the numerical solution from the Chebyshev series method makes the correlation between the performance of the foil and the physical parameters still less clear, which calls for the development of closed-form theory to this flow-structure interaction.…”

Section: Introductionmentioning

confidence: 99%

Analytical results for pitching kinematics and propulsion performance of flexible foil

Du,

2024

J. Fluid Mech.

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Natural flyers and swimmers employ flexible wings or fins to propel. While the complex interaction between the foil with deformation and the surrounding non-steady fluid environment defines the propulsion performance of the propellers, elucidating the interaction mechanism through theoretical models earns much challenge. Based on elastokinetics and linear potential flow theory, this study proposes a simplified analytical model to clarify the kinematics and the propulsion performance of a flexible thin foil pitching in flow. The dynamical forces, including the inertial force of the foil and the non-steady fluid pressure, are used to determine the averaged deformation angle of the foil. Combining the averaged deformation angle and the prescribed driving pitching motion, the kinematics of the foil is resolved analytically. Based on the analytical expressions for the corresponding pitching motion, analytical relations among the physical parameters of the stiffness and the mass of the foil and the driving frequency are given to these critical conditions, including resonance of the flow–structure system, equal pitching amplitude between the flexible foil and the rigid counterpart, phase angle transition from ${\rm \pi}/2$ to $- {\rm \pi}/2$ . Subsequently, the performance of the foil, including the thrust, the power and the propulsive efficiency, as a function of the flexibility of the foil are derived, together with the introduction of a bluff body type offset drag to the thrust. The formulated analytical theory, which matches nicely with previous reports, will help to interpret the effect of the flexibility and regulate the propulsive performance of the flexible foil when pitching in fluid.

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“…Based on an S-shaped aircraft airfoil, Reid and Kozak (2006) studied the change of the maximum lift-to-drag ratio and the separation bubble position of the airfoil at different Reynolds numbers by changing the airfoil shape design parameters. Based on the potential flow theory, Walker and Patil (2014) created a kind of harmonic deformation thin airfoil similar to the S-shaped inverted arch airfoil. By changing the parameters in the theoretical model, the aerodynamic and aeroelastic characteristics of the harmonic thin airfoil were optimized.…”

Section: Introductionmentioning

confidence: 99%

The airfoil design and parameter optimization of the deformable micro air vehicle

Huang,

Qiu,

Wang

2023

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PurposeSince most of the existing literature do not disclose the node coordinate data of its fixed-wing aircraft airfoil, in order to develop and obtain a practical and suitable deformation airfoil for fixed-wing micro air vehicle (MAV), this paper proposes an improved airfoil design method of fixed-wing MAV based on the profile data of S5010 airfoil.Design/methodology/approachCombined with the body shape variation of the stingray in the propulsion process, the parametric study of the aerodynamic shape of the original design airfoil is carried out to explore the influence of a single parameter change on the aerodynamic performance of the airfoil. Then, according to the influence law of single parameter variation on the aerodynamic performance of the airfoil, the original airfoil is synthetically deformed by changing multiple parameters.FindingsBy comparing the aerodynamic performance of the multi-parameter deformed airfoil with the original airfoil, it is found that the lift coefficient of the multi-parameter deformed airfoil changes from negative to positive value when AOA = 0°. When AOA = 2°, the lift coefficient growth rate is the largest, which is 47.27%, and the lift-to-drag ratio is increased by 50.00%. At other angles of attack, the lift, drag, and torque coefficients of the multi-parameter deformed airfoil are optimized to some extent.Originality/valueCombined the body shape variation of the stingray in the propulsion process, the parametric study of the aerodynamic shape of the original design airfoil is carried out to explore the influence of a single parameter change on the aerodynamic performance of the airfoil.

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Unsteady Aerodynamics of Deformable Thin Airfoils

Cited by 19 publications

References 14 publications

Recent Progress on Aeroelasticity of High-Performance Morphing UAVs

Recent Progress on Aeroelasticity of High-Performance Morphing UAVs

Analytical results for pitching kinematics and propulsion performance of flexible foil

The airfoil design and parameter optimization of the deformable micro air vehicle

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