A Computational and Experimental Studies of Flexible Wing Aerodynamics

Aono, Hikaru; Kumar, Satish; Wu, Pin; Sällström, Erik; Stanford, Bret; S., Cesnik, Carlos E.; Ifju, Peter; Ukeiley, Lawrence; Shyy, Wei

doi:10.2514/6.2010-554

Cited by 32 publications

(39 citation statements)

References 39 publications

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“…Studies that have attempted to examine this issue in a systematic manner include Refs. [10,[16][17][18][19][20][21][22][23][24][25]. An important finding of Refs.…”

Section: Introductionmentioning

confidence: 99%

Approximate Aerodynamic and Aeroelastic Modeling of Flapping Wings in Hover and Forward Flight

Gogulapati

Friedmann²

2011

52nd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference

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Results generated from an aeroelastic model that combines a nonlinear structural dynamic model based on MARC with an approximate aerodynamic model that incorporates leading edge vortices and a wake model are presented. The aerodynamic model, used in our earlier studies, is extended to forward flight, and the effect of fluid viscosity is incorporated into the formulation in a partial manner. Results presented describe aerodynamic and aeroelastic studies conducted on airfoils and flapping wings in hover and forward flight. For the rigid cases considered, the approximate model shows reasonable agreement with CFD based results and predicts the trends accurately. The aeroelastic results presented indicate that wing flexibility has beneficial effects in both hover and forward flight. Comparisons show that aerodynamic loads are comparable to inertia loads for the cases considered.

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“…Studies that have attempted to examine this issue in a systematic manner include Refs. [10,[16][17][18][19][20][21][22][23][24][25]. An important finding of Refs.…”

Section: Introductionmentioning

confidence: 99%

Approximate Aerodynamic and Aeroelastic Modeling of Flapping Wings in Hover and Forward Flight

Gogulapati

Friedmann²

2011

52nd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference

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“…Insects, such as bees, beetles and dragonflies [24], have stroke amplitudes of about 150˝, presumably for this reason. Most studies to date, investigating flapping wings, use a four-bar linkage flapping mechanisms [14,16,17,45]. Using this type of mechanism makes it technically difficult to achieve amplitudes larger than 90˝.…”

Section: Wing Flapping Frequency and Stroke Amplitude Influencesmentioning

confidence: 99%

“…To obtain a high strength to weight ratio and a high Young's modulus, the frame was often built from carbon or glass composite sheet [13][14][15], aluminum [16] or titanium alloy [17]. The membrane was manufactured from nylon [18], Mylar [18], paper [17], latex [13] or polyester [15].…”

Section: Introductionmentioning

confidence: 99%

“…The highest stall angles of attack, and thus the highest lift coefficients, were achieved by using the most chordwise flexible structures. Aono et al [14] showed that wing flexibility could enhance the aerodynamic forces, using a combination of experimental and computational approaches. In particular, the elastic twisting of the wing was shown to produce substantially larger mean and instantaneous thrust due to shape deformation-induced changes at the effective AOA.…”

Section: Introductionmentioning

confidence: 99%

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The Efficiency of a Hybrid Flapping Wing Structure—A Theoretical Model Experimentally Verified

2016

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To propel a lightweight structure, a hybrid wing structure was designed; the wing's geometry resembled a rotor blade, and its flexibility resembled an insect's flapping wing. The wing was designed to be flexible in twist and spanwise rigid, thus maintaining the aeroelastic advantages of a flexible wing. The use of a relatively "thick" airfoil enabled the achievement of higher strength to weight ratio by increasing the wing's moment of inertia. The optimal design was based on a simplified quasi-steady inviscid mathematical model that approximately resembles the aerodynamic and inertial behavior of the flapping wing. A flapping mechanism that imitates the insects' flapping pattern was designed and manufactured, and a set of experiments for various parameters was performed. The simplified analytical model was updated according to the tests results, compensating for the viscid increase of drag and decrease of lift, that were neglected in the simplified calculations. The propelling efficiency of the hovering wing at various design parameters was calculated using the updated model. It was further validated by testing a smaller wing flapping at a higher frequency. Good and consistent test results were obtained in line with the updated model, yielding a simple, yet accurate tool, for flapping wings design.

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“…Aerodynamic models must be coupled with structural solvers in order to describe the physics of a practical flapping wing. Researchers have coupled both CFD and discrete vortex methods with structural solvers [15,16] that generate results that could be validated against existing experimental data. These computational frameworks also enable the development of new scaling relationships that provide estimates of expected forces from the known parameters of a flapping wing [17].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of the Pressure, Force, and Torque Characteristics of a Rigid Flapping Wing

Yeo

Atkins

Bernal

et al. 2012

50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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Pressure measurements over flapping wings are less commonly available due to the difficulties associated with instrumenting them. This represents an important limitation of the aerodynamic data available for the development of self-contained flapping wing vehicle autopilots and for researchers working on the aerodynamics of bio-inspired flapping wings. This paper describes the design, construction, and testing of a customized flap stand, and a distributed pressure sensing system embedded in a set of rigid flapping wings to provide high speed 'on-board' flow measurements. While the hovering condition is the main focus, the setup is applicable to forward flight conditions as well. Data processing techniques are described along with the method used to measure pressure distributions over the wings. A series of flap tests were conducted in still air, with pressures measured only in air and force and torque measurements taken both in air and in a vacuum. Comparisons between the pressure-based estimates of aerodynamic loads and direct measurements taken by the force instrumentation are presented. The comparisons suggest the pressure-based system provides reasonable estimates of aerodynamic loads but is limited by the frequency response of the pressure lines used. Nomenclature b= wingspan, m m

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A Computational and Experimental Studies of Flexible Wing Aerodynamics

Cited by 32 publications

References 39 publications

Approximate Aerodynamic and Aeroelastic Modeling of Flapping Wings in Hover and Forward Flight

Approximate Aerodynamic and Aeroelastic Modeling of Flapping Wings in Hover and Forward Flight

The Efficiency of a Hybrid Flapping Wing Structure—A Theoretical Model Experimentally Verified

Experimental Investigation of the Pressure, Force, and Torque Characteristics of a Rigid Flapping Wing

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