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

Gogulapati, Abhijit; Friedmann, Peretz P.

doi:10.2514/6.2011-2008

Cited by 25 publications

(38 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…28 demonstrates that the effect of the aerodynamic forces is small when compared to the case in which only the inertial forces are present. This is not a general finding: as discussed in References [13,14] the relative importance of aerodynamic and inertia loads in flapping wings is a configuration-dependent property. Fig.…”

Section: Effect Of Inhomogeneity Of the Density Properties In The Prementioning

confidence: 85%

See 1 more Smart Citation

Effect of Structural Anisotropy and Geometric Nonlinearity on Forward Flapping Wing Flight

Demasi

Gordnier

2013

54th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

View full text Add to dashboard Cite

Flapping flight is commonly used in nature at low Reynolds numbers. This work investigates the physical aspects of forward flight for flapping unmanned aerial systems. The kinematics discussed in this work is based on an anticlockwise eight-shaped flapping cycle. First the complex aerodynamic structures and their evolution (leading edge and trailing edge vortices) are presented. Then, the typical mechanisms for generating the lift and thrust are discussed with emphasis on the unsteadiness of the flow features during both the downstroke and upstroke phases.The inhomogeneity of the wing in terms of mass distribution is studied for the rigid case and it is shown that a higher density at the wing root is beneficial in respect to the mechanical power required to achieve the forward flight.The assumption of rigid wing is then removed and the elastic deformation and its effects are investigated. The relative importance of inertial/aerodynamic effects is assessed with the inclusion of structural geometric nonlinearities.

show abstract

Section: Effect Of Inhomogeneity Of the Density Properties In The Prementioning

confidence: 85%

“…The other two contributions are P aero = M aero •ω (see equation 13) and P in = M in •ω (see equation 17 and the final expression reported in equation 18). Equation 19 is then rewritten as…”

Section: Planar Rigid Wing: Power Calculationmentioning

confidence: 98%

Effect of Structural Anisotropy and Geometric Nonlinearity on Forward Flapping Wing Flight

Demasi

Gordnier

2013

54th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

View full text Add to dashboard Cite

show abstract

“…The aeroelastic model 11,12 is obtained by coupling a nonlinear finite element model of the wing with an approximate aerodynamic model that incorporates LEV's and a free wake. The ingredients of the model are concisely described next.…”

Section: Nonlinear Aeroelastic Modelmentioning

confidence: 99%

Optimization of the Kinematics of a Flapping Wing MAV in Hover for Enhanced Performance

Gogulapati

Friedmann

Martins

2013

54th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

Self Cite

View full text Add to dashboard Cite

The kinematics of a rigid and flexible flapping wing micro air vehicle (MAV) in hover are optimized for enhanced performance using surrogate based approximation of the unsteady aerodynamic loads. The surrogates are generated using kriging interpolation of the time averaged thrust generated and power consumed by the wings. The fitting data is obtained using a nonlinear approximate aeroelastic model that combines a nonlinear finite element based structural dynamic model with an approximate unsteady aerodynamic model. The parameter space for the rigid wings consists of seven kinematic parameters. For the flexible wing case, six structural parameters are used to augment the kinematic parameters, resulting in a total of 13 design variables. The surrogates are combined with a hybrid search algorithm to identify feasible designs that produce the desired combination of thrust and power. The best rigid and flexible configurations predicted using the surrogates are superior to the best designs available in the corresponding sets of sample points used to create the surrogates. Thrust and power are found to be competing design objectives. The phase angle between flap and pitch motions has a significant impact on the wing performance for fixed stroke amplitudes and frequency. The peak performance of flexible wings occurs for smaller amounts of pitch actuation compared to the rigid wings due to elastic wing twist. Rigid wings performed better than flexible wings in several regions of the parameter space, leading to the conclusion that the choice between rigid or flexible wings is not straightforward.

show abstract

“…The seminal works done by Ellington [1]- [3], Dickinson [4] and Wang [5], [6] have greatly contributed to the understanding of the aerodynamic mechanisms of insect flight. Gogulapati and Friedmann [7], Aono et al [8], Kang et al [9] have deepened the knowledge in fluid-structure interactions in flapping flight. In parallel, other important work from Ansari et al [10], [11], Bolender [12], Orlowsky et al [13], [14] focused on flight kinematics and contributed to the creation of extended wing beat and full body flight kinematic and dynamic models.…”

Section: Introductionmentioning

confidence: 97%

Tethered vs. free flight force determination of the DelFly II Flapping Wing Micro Air Vehicle

Caetano

Perçin

Visser

et al. 2014

2014 International Conference on Unmanned Aircraft Systems (ICUAS)

View full text Add to dashboard Cite

The determination of dynamic forces acting on a Flapping Wing Micro Aerial Vehicle (FWMAV) is a challenging task due to the unsteady nature of force generation mechanisms. To assure a proper force identification in future researches, this work compares two different methods to obtain the longitudinal forces acting on FWMAVs and discusses their applicability regions. The methods were 1) calculation of forces from the recordings of the FWMAV's position in a free flight condition; 2) direct force measurements in a tethered flight condition in a wind tunnel. The DelFly II is used as the FWMAV test platform in the measurements. During free flight experiments, its position and attitude were recorded at a rate of 200Hz using an external visual tracking system, whose acquired information was then analyzed to obtain the flight states and calculate the forces and moments that act on the platform during flight, under a set of kinematic assumptions. Subsequently, similar flight conditions were tested in the tethered situation. An ATI Nano-17 Titanium force transducer was used to measure time-resolved forces. The results for the most common flight regime of the DelFly, which is a slow forward flight at a high body pitch angle, are presented. It is shown that the tethered force balance tests agree with the free flight data when assessing the aerodynamic forces that are perpendicular to the stroke plane of the flapping wing. However, the forces that act along the stroke plane are coupled with structural dynamic terms, thus affecting the final lift and thrust identification. These results point to inadequate force identification in fixed point force measurements, due to effect the of the dynamic modes of the FWMAV body, thus advising proper cross-comparing between experimental methods.

show abstract

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

Cited by 25 publications

References 33 publications

Effect of Structural Anisotropy and Geometric Nonlinearity on Forward Flapping Wing Flight

Effect of Structural Anisotropy and Geometric Nonlinearity on Forward Flapping Wing Flight

Optimization of the Kinematics of a Flapping Wing MAV in Hover for Enhanced Performance

Tethered vs. free flight force determination of the DelFly II Flapping Wing Micro Air Vehicle

Contact Info

Product

Resources

About