Aerodynamic modelling of insect-like flapping flight for micro air vehicles

Ansari, Salman A.; Żbikowski, Rafał; Knowles, K.

doi:10.1016/j.paerosci.2006.07.001

Cited by 250 publications

(148 citation statements)

References 122 publications

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“…New models to estimate the aerodynamic forces can be generated and, also, existing models can be improved. Many such models exist since the pioneering work of Wagner [1925] and Theodorsen [1949], among others, and they have been recently reviewed by Ansari et al [2006] and Taha et al [2012]. For small amplitude motions at high Re there is a complete theory based on potential flow that predicts the aerodynamic forces produced on a thin airfoil [Wagner, 1925, Theodorsen, 1949.…”

Section: Introductionmentioning

confidence: 99%

On the aerodynamic forces on heaving and pitching airfoils at low Reynolds number

2017

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The influence that the kinematics of pitching and heaving 2D airfoils have on the aerodynamic forces is investigated using Direct Numerical Simulations and a force decomposition algorithm. Large amplitude motions are considered (of the order of one chord), with moderate Reynolds numbers and reduced frequencies of order O(1), varying the mean pitch angle and the phase shift between the pitching and heaving motions. Our results show that the surface vorticity contribution (viscous effects) to the aerodynamic force is negligible compared to the contributions from the body motion (fluid inertia) and the vorticity within the flow (circulation). For the range of parameters considered here, the latter tends to be instantaneously oriented in the direction normal to the chord of the airfoil. Based on the results discussed in the paper, a reduced order model for the instantaneous aerodynamic force is proposed, taking advantage of the force decomposition and the chord-normal orientation of the contribution from vorticity within the flow to the total aerodynamic force. The predictions of the proposed model are compared to those of a similar model from the literature, showing a noticeable improvement on the prediction of the mean thrust, and a smaller improvement on the prediction of mean lift and the instantaneous force coefficients.

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Section: Introductionmentioning

confidence: 99%

On the aerodynamic forces on heaving and pitching airfoils at low Reynolds number

2017

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“…The Kutta condition is generally enforced at the trailing edge by these unsteady models. However, as pointed out by Ansari et al [2006], during stroke reversals the fluid is more likely to flow around the trailing edge rather than along it such that the applicability of the Kutta condition in the conventional sense is questionable.…”

Section: Introductionmentioning

confidence: 99%

A predictive quasi-steady model of aerodynamic loads on flapping wings

Goosen

Keulen

2016

J. Fluid Mech.

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Quasi-steady aerodynamic models play an important role in evaluating aerodynamic performance and conducting design and optimization of flapping wings. The kinematics of flapping wings is generally a resultant motion of wing translation (yaw) and rotation (pitch and roll). Most quasisteady models are aimed at predicting the lift and thrust generation of flapping wings with prescribed kinematics. Nevertheless, it is insufficient to limit flapping wings to prescribed kinematics only since passive pitching motion is widely observed in natural flapping flights and preferred for the wing design of flapping wing micro air vehicles (FWMAVs). In addition to the aerodynamic forces, an accurate estimation of the aerodynamic torque about the pitching axis is required to study the passive pitching motion of flapping flights. The unsteadiness arising from the wing's rotation complicates the estimation of the centre of pressure (CP) and the aerodynamic torque within the context of quasisteady analysis. Although there are a few attempts in literature to model the torque analytically, the involved problems are still not completely solved. In this work, we present an analytical quasi-steady model by including four aerodynamic loading terms. The loads result from the wing's translation, rotation, their coupling as well as the added-mass effect. The necessity of including all the four terms in a quasi-steady model in order to predict both the aerodynamic force and torque is demonstrated. Validations indicate a good accuracy of predicting the CP, the aerodynamic loads and the passive pitching motion for various Reynolds numbers. Moreover, compared to the existing quasi-steady models, the presented model does not rely on any empirical parameters and, thus, is more predictive, which enables application to the shape and kinematics optimization of flapping wings.

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“…The flapping amplitude determines the travel distance of chordwise section of wing planform, and thus the vortex dynamical evolutionary process. While high flapping frequency means high frequency evolution of highly unsteady flow field, namely, the starting vortex, LEV, trailing edge vortex, wing tip vortex, downwash vortex and wake vortex are interwoven and interact at different instants thus influence the aerodynamic performance of wing planform [62,67]. As mentioned above, lower flapping frequency and appropriate flapping amplitude is expected for the designer to successfully solve the engineering problem of Bio-FWMAV although simultaneously compromising high maneuverability yielded by high lift from unsteady mechanism.…”

Section: Sensitivity Analysis For Combined Optimal Wgp and Wkpmentioning

confidence: 99%

Wing Geometry and Kinematic Parameters Optimization of Flapping Wing Hovering Flight

Zhang

2016

Applied Sciences

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How to efficiently mimic the wing shape and kinematics pattern of an able hovering living flier is always a concern of researchers from the flapping wing micro aerial vehicles community. In this work, the separate or combined optimizations of wing geometry or/and wing kinematic parameters are systematically performed to minimize the energy of hovering flight, firstly on the basis of analytically extended quasi-steady aerodynamic model by using hybrid genetic algorithm. Before the elaboration of the optimization problem, the parametrization description of dynamically scaled wing with non-dimensional conformal feature of insect-scale rigid wing is firstly proposed. The optimization results show that the combined optimization of wing geometry and kinematic parameters can obtain lower flapping frequency, larger wing geometry parameters and lower power density in comparison with those from other cases of optimization. Moreover, the flapping angle for the optimization involving wing kinematic parameters manifests harmonic shape profile and the pitch angle possesses round trapezoidal profile with certain faster time scale of pitch reversal. The combined optimization framework provides a novel method for the conceptual design of fundamental parameters of biomimetic flapping wing micro aerial vehicle.

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Aerodynamic modelling of insect-like flapping flight for micro air vehicles

Cited by 250 publications

References 122 publications

On the aerodynamic forces on heaving and pitching airfoils at low Reynolds number

On the aerodynamic forces on heaving and pitching airfoils at low Reynolds number

A predictive quasi-steady model of aerodynamic loads on flapping wings

Wing Geometry and Kinematic Parameters Optimization of Flapping Wing Hovering Flight

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