More Like this

1. Roll Maneuverability of Flapping Flight Winged Systems

   https://doi.org/10.1115/DSCC2020-3309  

   Vejdani, Hamid (October 2020, ASME 2020 Dynamic Systems and Control Conference)

   null (Ed.)

   Abstract The goal of this paper is to study the effect of wing flapping kinematics on roll maneuverability of flapping flight systems. Inspired from birds maneuvering action, we study the effect of asymmetric flapping angular velocities of the wings on generating roll motions on the body. To expand the generality of the results, the equations of motion are written dimensionless. The effect of aerodynamic parameter, forward velocity and wing inertia are presented. The results show that applying asymmetric velocities during flight is useful for relatively larger wings. 

   more » « less
2. Effects of wing pitch kinematics on both aerodynamic and olfactory functions in an upwind surge

   https://doi.org/10.1177/0954406220907950  

   Li, Chengyu (January 2021, Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science)

   Flapping wings of insects serve for both generating aerodynamic forces and enhancing olfactory sensitivities when navigating on the odor-rich planet. Despite the extensive investigations of the aerodynamic function of flapping wings, we have limited understanding of how the flapping wings potentially affect the physiological sensitivities during flight. In this paper, direct numerical simulations were used to investigate a fruit fly model in an upwind surging motion. The wing pitch kinematics were prescribed using a hyperbolic function, which can change the wing pitch profile from a sinusoidal function to a step function by adjusting the “C” factor in the hyperbolic function. Both aerodynamic performance and olfactory detections were quantified at various wing pitch kinematics patterns. The effects of flapping wings on the odor transport were visualized using the Lagrangian approach by uniformly releasing passive odor tracers in upstream. The study revealed that the insect had the potential to achieve higher aerodynamic performance by tailoring wing pitch kinematics, but it could reduce the odor mass flux around the antenna. It was suspected that the natural flyers might sacrifice certain aerodynamic potential to enhance their olfactory sensitivity for surviving purposes. In addition, a trap-and-flick mechanism is proposed here during the supination phase in order to enhance the olfactory sensitivity. Similar to the clip-and-fling mechanism for enhancing the force generation during the pronation phase, the newly proposed trap-and-flick mechanism is also due to the wing-wing interaction in flapping flight. These findings could provide important implications for engineering applications of odor-guided flapping flight. 

   more » « less
3. Role of Active Morphing in the Aerodynamic Performance of Flapping Wings in Formation Flight

   https://doi.org/10.3390/drones5030090  

   Billingsley, Ethan; Ghommem, Mehdi; Vasconcellos, Rui; Abdelkefi, Abdessattar (September 2021, Drones)

   Migratory birds have the ability to save energy during flight by arranging themselves in a V-formation. This arrangement enables an increase in the overall efficiency of the group because the wake vortices shed by each of the birds provide additional lift and thrust to every member. Therefore, the aerodynamic advantages of such a flight arrangement can be exploited in the design process of micro air vehicles. One significant difference when comparing the anatomy of birds to the design of most micro air vehicles is that bird wings are not completely rigid. Birds have the ability to actively morph their wings during the flapping cycle. Given these aspects of avian flight, the objective of this work is to incorporate active bending and torsion into multiple pairs of flapping wings arranged in a V-formation and to investigate their aerodynamic behavior using the unsteady vortex lattice method. To do so, the first two bending and torsional mode shapes of a cantilever beam are considered and the aerodynamic characteristics of morphed wings for a range of V-formation angles, while changing the group size in order to determine the optimal configuration that results in maximum propulsive efficiency, are examined. The aerodynamic simulator incorporating the prescribed morphing is qualitatively verified using experimental data taken from trained kestrel flights. The simulation results demonstrate that coupled bending and twisting of the first mode shape yields the highest propulsive efficiency over a range of formation angles. Furthermore, the optimal configuration in terms of propulsive efficiency is found to be a five-body V-formation incorporating coupled bending and twisting of the first mode at a formation angle of 140 degrees. These results indicate the potential improvement in the aerodynamic performance of the formation flight when introducing active morphing and bioinspiration. 

   more » « less
4. Biomechanics of Insect Flight Stability and Perturbation Response

   https://doi.org/10.1093/icb/icae076  

   Hedrick, Tyson_L; Blandford, Emily; Taha, Haithem_E (June 2024, Integrative And Comparative Biology)

   Synopsis Insects must fly in highly variable natural environments filled with gusts, vortices, and other transient aerodynamic phenomena that challenge flight stability. Furthermore, the aerodynamic forces that support insect flight are produced from rapidly oscillating wings of time-varying orientation and configuration. The instantaneous flight forces produced by these wings are large relative to the average forces supporting body weight. The magnitude of these forces and their time-varying direction add another challenge to flight stability, because even proportionally small asymmetries in timing or magnitude between the left and right wings may be sufficient to produce large changes in body orientation. However, these same large-magnitude oscillating forces also offer an opportunity for unexpected flight stability through nonlinear interactions between body orientation, body oscillation in response to time-varying inertial and aerodynamic forces, and the oscillating wings themselves. Understanding the emergent stability properties of flying insects is a crucial step toward understanding the requirements for evolution of flapping flight and decoding the role of sensory feedback in flight control. Here, we provide a brief review of insect flight stability, with some emphasis on stability effects brought about by oscillating wings, and present some preliminary experimental data probing some aspects of flight stability in free-flying insects. 

   more » « less
5. A Novel Fluid–Structure Interaction Framework for Flapping, Flexible Wings

   https://doi.org/10.1115/1.4044268  

   Schwab, Ryan; Johnson, Erick; Jankauski, Mark (December 2019, Journal of Vibration and Acoustics)

   Fluid–structure interaction (FSI) plays a significant role in the deformation of flapping insect wings. However, many current FSI models are high-order and rely on direct computational methods, thereby limiting parametric studies as well as insights into the physics governing wing dynamics. We develop a novel flapping wing FSI framework that accommodates general wing geometry and fluid loading. We use this framework to study the unilaterally coupled FSI of an idealized hawkmoth forewing considering two fluid models: Reynolds-averaged Navier–Stokes computational fluid dynamics (RANS CFD) and blade element theory (BET). We first compare aerodynamic modal forces estimated by the low-order BET model to those calculated via high fidelity RANS CFD. We find that for realistic flapping kinematics, BET estimates modal forces five orders of magnitude faster than CFD within reasonable accuracy. Over the range flapping kinematics considered, BET and CFD estimated modal forces vary maximally by 350% in magnitude and approximately π/2 radians in phase. The large reduction in computational time offered by BET facilitates high-dimensional parametric design of flapping-wing-based technologies. Next, we compare the contributions of aerodynamic and inertial forces to wing deformation. Under the unilateral coupling assumption, aerodynamic and inertial-elastic forces are on the same order of magnitude—however, inertial-elastic forces primarily excite the wing’s bending mode whereas aerodynamic forces primarily excite the wing’s torsional mode. This suggests that, via conscientious sensor placement and orientation, biological wings may be able to sense independently inertial and aerodynamic forces. 

   more » « less