Lift and Drag of Flapping Membrane Wings at High Angles of Attack

Zakaria, Mohamed Y.; Allen, D. W.; Woolsey, Craig A.; Hajj, Muhammad R.

doi:10.2514/6.2016-3554

Cited by 13 publications

(13 citation statements)

References 12 publications

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“…Open Sci. 8: 210452 different flapping wing vehicle configurations, including design tools for concepts developed for forward [42,43] and hovering [44] flight modes. Recent progress in miniaturization of engineering systems together with the desire to create tiny aerial robots have motivated the development of a range of flapping wing vehicle concepts at insect-scale.…”

Section: Discussionmentioning

confidence: 99%

“…The development of flapping wing vehicles requires generic toolsets that would allow conceptual design/sizing of such vehicles while taking into consideration the correct interaction between the different subsystems in a transparent fashion. Design methods have been previously presented for different flapping wing vehicle configurations, including design tools for concepts developed for forward [ 42 , 43 ] and hovering [ 44 ] flight modes. Recent progress in miniaturization of engineering systems together with the desire to create tiny aerial robots have motivated the development of a range of flapping wing vehicle concepts at insect-scale.…”

Section: Discussionmentioning

confidence: 99%

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Scalability of resonant motor-driven flapping wing propulsion systems

Nabawy

Marcinkeviciute

2021

R. Soc. open sci.

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This work aims to develop an integrated conceptual design process to assess the scalability and performance of propulsion systems of resonant motor-driven flapping wing vehicles. The developed process allows designers to explore the interaction between electrical, mechanical and aerodynamic domains in a single transparent design environment. Wings are modelled based on a quasi-steady treatment that evaluates aerodynamics from geometry and kinematic information. System mechanics is modelled as a damped second-order dynamic system operating at resonance with nonlinear aerodynamic damping. Motors are modelled using standard equations that relate operational parameters and AC voltage input. Design scaling laws are developed using available data based on current levels of technology. The design method provides insights into the effects of changing core design variables such as the actuator size, actuator mass fraction and pitching kinematics on the overall design solution. It is shown that system efficiency achieves peak values of 30–36% at motor masses of 0.5–1 g when a constant angle of attack kinematics is employed. While sinusoidal angle of attack kinematics demands more aerodynamic and electric powers compared with the constant angle of attack case, sinusoidal angle of attack kinematics can lead to a maximum difference of around 15% in peak system efficiency.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Scalability of resonant motor-driven flapping wing propulsion systems

Nabawy

Marcinkeviciute

2021

R. Soc. open sci.

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“…. (5) Instantaneous variations of the differences in the force coefficients for all the five wing planforms are shown in Fig. 9(a) and (b).…”

Section: Variation In Instantaneous Force Coefficients Over a Gust Cyclementioning

confidence: 99%

“…Fluid dynamics of flapping wings in various modes of flight viz. hover (4) and forward flight (5) have been studied. Apart from assessing the flow physics of single wing, studies have also been reported on tandem wings with different inter-wing positions (6) and relative kinematics (7) .…”

Section: Introductionmentioning

confidence: 99%

Simulation of flapping wings subjected to gusty inflow

Mathur

Vengadesan

2019

Aeronaut. j.

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Ornithopters and entomopters should be insensitive to the gusty environment during outdoor operations. Hence, it becomes imperative to understand their behaviour under the influence of gust for ensuring stable flight. In light of this, the present numerical study focused on understanding the aerodynamics of flapping wings with five different planform shapes under the influence of a spatiotemporally varying frontal gust. 3D, unsteady, laminar, and incompressible Navier-Stokes equations were solved using finite volume formulation. A canonical case of asymmetric 1 degree of freedom (DoF) flapping kinematics was considered. Horizontal and vertical force patterns in constant and gusty inflow conditions were numerically computed and compared. Findings were analyzed quantitatively by comparing the differences in the instantaneous force patterns, ordinal scoring approach, and phase space plots. Qualitative comparisons were made based on plots of vortex structures and surface pressure contours for constant and gusty inflow conditions for wings with different planform shapes. Spanwise Lagrangian Coherent Structures (LCS) of all the five wings were also compared. Studies revealed that the elliptical wing exhibited low sensitivity and inverse semi-elliptical wing exhibited high sensitivity to the gusty inflow. Rectangular, triangular and semi-elliptical shaped wings were moderately sensitive to the gusty inflow. This finding, within the limitations of the flapping kinematics and simulation conditions considered for the present study, supported the fact that many natural flyers like forest raptors, non-migratory passerines, pheasants, and partridges have adopted elliptical wing planform for efficient flight.

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“…Zakaria et al (2015) showed that the inclusion of intertial power requirements is essential for physical and proper optimization [6]. They further studied the aerodynamic forces generated in forward flight for different Reynolds numbers and flapping frequency [7]. Whitney (2012) designed and developed one of the tiniest FWMAVs [8].…”

Section: Introductionmentioning

confidence: 99%

Thrust Enhancement and Degradation Mechanisms due to Self-Induced Vibrations in Bio-inspired Flying Robots

Deb¹,

Huang²,

Verma³

et al. 2023

Preprint

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Bio-inspired flying robot (BIFR) which flies by flapping their wings experience continuously oscillating aerodynamic forces. These oscillations in the driving force cause vibrations in the motion of the body around the mean trajectory. That is, a BIFR hovering in place is not exactly stationary in space, rather it is oscillating in almost all directions about the hovering point in space. These oscillations affect the aerodynamic performance of the flier. Assessing the effect of these oscillations on particularly thrust generation in two-wings and four-wings BIFRs is the main objective of this work. To achieve such a goal two experimental setups were considered to measure the average thrust for the two BIFRs. The average thrust is measured over the flapping cycle of the BIFR. In the first experimental setup, the BIFR is installed at the end of a pendulum rod, in place of the pendulum mass. While flapping, the model creates a thrust force which raises the model along the circular trajectory of the pendulum mass to a certain angular position, which is an equilibrium point and it is also stable. Measuring the weight of the BIFR and the equilibrium angle it obtains, it is straightforward to estimate the average thrust by moment balance about the pendulum hinge. This pendulum setup allows the BIFR model to freely oscillate back and forth along the circular trajectory about the equilibrium position. As such, the estimated average thrust includes the effects of these self-induced vibrations. In contrast, we use another setup that relies on a load cell to measure thrust where the model is completely fixed. The thrust measurement of both the BIFRs using the above mentioned setups exhibited an interesting trend. The load cell or the fixed test lead to a higher thrust than the pendulum or the oscillatory test for the two-wings model, showing an opposite behavior for the four-wings model. That is self induced vibration have different effects on the two BIFR models. Note that the aerodynamic mechanisms of thrust generation for two-wings and four-wings are fundamentally different. A two-wings BIFR generates thrust through traditional flapping mechanisms whereas a four-wings model enjoys clapping effect and wing-wing interaction. In the present work, we use motion capture system, aerodynamic modeling and flow visualization to study the underlying physics of the observed different behaviors of the two flapping models.

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Lift and Drag of Flapping Membrane Wings at High Angles of Attack

Cited by 13 publications

References 12 publications

Scalability of resonant motor-driven flapping wing propulsion systems

Scalability of resonant motor-driven flapping wing propulsion systems

Simulation of flapping wings subjected to gusty inflow

Thrust Enhancement and Degradation Mechanisms due to Self-Induced Vibrations in Bio-inspired Flying Robots

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