Effects of Flapping Wing Angle of Attack on Lift and Thrust

2009 ◽  
Author(s):  
Yutong Wang ◽  
Shankar Kalyanasundaram ◽  
John Young
Keyword(s):  
Angle Of Attack ◽  
Flapping Wing

scholarly journals Scaling of the performance of insect-inspired passive-pitching flapping wings

2019 ◽  
Vol 16 (161) ◽  
pp. 20190609 ◽  
Author(s):  
Kit Sum Wu ◽  
Jerome Nowak ◽  
Kenneth S. Breuer
Keyword(s):  
Scaling Laws ◽  
Aerodynamic Force ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Flapping Wing ◽  
Dimensionless Parameters ◽  
Linear Elastic ◽  
Simple Implementation ◽  
Pitch Regulation ◽  
Cauchy Number

Flapping flight using passive pitch regulation is a commonly used mode of thrust and lift generation in insects and has been widely emulated in flying vehicles because it allows for simple implementation of the complex kinematics associated with flapping wing systems. Although robotic flight employing passive pitching to regulate angle of attack has been previously demonstrated, there does not exist a comprehensive understanding of the effectiveness of this mode of aerodynamic force generation, nor a method to accurately predict its performance over a range of relevant scales. Here, we present such scaling laws, incorporating aerodynamic, inertial and structural elements of the flapping-wing system, validating the theoretical considerations using a mechanical model which is tested for a linear elastic hinge and near-sinusoidal stroke kinematics over a range of scales, hinge stiffnesses and flapping frequencies. We find that suitably defined dimensionless parameters, including the Reynolds number, Re , the Cauchy number, Ch , and a newly defined ‘inertial-elastic’ number, IE, can reliably predict the kinematic and aerodynamic performance of the system. Our results also reveal a consistent dependency of pitching kinematics on these dimensionless parameters, providing a connection between lift coefficient and kinematic features such as angle of attack and wing rotation.

The leading-edge vortex and aerodynamics of insect-based flapping-wing micro air vehicles

2009 ◽  
Vol 113 (1142) ◽  
pp. 253-262 ◽  
Author(s):  
P. C. Wilkins ◽  
K. Knowles
Keyword(s):  
Entire Range ◽  
Angle Of Attack ◽  
Leading Edge ◽  
Micro Air Vehicles ◽  
Reynolds Numbers ◽  
Flapping Wing ◽  
Computational Method ◽  
Leading Edge Vortex ◽  
Air Vehicle ◽  
Edge Vortex

AbstractThe aerodynamics of insect-like flapping are dominated by the production of a large, stable, and lift-enhancing leading-edge vortex (LEV) above the wing. In this paper the phenomenology behind the LEV is explored, the reasons for its stability are investigated, and the effects on the LEV of changing Reynolds number or angle-of-attack are studied. A predominantly-computational method has been used, validated against both existing and new experimental data. It is concluded that the LEV is stable over the entire range of Reynolds numbers investigated here and that changes in angle-of-attack do not affect the LEV’s stability. The primary motivation of the current work is to ascertain whether insect-like flapping can be successfully ‘scaled up’ to produce a flapping-wing micro air vehicle (FMAV) and the results presented here suggest that this should be the case.

An Investigation on the Lift Mechanism of Flapping-Wing Air Vehicle

2014 ◽  
Vol 971-973 ◽  
pp. 353-358 ◽  
Author(s):  
Feng Bao ◽  
Jin Wen Yang ◽  
Qi Yang ◽  
Xiang Xiang Fu
Keyword(s):  
Particle Image ◽  
Angle Of Attack ◽  
Reynolds Numbers ◽  
Flapping Wing ◽  
Stream Velocity ◽  
Low Reynolds Numbers ◽  
Image Velocimetry ◽  
Air Vehicle ◽  
Lift Mechanism ◽  
The Difference

This paper deals with the aerodynamical problems of rigid flapping wing at low Reynolds numbers with emphasis on investigating the lift generation mechanism of simplified ornithopter. Theoretical analysis and Particle Image Velocimetry (PIV) were conducted to analyze and verify the lift generation conditions. The results revealed that the rigid flapping wing will generate lift under the conditions of both angle of attack α and free incoming flow velocity v were not zero. With the wings flapped periodically, there were votexes formed, developed and shedding alternately. The calculation of curl demonstrated that the greater of flapping speed, the greater of curl. The statistic of circulation suggested that the circulation generation of flapping down was greater than that of flapping up, the circulation difference contributed to the lift generation. The difference of circulation will increase along with the angle of attack α in the circumstances of free stream velocity v and flapping speed π and flapping amplitude Φ matched well.

scholarly journals Flight Performance Estimation of Bionic Flapping-Wing Micro Air Vehicle

2018 ◽  
Vol 36 (4) ◽  
pp. 636-643
Author(s):  
Wenqing Yang ◽  
Bifeng Song ◽  
Guanglin Gao
Keyword(s):  
High Speed ◽  
Angle Of Attack ◽  
Estimation Method ◽  
Flapping Wing ◽  
Micro Air Vehicle ◽  
Performance Estimation ◽  
Estimation Methods ◽  
Flight Performance ◽  
Air Vehicle ◽  
Performance Calculation

Bionic flapping-wing micro air vehicle(MAV) has received worldwide attention.The flight performance calculation is an important step in the conceptual design.The differences in performance estimation methods between the flapping-wing and conventional fixed-wing aircraft are analyzed.Based on the results of the aerodynamic estimation and wind tunnel experimental measurement, the flight performance estimation method of flapping-wing micro air vehicle is proposed, and the performance of level flight, climbing, and duration are calculated and analyzed.The frequency represents the accelerator in a certain extent, while the frequency is coupled with lift and thrust.The results show that there may be two stable cruising states at certain frequencies, one is the small angle of attack with high speed, the other is the small speed with big angle of attack, and the two states have different power consumption.According to the parameters of the vehicle, climbing performance and duration performance can be obtained.The speed versus power characteristic curve is a U shape, minimum slope of the U curve can be obtained through the mapping method to calculate the farthest flight speed, and the minimum velocity of U-shaped curve is the speed for longest duration.The proposed flight performance calculation method can be used to evaluate the flight capability of bionic micro flapping-wing air vehicle.

Design, Lift Prediction and Test of a PZT Drive Mechanism of a New Concept of Micro Flapping Wing Rotor

2012 ◽  
Vol 490-495 ◽  
pp. 2081-2085 ◽  
Author(s):  
Jing Lu ◽  
Ning Jun Fan
Keyword(s):  
Experimental Data ◽  
Parametric Study ◽  
Angle Of Attack ◽  
Aerodynamic Characteristics ◽  
Flapping Wing ◽  
Experimental Results ◽  
Rotary Motion ◽  
Initial Angle ◽  
Drive Mechanism ◽  
Piezoelectric Drive

To reduce the complexity involved in achieving the intricate motion and hence complexity mechanism, a new concept of Micro Flapping wing Rotor is firstly proposed to achieve active flapping and passive rotary motion. Secondly, aerodynamic analysis is made to understand schematic principles of this MFWR. Thirdly, parametric study (flapping amplitude, flapping frequency and initial angle of attack) using Theodorsen’s theory for lift prediction makes a significantly role for aerodynamic characteristics. At last, the prototype of a piezoelectric drive mechanism is designed and tested to compare the experimental data with theoretical values. The comparison shows that the lift prediction is closer to the experimental results.

scholarly journals Scalability of resonant motor-driven flapping wing propulsion systems

2021 ◽  
Vol 8 (9) ◽  
pp. 210452
Author(s):  
Mostafa R. A. Nabawy ◽  
Ruta Marcinkeviciute
Keyword(s):  
Scaling Laws ◽  
Design Method ◽  
Angle Of Attack ◽  
Flapping Wing ◽  
Design Solution ◽  
System Efficiency ◽  
Operational Parameters ◽  
Design Environment ◽  
Propulsion Systems ◽  
Constant Angle

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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