scholarly journals Kinematic Optimization of a Flexible Wing Undergoing Flapping and Pitching

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Yue Wu ◽  
Changchuan Xie ◽  
Yang Meng ◽  
Chao Yang
Keyword(s):  
Aspect Ratio ◽  
Optimization Algorithm ◽  
Flapping Wing ◽  
Flapping Flight ◽  
Propulsive Efficiency ◽  
Flexible Wing ◽  
Passive Deformation ◽  
Kinematic Optimization ◽  
Rigid Wing ◽  
Computational Aeroelasticity

In recent years, there has been widespread interest in the design of microair vehicles (MAVs) for flapping flight with high-aspect ratio wings due to their high efficiency and energy savings. However, the flexibility of a flapping wing causes the aeroelastic effect, which remains a subject of investigation. Generally, existing research simulates active bending and twisting of flexible wings under the assumption of neglecting flapping inertia. In this research, the kinematic optimization of a bionic wing with passive deformation in forward flight while undergoing flapping and pitching is considered. To this end, a computational aeroelasticity framework, which includes the three-dimensional unsteady vortex lattice method (UVLM) and the Newmark-β method, is constructed for flapping flight. Under the assumption of linear elastic deformation, this tool is capable of simulating attached flows over a thin wing and capturing unsteady effects of wakes. A bionic numerical wing with an aspect ratio of 6.5, chord Reynolds number of 1.9 × 105, and reduced frequency less than 0.1 is investigated in kinematic optimization. The computational aeroelasticity framework is combined with a global optimization algorithm to identify the optimal kinematics that maximize the propulsive efficiency under the minimum average lift constraint. Two types of numerical wings, rigid wing and flexible wing, are considered here to compare the influence of deformation on the aerodynamics of the flapping wing. The results show that the aeroelastic effect, which increases the flapping amplitude, yields a significant improvement in terms of propulsive efficiency. In addition, the optimization algorithm maximizes the thrust efficiency while satisfying the required lift. Moreover, the optimal kinematics of both the rigid wing and the flexible wing reach the maximum flapping angle, which indicates that a larger range of motions is needed for optimal kinetics when loosening the boundary conditions.

scholarly journals Functionally Graded Flexural Rigidity Improves Flight Performance in Flapping Wing Insects

2021 ◽  
Author(s):  
Joseph Reade ◽  
Mark Jankauski
Keyword(s):  
Power Consumption ◽  
Flexural Rigidity ◽  
Aerodynamic Force ◽  
Flapping Wing ◽  
Functionally Graded ◽  
Muscle Size ◽  
Lattice Method ◽  
Flexible Wing ◽  
Wide Range ◽  
Rigid Wing

AbstractInsect wings are highly heterogeneous structures, with flexural rigidity varying one to two orders of magnitude over the wing surface. This heterogeneity influences the deformation the flapping wing experiences under aerodynamic and inertial loads. However, it is not well understood how this flexural rigidity gradient affects wing performance. Here, we develop a reduced-order model of the flapping wing using the assumed mode method and unsteady vortex lattice method to model the structural and fluid dynamics, respectively. We conduct parameter studies to explore how variable flexural rigidity affects mean lift production, power consumption and the forces required to flap the wing. We find that there is an optimal flexural rigidity distribution that maximizes lift production; this distribution generally corresponds to a 3:1 ratio between the wing’s flapping and natural frequencies, though the precise ratio is sensitive to flapping kinematics. For hovering flapping kinematics, the optimized flexible wing produces 20% more lift and requires 15% less power compared to a rigid wing but needs 20% higher forces to flap. Even when flapping kinematics deviate from those observed during hover, the flexible wing outperforms the rigid wing in terms of aerodynamic force generation and power across a wide range of flexural rigidity gradients. Peak force requirements and power consumption are inversely proportional with respect to flexural rigidity gradient, which presents a trade-off between insect muscle size and energy storage requirements. The model developed in this work can be used to efficiently investigate other spatially variant morphological or material wing features moving forward.

scholarly journals Dove: A biomimetic flapping-wing micro air vehicle

2017 ◽  
Vol 10 (1) ◽  
pp. 70-84 ◽  
Author(s):  
Wenqing Yang ◽  
Liguang Wang ◽  
Bifeng Song
Keyword(s):  
Mechanism Design ◽  
Flapping Wing ◽  
Micro Air Vehicle ◽  
Flexible Wing ◽  
The Past ◽  
Ground Station ◽  
Air Vehicle ◽  
Research Goal ◽  
Color Video ◽  
Flapping Mechanism

This paper describes the design and development of the Dove, a flapping-wing micro air vehicle (FWMAV), which was developed in Northwestern Polytechnical University. FWMAVs have attracted international attentions since the past two decades. Since some achievements have been obtained, such as the capability of supporting an air vehicle to fly, our research goal was to design an FWMAV that has the ability to accomplish a task. Main investigations were presented in this paper, including the flexible wing design, the flapping mechanism design, and the on-board avionics development. The current Dove has a mass of 220 g, a wingspan of 50 cm, and the ability of operating fully autonomously, flying lasts half an hour, and transmitting live stabilized color video to a ground station over 4 km away.

scholarly journals Experimental Study of Rigid and Flexible Tandem Wing for Micro Aerial Vehicle

2021 ◽  
Vol 85 (2) ◽  
pp. 33-43
Author(s):  
Wan Mazlina Wan Mohamed ◽  
Mohd Azmi Ismail ◽  
Muhammad Ridzwan Ramli ◽  
Aliff Farhan Mohd Yamin ◽  
Koay Mei Hyie ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Unmanned Aerial Vehicle ◽  
Lift Coefficient ◽  
Reynolds Numbers ◽  
Micro Aerial Vehicle ◽  
Flexible Wing ◽  
Vehicle Structure ◽  
Aerial Vehicle ◽  
Wing Skin ◽  
Rigid Wing

Unmanned aerial vehicle is becoming increasingly popular each year. Now, aeronautical researchers are focusing on size minimization of unmanned aerial vehicle, especially drone and micro aerial vehicle. The lift coefficient of micro aerial vehicle has wing dimension of 12 cm and mass of less than 7 g. In the present study, with the aid of 3D printer, polylactic acid material was used to develop the micro aerial vehicle structure for tandem wing arrangement. The materials for rigid wing skin and flexible wing skin were laminating film and latex membrane, respectively. The present work elaborates the lift coefficient profiles on rigid wing skin and flexible wing skin at wing flapping frequency of 11 Hz, three different Reynolds numbers of 14000, 19000 and 24000, and five different angles of attacks between 0° and 50°. According to the results obtained, the lift coefficient decreased as the Reynolds number increased. The lift coefficient increased up to 9 as the angle of attack increased from 0° to 50° at the Reynolds number of 14000 for flexible wing skin. The results also showed that the lift coefficient of flexible wing skin was higher than that of rigid wing skin at the attack angle of10° and below, except for the Reynolds number of 14000.

Induced Strain Actuation for Solid-State Ornithopters: An Aeroelastic Study

2018 ◽  
Author(s):  
Francis Hauris ◽  
Onur Bilgen
Keyword(s):  
Reynolds Number ◽  
Solid State ◽  
Aspect Ratio ◽  
Interaction Model ◽  
Flapping Wing ◽  
Flapping Wings ◽  
Structural Behavior ◽  
Structure Interaction ◽  
Dynamic Motion ◽  
Lift And Drag

This paper investigates the dynamic aeroelastic behavior of strain actuated flapping wings with various geometries and boundary conditions. A fluid-structure interaction model of a plate-like flapping wing is developed. Assuming a chord Reynolds number of 100,000, the wing is harmonically actuated while varying parameters such as aspect ratio and wing root clamped percentage. Characteristic metrics for the dynamic motion, natural frequency, lift and drag are developed. These results are compared with purely structural behavior to understand the aeroelastic effects.

Wing-Wake Interaction of Insect-Like Flapping Wing in Hover: Effect of Aspect Ratio and Kinematics at Re~104

2019 ◽  
Author(s):  
Reynolds Addo-Akoto ◽  
Jong-Seob Han ◽  
Jae-Hung Han
Keyword(s):  
Aspect Ratio ◽  
Time Course ◽  
Aerodynamic Force ◽  
Flapping Wing ◽  
Windward Side ◽  
Water Tank ◽  
Image Velocimetry ◽  
Wake Interaction ◽  
Entire Flow ◽  
Accelerated Flow

Abstract In this paper, the effect of wing aspect ratio and kinematics on wing-wake interaction at Re∼104, which matched the flight regime of flapping-wing micro air vehicle (FWMAV), was investigated. The dynamically scaled-up robotic model submerged in a water tank environment revealed that the wing-wake interaction augmented lift across a decrease in both aspect ratio and wing pitching duration. At such high Re, a time-course digital particle image velocimetry (DPIV) measurement showed the entire flow was strongly dominated by trailing-edge vortices (TEV). A pair of counter-rotating TEV was found to induce a jetlike flow towards the windward side of the wing at stroke reversal. The transfer of momentum from the accelerated flow to the wing caused the enhanced lift. The size of the pair vortex decreased for an increase in both aspect ratio and wing pitching duration. The size of the TEV pair was the key feature found to generate the observed aerodynamic force characteristics.

scholarly journals Three-dimensional scaling laws of cetacean propulsion characterize the hydrodynamic interplay of flukes' shape and kinematics

2020 ◽  
Vol 17 (163) ◽  
pp. 20190655 ◽  
Author(s):  
Fatma Ayancik ◽  
Frank E. Fish ◽  
Keith W. Moored
Keyword(s):  
Aspect Ratio ◽  
Scaling Laws ◽  
Three Dimensional ◽  
Force Production ◽  
Numerical Data ◽  
Added Mass ◽  
Cetacean Species ◽  
Propulsive Efficiency ◽  
Fluid Environment ◽  
Pitch Ratio

Cetaceans convert dorsoventral body oscillations into forward velocity with a complex interplay between their morphological and kinematic features and the fluid environment. However, it is unknown to what extent morpho-kinematic features of cetaceans are intertwined to maximize their efficiency. By interchanging the shape and kinematic variables of five cetacean species, the interplay of their flukes morpho-kinematic features is examined by characterizing their thrust, power and propulsive efficiency. It is determined that the shape and kinematics of the flukes have considerable influence on force production and power consumption. Three-dimensional heaving and pitching scaling laws are developed by considering both added mass and circulatory-based forces, which are shown to closely model the numerical data. Using the scaling relations as a guide, it is determined that the added mass forces are important in predicting the trend between the efficiency and aspect ratio, however, the thrust and power are driven predominately by the circulatory forces. The scaling laws also reveal that there is an optimal dimensionless heave-to-pitch ratio h * that maximizes the efficiency. Moreover, the optimal h * varies with the aspect ratio, the amplitude-to-chord ratio and the Lighthill number. This indicates that the shape and kinematics of propulsors are intertwined, that is, there are specific kinematics that are tailored to the shape of a propulsor in order to maximize its propulsive efficiency.

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