scholarly journals The hydraulic mechanism in the hind wing veins of Cybister japonicus Sharp (order: Coleoptera)

2016 ◽  
Vol 7 ◽  
pp. 904-913 ◽  
Author(s):  
Jiyu Sun ◽  
Wei Wu ◽  
Mingze Ling ◽  
Bharat Bhushan ◽  
Jin Tong
Keyword(s):  
Hind Wing ◽  
Micro Air Vehicles ◽  
Driving Mechanism ◽  
Hydraulic Control ◽  
Aerodynamic Forces ◽  
Water Beetles ◽  
Diving Beetles ◽  
Hydraulic Mechanism ◽  
Motion Characteristics ◽  
Pressure Changes

The diving beetles (Dytiscidae, Coleoptera) are families of water beetles. When they see light, they fly to the light source directly from the water. Their hind wings are thin and fragile under the protection of their elytra (forewings). When the beetle is at rest the hind wings are folded over the abdomen of the beetle and when in flight they unfold to provide the necessary aerodynamic forces. In this paper, the unfolding process of the hind wing of Cybister japonicus Sharp (order: Coleoptera) was investigated. The motion characteristics of the blood in the veins of the structure system show that the veins have microfluidic control over the hydraulic mechanism of the unfolding process. A model is established, and the hind wing extending process is simulated. The blood flow and pressure changes are discussed. The driving mechanism for hydraulic control of the folding and unfolding actions of beetle hind wings is put forward. This can assist the design of new deployable micro air vehicles and bioinspired deployable systems.

scholarly journals Aerodynamic Detuning Analysis of an Unstalled Supersonic Turbofan Cascade

1986 ◽  
Vol 108 (1) ◽  
pp. 60-67 ◽  
Author(s):  
D. Hoyniak ◽  
S. Fleeter
Keyword(s):  
Flow Field ◽  
Leading Edge ◽  
Rotor Blades ◽  
Driving Mechanism ◽  
Aeroelastic Stability ◽  
Aerodynamic Forces ◽  
Unsteady Aerodynamic ◽  
Influence Coefficients ◽  
Blade Row ◽  
The Stability

A new, and as yet unexplored, approach to passive flutter control is aerodynamic detuning, defined as designed passage-to-passage differences in the unsteady aerodynamic flow field of a rotor blade row. Thus, aerodynamic detuning directly affects the fundamental driving mechanism for flutter, i.e., the unsteady aerodynamic forces and moments acting on individual rotor blades. In this paper, a model to demonstrate the enhanced supersonic unstalled aeroelastic stability associated with aerodynamic detuning is developed. The stability of an aerodynamically detuned cascade operating in a supersonic inlet flow field with a subsonic leading edge locus is analyzed, with the aerodynamic detuning accomplished by means of nonuniform circumferential spacing of adjacent rotor blades. The unsteady aerodynamic forces and moments on the blading are defined in terms of influence coefficients in a manner that permits the stability of both a conventional uniformly spaced rotor configuration as well as the detuned nonuniform circumferentially spaced rotor to be determined. With Verdon’s uniformly spaced Cascade B as a baseline, this analysis is then utilized to demonstrate the potential enhanced aeroelastic stability associated with this particular type of aerodynamic detuning.

scholarly journals AN REHABILITATION ROBOT DRIVEN BY PNEUMATIC ARTIFICIAL MUSCLES

2020 ◽  
Vol 20 (09) ◽  
pp. 2040008 ◽  
Author(s):  
JUN ZHONG ◽  
DONGKAI HE ◽  
CHUN ZHAO ◽  
YUE ZHU ◽  
QIANZHUANG ZHANG
Keyword(s):  
Artificial Muscles ◽  
Driving Mechanism ◽  
Rehabilitation Robot ◽  
Pneumatic Muscle ◽  
Rehabilitation Robots ◽  
Ankle Rehabilitation ◽  
Human Ankle ◽  
Movement Ability ◽  
Motion Characteristics ◽  
Muscle Actuators

Rehabilitation robots are playing an important role in restoring movement ability of hemiplegic patients. However, most of these robots adopt motors as actuators. Considering human body is a flexible organism, rigid motors lack compliance when getting in touch with patients. This paper designs an ankle rehabilitation robot by employing pneumatic muscle actuators which are soft and have similar compliance with biological muscles. Analysis of motion characteristics of human ankle is performed, and relationship between angle and torque of human ankle acquired from experiment is studied. Driving mechanism using pneumatic muscle actuators is addressed carefully and ankle-rehabilitation robot is designed. Then, dynamics of the robot is established and structure optimization of the driving mechanism is performed. Consequently, prototype is manufactured and assembled.

Design of a Bio-Inspired Spherical Four-Bar Mechanism for Flapping-Wing Micro Air-Vehicle Applications

2008 ◽  
Author(s):  
Matt McDonald ◽  
Sunil K. Agrawal
Keyword(s):  
Three Dimensional ◽  
Micro Air Vehicles ◽  
Aerodynamic Performance ◽  
Flapping Wing ◽  
Micro Air Vehicle ◽  
Aerodynamic Forces ◽  
Flapping Motion ◽  
Wing Motion ◽  
Air Vehicle ◽  
Flapping Mechanism

Design of flapping-wing micro air-vehicles presents many engineering challenges. As observed by biologists, insects and birds exhibit complex three-dimensional wing motions. It is believed that these unique patterns of wing motion create favorable aerodynamic forces that enable these species to fly forward, hover, and execute complex motions. From the perspective of micro air-vehicle applications, extremely lightweight designs that accomplish these motions of the wing, using just a single, or a few actuators, are preferable. This paper presents a method to design a spherical four-bar flapping mechanism that approximates a given spatial flapping motion of a wing, considered to have favorable aerodynamics. A spherical flapping mechanism was then constructed and its aerodynamic performance was compared to the original spatially moving wing using an instrumented robotic flapper with force sensors.

Numerical Simulation of Influences of the Body’s Presence on Flow Around the Wings in Insect Flapping Flight

2019 ◽  
Author(s):  
Kohei Yamauchi ◽  
Tomohiro Fukui ◽  
Koji Morinishi
Keyword(s):  
Lift Coefficient ◽  
Computational Simulation ◽  
Micro Air Vehicles ◽  
Fruit Fly ◽  
Flapping Flight ◽  
Vortical Flow ◽  
Aerodynamic Forces ◽  
Body Model ◽  
Root Region ◽  
Boltzmann Method

Abstract In this research, we numerically investigated the influences of the body’s presence on flow around the hovering fruit fly with regularized lattice Boltzmann method. In recent years, insect’s flapping flight system has been investigated because their superior flight mechanisms are expected to improve the flight abilities of micro air vehicles. Because of the simplification of experimental equipment and computational simulation, the insect model without body is often used to investigate the flow around the hovering flight insect. However, the gap between the wing and body can significantly change the flow around the wing root. Thus, we conducted investigations of the influences of the body’s presence on the vortical flow structure and cycle-averaged lift coefficient. As a result, the aerodynamic forces on the wings were enhanced by the body’s presence. The flow at the gap between wing and body enhanced the vortex strength and aerodynamic forces on the wing root region. Also, the cycle-averaged lift coefficient of the with body model was slightly higher than that of the without body model. If the wing’s flapping motion or the shape of the wing is changed, the effects of the body’s presence will cause different flow around the wing root. Therefore, it is necessary to take body’s presence into consideration.

scholarly journals Phasing of dragonfly wings can improve aerodynamic efficiency by removing swirl

2008 ◽  
Vol 5 (28) ◽  
pp. 1303-1307 ◽  
Author(s):  
James R Usherwood ◽  
Fritz-Olaf Lehmann
Keyword(s):  
Mechanical Model ◽  
Hind Wing ◽  
Micro Air Vehicles ◽  
Flapping Flight ◽  
Single Pair ◽  
Helicopter Rotors ◽  
Aerodynamic Efficiency ◽  
Winged Form ◽  
Low Speed ◽  
Dragonfly Wings

Dragonflies are dramatic, successful aerial predators, notable for their flight agility and endurance. Further, they are highly capable of low-speed, hovering and even backwards flight. While insects have repeatedly modified or reduced one pair of wings, or mechanically coupled their fore and hind wings, dragonflies and damselflies have maintained their distinctive, independently controllable, four-winged form for over 300 Myr. Despite efforts at understanding the implications of flapping flight with two pairs of wings, previous studies have generally painted a rather disappointing picture: interaction between fore and hind wings reduces the lift compared with two pairs of wings operating in isolation. Here, we demonstrate with a mechanical model dragonfly that, despite presenting no advantage in terms of lift, flying with two pairs of wings can be highly effective at improving aerodynamic efficiency. This is achieved by recovering energy from the wake wasted as swirl in a manner analogous to coaxial contra-rotating helicopter rotors. With the appropriate fore–hind wing phasing, aerodynamic power requirements can be reduced up to 22 per cent compared with a single pair of wings, indicating one advantage of four-winged flying that may apply to both dragonflies and, in the future, biomimetic micro air vehicles.

scholarly journals Direct Numerical Simulations on the three-dimensional wake transition of flows over NACA0012 airfoil at Re = 1000

2021 ◽  
Vol 13 ◽  
pp. 175682932110556
Author(s):  
Taiba Kouser ◽  
Yongliang Xiong ◽  
Dan Yang ◽  
Sai Peng
Keyword(s):  
Aerodynamic Force ◽  
Angle Of Attack ◽  
Three Dimensional ◽  
Micro Air Vehicles ◽  
Reynold Number ◽  
Angle Of Incidence ◽  
Aerodynamic Forces ◽  
Vortex Pattern ◽  
Naca0012 Airfoil ◽  
Wake Modes

For micro air vehicles (MAV), the precise prediction of aerodynamic force plays an important role. The aerodynamic force of a comparative low Reynold number (Re) vehicle tends to be affected by the different flow modes. In this paper, the aerodynamic performance of a three-dimensional NACA0012 airfoil is studied numerically. A range of angles of attack ( α) 0°−25° and Reynolds number 1000 is considered. Mean and fluctuating coefficients of aerodynamic forces around NACA0012 airfoil are analyzed for different wake modes. The difference of aerodynamic forces between two and three-dimensional simulations are compared. The results show that the wake remains steady two-dimensional for lower angles of attack. At α = 9°, Von Karman vortex pattern is noticed. Flow transition to three-dimensional as the angle of attack increases from α = 13°. 3D wake is found to be stable with parallel shedding mode for 14°-17°. However, these modes become finer with the gradual increase in angle of incidence. While, wake loses its three-dimensional stability to chaotic with gradual increment in angle of attack afterwards.

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