scholarly journals Gliding in the Amazonian canopy: adaptive evolution of flight in Morpho butterflies

2021 ◽  
Author(s):  
Camille Le Roy ◽  
Dario Amadori ◽  
Samuel Charberet ◽  
Jaap Windt ◽  
Florian T. Muijres ◽  
...  
Keyword(s):  
Adaptive Evolution ◽  
High Speed ◽  
Wing Shape ◽  
Flight Behavior ◽  
Aerodynamic Efficiency ◽  
Aerodynamic Properties ◽  
Open Canopy ◽  
Morphometric Analyses ◽  
Forest Strata ◽  
Aerodynamic Modelling

The diversity of flying animals suggests that countless combinations of morphologies and behaviors have evolved with specific lifestyles, thereby exploiting diverse aerodynamic mechanisms. Elucidating how morphology, flight behavior and aerodynamic properties together diversify with contrasted ecologies remains however seldom accomplished. Here, we studied the adaptive co-divergence in wing shape, flight behavior and aerodynamic efficiency among Morpho butterflies living in different forest strata, by combining high-speed videography in the field with morphometric analyses and aerodynamic modelling. By comparing canopy and understory species, we show that adaptation to an open canopy environment resulted in increased glide efficiency. Moreover, this enhanced glide efficiency was achieved by different canopy species through strikingly distinct combinations of flight behavior, wing shape and aerodynamic mechanisms, highlighting the multiple pathways of adaptive evolution.

scholarly journals Automatic tracking of free-flying insects using a cable-driven robot

2020 ◽  
Vol 5 (43) ◽  
pp. eabb2890 ◽  
Author(s):  
Rémi Pannequin ◽  
Mélanie Jouaiti ◽  
Mohamed Boutayeb ◽  
Philippe Lucas ◽  
Dominique Martinez
Keyword(s):  
High Speed ◽  
Vision System ◽  
Tracking Error ◽  
Parallel Robot ◽  
Flight Behavior ◽  
Agrotis Ipsilon ◽  
Natural Environments ◽  
Free Flight ◽  
Flying Insects ◽  
Online Tracking

Flying insects have evolved to develop efficient strategies to navigate in natural environments. Yet, studying them experimentally is difficult because of their small size and high speed of motion. Consequently, previous studies were limited to tethered flights, hovering flights, or restricted flights within confined laboratory chambers. Here, we report the development of a cable-driven parallel robot, named lab-on-cables, for tracking and interacting with a free-flying insect. In this approach, cameras are mounted on cables, so as to move automatically with the insect. We designed a reactive controller that minimizes the online tracking error between the position of the flying insect, provided by an embedded stereo-vision system, and the position of the moving lab, computed from the cable lengths. We validated the lab-on-cables with Agrotis ipsilon moths (ca. 2 centimeters long) flying freely up to 3 meters per second. We further demonstrated, using prerecorded trajectories, the possibility to track other insects such as fruit flies or mosquitoes. The lab-on-cables is relevant to free-flight studies and may be used in combination with stimulus delivery to assess sensory modulation of flight behavior (e.g., pheromone-controlled anemotaxis in moths).

Study of Airscrews for High Speed Aeroplanes

1940 ◽  
Vol 44 (352) ◽  
pp. 322-337
Author(s):  
Lucio Lazzarino
Keyword(s):  
Special Reference ◽  
Present Article ◽  
High Speed ◽  
Numerical Evaluation ◽  
Experimental Results ◽  
Aerodynamic Efficiency ◽  
Angular Velocities ◽  
Mach Numbers ◽  
High Mach

RésuméIt is demonstrated how, with increase in speed, the diameter of optimum efficiency and the maximum possible value of efficiency of an airscrew diminish. The efficiency of a system of two counter-revolving airscrews with different angular velocities is then determined, and the variation of efficiency with variation in the relation between the angular velocities of the two airscrews.With increase in the height and speed of flight, airscrew performance inevitably falls off, frequently in a marked degree; this being mainly due to the decrease in aerodynamic efficiency of the blade sections at high Mach numbers.The object of the present article is to analyse the influence exerted upon the performance of an airscrew by the various parameters that determine it, wit-h special reference to those connected with the speed and height of flight.A similar study has also been made of systems constituted of two counter-rotating airscrews, with a view to comparing them with isolated airscrews designed to absorb the same power under identical conditions.By the methods here described, an approximate numerical evaluation of the performance can be made, utilising the experimental results which are already to hand.

scholarly journals The influence of flight style on the aerodynamic properties of avian wings as fixed lifting surfaces

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2495 ◽  
Author(s):  
John J. Lees ◽  
Grigorios Dimitriadis ◽  
Robert L. Nudds
Keyword(s):  
Aerodynamic Drag ◽  
Bird Species ◽  
Reynolds Numbers ◽  
Wing Shape ◽  
Minimum Drag ◽  
Quantitative Studies ◽  
Aerodynamic Properties ◽  
Primary Driver ◽  
Morphological Differences ◽  
Lifting Surfaces

The diversity of wing morphologies in birds reflects their variety of flight styles and the associated aerodynamic and inertial requirements. Although the aerodynamics underlying wing morphology can be informed by aeronautical research, important differences exist between planes and birds. In particular, birds operate at lower, transitional Reynolds numbers than do most aircraft. To date, few quantitative studies have investigated the aerodynamic performance of avian wings as fixed lifting surfaces and none have focused upon the differences between wings from different flight style groups. Dried wings from 10 bird species representing three distinct flight style groups were mounted on a force/torque sensor within a wind tunnel in order to test the hypothesis that wing morphologies associated with different flight styles exhibit different aerodynamic properties. Morphological differences manifested primarily as differences in drag rather than lift. Maximum lift coefficients did not differ between groups, whereas minimum drag coefficients were lowest in undulating flyers (Corvids). The lift to drag ratios were lower than in conventional aerofoils and data from free-flying soaring species; particularly in high frequency, flapping flyers (Anseriformes), which do not rely heavily on glide performance. The results illustrate important aerodynamic differences between the wings of different flight style groups that cannot be explained solely by simple wing-shape measures. Taken at face value, the results also suggest that wing-shape is linked principally to changes in aerodynamic drag, but, of course, it is aerodynamics during flapping and not gliding that is likely to be the primary driver.

Aerodynamically Alleviated Marine Vehicle (AAMV): Bridging the Maritime-to-Air Domain

2015 ◽  
Author(s):  
Daniel James ◽  
Maurizio Collu
Keyword(s):  
High Speed ◽  
High Performance ◽  
Ground Effect ◽  
Full Potential ◽  
Conceptual Approach ◽  
Aerodynamic Properties ◽  
Improved Performance ◽  
Lifting Surfaces ◽  
The Stability ◽  
Marine Vehicle

As high performance marine vessels with improved performance characteristics are being requested by governments (DARPA 2015) and commercial operators, the Aerodynamically Alleviated Marine Vehicle (AAMV) provides a solution that combines speeds typical of rotary-wing and light fixed-wing aircraft with payload and loitering ability found in current high speed craft. The innovative AAMV hybrid aero-marine platform utilizes an alternative implementation of wing-in-ground effect (WIG), a proven technology with a fascinating history of high speed marine operation. This paper outlines some challenges and the work completed towards the development of a hybrid class of vessel that is able to bridge the maritime-to-air domain, comfortably operating in the water surface yet still delivering the speed of aircraft during an airborne cruise phase. An overview of current WIG design is briefly presented, leading to the conceptual approach for the AAMV. Development and assessment of the aerodynamic properties of the lifting surfaces are shown, with analysis of several wing profiles and their effect on the total lift force, drag force, and pitching moment that directly influence the stability characteristics of the vehicle. A methodology for sizing an appropriate platform is summarized, along with experimental results of a high speed hullform with characteristics suitable for this intended application. Finally, particulars of a potential AAMV are derived using an iterative numerical method and briefly compared to current craft. For close to a century, the influence of ground effect has promised economy for low-skimming flight over smooth water (Raymond 1921), a promise that has yet to reach its full potential.

Effects of stretch receptor ablation on the optomotor control of lift in the hawkmothManduca sexta

2001 ◽  
Vol 204 (21) ◽  
pp. 3683-3691 ◽  
Author(s):  
Mark A. Frye
Keyword(s):  
Action Potentials ◽  
High Speed ◽  
Visual Cues ◽  
Aerodynamic Force ◽  
Video Recording ◽  
Force Production ◽  
Stretch Receptor ◽  
Flight Behavior ◽  
Wing Kinematics ◽  
Control Flight

SUMMARYIn insects, fast sensory feedback from specialized mechanoreceptors is integrated with guidance cues descending from the visual system to control flight behavior. A proprioceptive sensory organ found in both locusts and moths, the wing hinge stretch receptor, has been extensively studied in locusts for its powerful influence on the activity of flight muscle motoneurons and interneurons. The stretch receptor fires a high-frequency burst of action potentials near the top of each wingstroke and encodes kinematic variables such as amplitude and timing. Here, I describe the effects of stretch receptor ablation on the visual control of lift during flight in the hawkmoth Manduca sexta. Using a combination of extracellular muscle recordings, force and position measurements and high-speed video recording, I tracked power muscle activity, net vertical flight force (lift), abdomen deflection and wing kinematics in response to image motions of varying velocity during tethered flight in a wind tunnel. As a result of bilateral ablation of the wing hinge stretch receptors, visually evoked lift decreased to nearly one-third of that exhibited by intact animals. The phase and frequency of indirect power muscle action potentials and the patterns of abdominal deflection were unaffected; however, wingstroke amplitude was clearly reduced after ablation. Collectively, these results suggest that stretch receptor feedback is integrated with descending visual cues to control wing kinematics and the resultant aerodynamic force production during flight.

High-Speed Shadowgraphy Measurements of an Erosive Particle-Laden Jet Under High-Pressure Compressor Conditions

2017 ◽  
Author(s):  
M. Hufnagel ◽  
C. Koch ◽  
S. Staudacher ◽  
C. Werner-Spatz
Keyword(s):  
Dimensional Analysis ◽  
Particle Velocity ◽  
High Speed ◽  
Fluid Velocity ◽  
Measurement Techniques ◽  
Real Life ◽  
Negative Influence ◽  
Solid Particles ◽  
Flat Plates ◽  
Aerodynamic Properties

Erosive damage done to jet engine compressor blading by solid particles has a negative influence on the compressor aerodynamic properties and hence decreases performance. The erosive change of shape has been investigated in a multitude of experiments ranging from eroding flat plates to eroding full engines. The basic challenge to transfer the results from very simple tests to real life erosion remains. Up to date measurement techniques today allow closing this gap. The necessary experimental and analytical steps are shown. The erosion resistance of Ti-6Al-4V at realistic flow conditions with fluid velocities ranging from 200 to 400 m/s is used. The erodent used was quartz sand with a size distribution corresponding to standardized Arizona Test Dust A3 (1 to 120 μm). Flat plates out of Ti-6Al-4V were eroded at different impingement angles. The particle velocities and sizes were investigated using a high speed laser shadowgraphy technique. A dimensional analysis was carried out to obtain nondimensional parameters suitable for describing erosion. Different averaging methods of the particle velocity were examined in order to identify a representative particle velocity. Compared to the fluid velocity and the mean particle velocity, the energy averaged particle velocity is found to be the best representation of the erosiveness of a particle stream. The correlations derived from the dimensional analysis are capable of precisely predicting erosion rates for different rig operating points. The results can be applied to the methodology published in [1].

scholarly journals Design and aerodynamic analysis of an Automotive Adaptive Rear Diffuser

2021 ◽  
Vol 9 (8) ◽  
pp. 1611-1626
Author(s):  
Heet Patel
Keyword(s):  
Fuel Economy ◽  
High Speed ◽  
Electronic Circuit ◽  
Aerodynamic Drag ◽  
Vital Role ◽  
Aerodynamic Forces ◽  
Aerodynamic Efficiency ◽  
Speed Stability ◽  
Diffuser Angle ◽  
Aerodynamic Lift

Abstract: Traditional vehicles are designed to bring out the best performance, good fuel economy, fewer emissions, and good high-speed stability. In this process of designing a vehicle, the underbody geometry of a car plays a vital role and is often neglected because of its complicated design bits. Though the presence of uneven surfaces causes the layers of air to separate resulting in generating turbulence. This report is about designing an active rear diffuser of a car. The rear diffuser is an aerodynamic device that is installed in the end part of the underbody of a car. Diffuser now a day is quite a common aerodynamic device that is used in performance cars. The main moto of attaching a diffuser is to reduce the wake produced behind the car and help the streamlines to converge better. The prime focus of this study is to design an active rear diffuser that will not only help in providing great high-speed stability and aerodynamic efficiency but will also use the aerodynamic forces adversely to help the car stop faster and on its track. This is made possible first by understanding the effects of diffuser angle on the aerodynamic forces acting on the car. Further, to actually transform the computational values into a working model, an electronic circuit is designed which mimics the exact movement of the diffuser according to the speed and other driving conditions. Keywords: Adaptive, diffuser, automobile, aerodynamic, aerodynamic Drag, aerodynamic Lift

scholarly journals Hexafly-INT Experimental Flight Test Vehicle (EFTV) Aero-Thermal Design

2017 ◽  
Author(s):  
Roberto Scigliano ◽  
Giuseppe Pezzella ◽  
Sara Di Benedetto ◽  
Marco Marini ◽  
Johan Steelant
Keyword(s):  
High Speed ◽  
Thermal Protection ◽  
Flight Test ◽  
Thermal Design ◽  
Test Vehicle ◽  
Aerodynamic Efficiency ◽  
Main Driver ◽  
Readiness Level ◽  
Manufacturing Assembly ◽  
Internal Volume

Over the last years, innovative concepts of civil high-speed transportation vehicles were proposed. In this framework, the Hexafly-INT project intends to test in free-flight conditions an innovative gliding vehicle with several breakthrough technologies on-board. This approach will help to gradually increase the readiness level of a consistent number of technologies suitable for hypervelocity flying systems. The vehicle design, manufacturing, assembly and verification is the main driver and challenge in this project. The prime objectives of this free-flying high-speed cruise vehicle shall aim at a conceptual design demonstrating a high aerodynamic efficiency in combination with high internal volume; controlled level flight at a cruise Mach number of 7 to 8;an optimal use of advanced high-temperature materials and structures. Present research describes the aero-thermal design process of the Experimental Flight Test Vehicle, namely EFTV. The glider aeroshape design makes maximum use of databases, expertise, technologies and materials elaborated in previously European community co-funded projects LAPCAT I & II [1][2], ATLLAS I & II [3][4] and HEXAFLY [5]. The paper presents results for both CFD and Finite Element aero-thermal analysis, performed in the most critical phase of the experimental flight leading to the selection of materials for the different components and to a suitable Thermal Protection System.

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