Journal ArticleDOI
Wind tunnel tests of wings at Reynolds numbers below 70 000
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In this article, a planform wing was tested at Reynolds numbers as low as 20 000 in a low turbulence wind tunnel and the best profile was a thin plate with a 5% circular arc camber.Abstract:
Rectangular planform wings were tested at Reynolds numbers as low as 20 000 in a low turbulence wind tunnel. The lift and drag measurements on a NACA 0012 profile were compared with those for thin flat and cambered plates. For all Reynolds numbers below 70 000 the best profile was a thin plate with a 5% circular arc camber. At all turbulence levels this profile produced the greatest lift-drag ratio, and had the highest lift coefficient at all angles of attack. The 5% camber and all of the thin plates tested were relatively insensitive to either a variation in the Reynolds number, or an increase in the wind tunnel turbulence level, whereas the NACA 0012 was very seriously affected by either, at Reynolds numbers below 50 000.read more
Citations
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Low Reynolds Number Aerodynamics of Low-Aspect-Ratio, Thin/Flat/Cambered-Plate Wings
TL;DR: In this paper, the authors measured the lift, drag, and pitching moment about the quarter chord on a series of thin flat plates and cambered plates at chord Reynolds numbers varying between 60,000 and 200,000.
Journal ArticleDOI
Leading-edge vortex improves lift in slow-flying bats.
Florian T. Muijres,L. C. Johansson,R. Barfield,Marta Wolf,Geoffrey R. Spedding,Anders Hedenström +5 more
TL;DR: Using digital particle image velocimetry, it is shown that a small nectar-feeding bat is able to increase lift by as much as 40% using attached leading-edge vortices during slow forward flight, resulting in a maximum lift coefficient of 4.8.
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Bat Flight Generates Complex Aerodynamic Tracks
TL;DR: It is shown that the wakes of a small bat species differ from those of birds in some important respects, and interpretations of the unsteady aerodynamic performance and function of membranous-winged, flapping flight should change modeling strategies for the study of equivalent natural and engineered flying devices.
Journal ArticleDOI
Basic Understanding of Airfoil Characteristics at Low Reynolds Numbers (104–105)
TL;DR: A computational study has been conducted on various airfoils to simulate flows at Reynolds numbers (Re) primarily between 104 and 105 to provide understanding and guidance for MAV and other low-Rey numbers.
Aerodynamic Measurements at Low Raynolds Numbers for Fixed Wing Micro-Air Vehicles
TL;DR: In this article, a new platform force and moment balance, similar to an already existing balance, was designed and built to perform lift, drag and moment measurements at low Reynolds numbers Balance characteristics and validation data are presented Results show a good agreement between published data and data obtained with the new balance.
References
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Journal ArticleDOI
Experimental Studies of Separation on a Two-Dimensional Airfoil at Low Reynolds Numbers
TL;DR: In this paper, the laminar separation, transition, and turbulent reattachment near the leading edge of a two-dimensional NACA 663 -018 airfoil were investigated using a low-speed, smoke visualization wind tunnel.
Low Reynolds Number Vehicles
TL;DR: In this paper, the authors present the present status and future possibility of airfoil design and evaluation at subcritical speeds to meet the needs for these applications, including remotely piloted vehicles (RPV's), sailplanes, ultra-light man-carrying/man-powered aircraft, mini-RPVs at low altitudes and wind turbines/propellers.
Journal ArticleDOI
Aerodynamic testing at low Reynolds numbers
TL;DR: In this article, Wortmann et al. etudie l'influence des techniques de montage du modele sur la precision des donnees, i.e., la turbulence and les perturbations acoustiques alterent le comportement de l'aile au decrochage.
Aerodynamics of the model airplane. Part 1 - Airfoil measurements
TL;DR: In this paper, the behavior of wing sections in low-turbulence stream in Reynolds number range from 20,000 to 170,000, and the number of wing segments in the Reynolds number was estimated to be between 170, 000 and 200,000.