Three-Dimensional Solution of Flows over Wings with Leading-Edge Vortex Separation

AIAA Journal ◽  
1976 ◽  
Vol 14 (4) ◽  
pp. 519-525 ◽  
Author(s):  
James A. Weber ◽  
Guenter W. Brune ◽  
Forrester T. Johnson ◽  
Paul Lu ◽  
Paul E. Rubbert
Keyword(s):  
Three Dimensional ◽  
Leading Edge ◽  
Dimensional Solution ◽  
Leading Edge Vortex ◽  
Vortex Separation ◽  
Edge Vortex

Three-Dimensional Flow over Wings with Leading-Edge Vortex Separation

AIAA Journal ◽  
1980 ◽  
Vol 18 (4) ◽  
pp. 367-380 ◽  
Author(s):  
F. T. Johnson ◽  
E. N. Tinoco ◽  
P. Lu ◽  
M. A. Epton
Keyword(s):  
Three Dimensional ◽  
Leading Edge ◽  
Three Dimensional Flow ◽  
Leading Edge Vortex ◽  
Dimensional Flow ◽  
Vortex Separation ◽  
Edge Vortex

scholarly journals The leading-edge vortex on a rotating wing changes markedly beyond a certain central body size

2018 ◽  
Vol 5 (7) ◽  
pp. 172197 ◽  
Author(s):  
Shantanu S. Bhat ◽  
Jisheng Zhao ◽  
John Sheridan ◽  
Kerry Hourigan ◽  
Mark C. Thompson
Keyword(s):  
Reynolds Number ◽  
Body Size ◽  
Central Body ◽  
Three Dimensional ◽  
Leading Edge ◽  
Particle Image Velocimetry Technique ◽  
Leading Edge Vortex ◽  
Rapid Acquisition ◽  
Edge Vortex ◽  
Rotating Wing

Stable attachment of a leading-edge vortex (LEV) plays a key role in generating the high lift on rotating wings with a central body. The central body size can affect the LEV structure broadly in two ways. First, an overall change in the size changes the Reynolds number, which is known to have an influence on the LEV structure. Second, it may affect the Coriolis acceleration acting across the wing, depending on the wing-offset from the axis of rotation. To investigate this, the effects of Reynolds number and the wing-offset are independently studied for a rotating wing. The three-dimensional LEV structure is mapped using a scanning particle image velocimetry technique. The rapid acquisition of images and their correlation are carefully validated. The results presented in this paper show that the LEV structure changes mainly with the Reynolds number. The LEV-split is found to be only minimally affected by changing the central body radius in the range of small offsets, which interestingly includes the range for most insects. However, beyond this small offset range, the LEV-split is found to change dramatically.

Characterization of a Three-Dimensional Leading-Edge Separation Bubble on Swept, Low Aspect-Ratio Propeller Blades

2017 ◽  
Author(s):  
Ye-Bonne Koyama Maldonado ◽  
Gregory Delattre ◽  
Cedric Illoul ◽  
Clement Dejeu ◽  
Laurent Jacquin
Keyword(s):  
Delta Wing ◽  
Separation Bubble ◽  
Three Dimensional ◽  
Leading Edge ◽  
Time Resolved ◽  
Leading Edge Vortex ◽  
Wall Structures ◽  
Edge Vortex ◽  
Propeller Blades ◽  
Leading Edge Vortices

Leading-edge vortex flows are often present on propeller blades at take-off, however, their characteristics and aerodynamic impact are still not fully understood. An experimental investigation using Time Resolved Particle Image Velocimetry (TR-PIV) has been performed on a model blade in order to classify this flow with respect to both delta wing leading-edge vortices and the low Reynolds number studies regarding leading-edge vortices on rotating blades. A numerical calculation of the experimental setup has been performed in order to assess usual numerical methods for propeller performance prediction against TR-PIV results. Similar characteristics were found with non slender delta wing vortices at low incidence, which hints that the leading-edge vortex flow may generate vortex lift. The influence of rotation on the characteristics of the leading-edge vortex is compared to that of the pressure gradient caused by the circulation distribution. A discussion on the quality of the PIV reconstruction for close-wall structures is provided.

scholarly journals The three–dimensional leading–edge vortex of a ‘hovering’ model hawkmoth

1997 ◽  
Vol 352 (1351) ◽  
pp. 329-340 ◽  
Author(s):  
Coen van den Berg ◽  
Charles P. Ellington
Keyword(s):  
Wing Length ◽  
Three Dimensional ◽  
Axial Flow ◽  
Leading Edge ◽  
Tip Vortex ◽  
Flow Visualisation ◽  
High Lift ◽  
Leading Edge Vortex ◽  
Edge Vortex ◽  
Wing Chord

Recent flow visualisation experiments with the hawkmoth, Manduca sexta , revealed small but clear leading–edge vortex and a pronounced three–dimensional flow. Details of this flow pattern were studied with a scaled–up, robotic insect (‘the flapper’) that accurately mimicked the wing movements of a hovering hawkmoth. Smoke released from the leading edge of the flapper wing confirmed the existence of a small, strong and stable leading–edge vortex, increasing in size from wingbase to wingtip. Between 25 and 75 % of the wing length, its diameter increased approximately from 10 to 50 % of the wing chord. The leading–edge vortex had a strong axial flow veolocity, which stabilized it and reduced its diamater. The vortex separated from the wing at approximately 75 % of the wing length and thus fed vorticity into a large, tangled tip vortex. If the circulation of the leading–edge vortex were fully used for lift generation, it could support up to two–thirds of the hawkmoth's weight during the downstroke. The growth of this circulation with time and spanwise position clearly identify dynamic stall as the unsteady aerodynamic mechanism responsible for high lift production by hovering hawkmoths and possibly also by many other insect species.

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