Laser-scanning particle image velocimetry applied to a delta wing in transient maneuver

1993 ◽  
Vol 15 (3) ◽  
pp. 159-167 ◽  
Author(s):  
C. Magness ◽  
O. Robinson ◽  
D. Rockwell
Author(s):  
T Lee ◽  
LS Ko

The vortex flow and lift force generated by a 50°-sweep non-slender reverse delta wing were investigated via particle image velocimetry, together with flow visualization and force balance measurement, at Re = 11,000. The non-slender reverse delta wing produced a delayed stall but a lower lift compared to its delta wing counterpart. The stalling mechanism was also found to be triggered by the disruption of the multiple spanwise vortex filaments developed over the upper wing surface. The vortex flowfield was, however, characterized by the co-existence of reverse delta wing vortices and multiple shear-layer vortices. The outboard location of the reverse delta wing vortex further implies that the lift force is mainly generated by the wing lower surface while the upper surface acts as a wake generator. The spatial progression of the flow parameters of the vortex generated by the non-slender reverse delta wing as a function of α was also discussed.


Author(s):  
Piotr M. Domagalski ◽  
Michal M. Mielnik ◽  
Ingrid Lunde ◽  
Lars R. Sætran

This paper presents the characteristics of hydrodynamically focused streams to be used in Microscale Particle Image Velocimetry (micro-PIV). The investigation was done by means of Confocal Laser Scanning Microscopy (CLSM) in channels of cross sections 260 × 200 μm and 1040 × 800 μm, within the downstream velocities range from 0,1 to 2,5 cm/s. The formulation of a curvature of the sheet, its dependence on the side stream ratio and overall downstream velocity is discussed qualitatively and quantitatively. The results show that the curvature is highly dependent on the velocities of the system. Sheet characteristics such as curvature and observed sheet width variation become amplified with higher velocities. This leads to conclusion that hydrodynamic focusing is promising as a selective seeding technique for use in micro-PIV up to velocities of few cm/s. However, the fact that this is the upper velocity range in microfluidics, renders the SeS-PIV technique as a very suitable tool for complicated flows visualization.


1993 ◽  
Vol 14 (3) ◽  
pp. 181-192 ◽  
Author(s):  
D. Rockwell ◽  
C. Magness ◽  
J. Towfighi ◽  
O. Akin ◽  
T. Corcoran

2004 ◽  
Vol 41 (6) ◽  
pp. 1393-1403
Author(s):  
Stefan Siegel ◽  
Thomas E. McLaughlin ◽  
Julie A. Albertson

1992 ◽  
Vol 29 (4) ◽  
pp. 707-709 ◽  
Author(s):  
C. Magness ◽  
O. Robinson ◽  
D. Rockwell

Author(s):  
Ilyas Karasu ◽  
Sergen Tumse ◽  
Mehmat O. Tasci ◽  
Besir Sahin ◽  
Huseyin Akilli

In this study, extensive instantaneous velocity measurements were conducted within a flow area by stereo particle image velocimetry (SPIV) to investigate the influence of the yaw angle, β, on the vortical flow structure formed on a slender delta wing. This sideslip angle, β, in the yaw plane was varied from 4° up to 20° with an interval of 4° at two critical angles of attack, α = 25° and 35°, respectively. In order to reveal the influence of the yaw angle, β over the flow structure of the delta wing, time-averaged flow statistics, and instantaneous flow data obtained by the SPIV technique in the plan-view plane close to the suction surface of the delta wing were presented. It was observed that even a low yaw angle, for instance β = 8°, becomes to be effective on the flow characteristics of the delta wing, and this effect was augmented with increasing β. The influence of β is quite high on the vortical flow structure at α= 35° compared to the angle of attack of α = 25°. The flow structure that is symmetrical with respect to the centerline of the wing in the case of no yaw has disrupted with the existence β. Furthermore, the extent of the asymmetry enlarges with increasing β. The leading-edge vortex (LEV) on the windward side broken earlier and dominated the flow on the wing surface. It is concluded that this asymmetric flow structure can deteriorate the aerodynamic performance and cause other adverse effects such as unsteady loading.


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