Particle Image Velocimetry Measurements on a Delta Wing with Periodic Forcing

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


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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