Dergi makalesi Açık Erişim

Near-surface particle image velocimetry measurements over a yawed slender delta wing

2021    Karasu, Ilyas; Tumse, Sergen; Tasci, Mehmat O.; Sahin, Besir; Akilli, Huseyin

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, beta, on the vortical flow structure formed on a slender delta wing. This sideslip angle, beta, in the yaw plane was varied from 4 degrees up to 20 degrees with an interval of 4 degrees at two critical angles of attack, alpha = 25 degrees and 35 degrees, respectively. In order to reveal the influence of the yaw angle, beta 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 beta = 8 degrees, becomes to be effective on the flow characteristics of the delta wing, and this effect was augmented with increasing beta. The influence of beta is quite high on the vortical flow structure at alpha= 35 degrees compared to the angle of attack of alpha = 25 degrees. 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 beta. Furthermore, the extent of the asymmetry enlarges with increasing beta. 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.