Flow characteristics of diamond and lambda wings at different flight conditions

The aim of this study is to investigate the time-averaged flow structure around a nonslender diamond and lambda wing using a laser based 3-dimessional Particle Image Velocimetry (PIV) technique. The flow structure in close region of the stationary diamond wing surface and formation of the vortex breakdown were studied by varying the yaw angle of the wing within the range of 0 ? ? ? ?15 ? for the angle of attack of ????? and ??? .Secondly, the flow structure in the near-surface and other crosssections of the wing and formation of the vortex breakdown were investigated by varying the angle of attack of the wing within the range of 7o? ? ?17o.Finally, a lambda wing is subjected to small-amplitude perturbations over a range of periods to simulate leading-edge vortex control concepts. Perturbations near the inherent frequency of the predominantly unsteady flow event on the stationary wing yield substantial changes of the near surface flow structure. Experimental analyses are composed of time-average patterns of streamlines, contours of vorticity distributions, Reynolds stress correlations, transverse and streamwise velocity components, distribution of fluctuating velocities and turbulent kinetic energy.