Leading-Edge Vortex Interactions at a Generic Multiple Swept-Wing Aircraft Configuration

Experimental investigations on a generic low-aspect-ratio aircraft configuration with triple and double delta wing planforms were performed at subsonic speed. Flowfield measurements by means of stereoscopic particle image velocimetry and force and moment measurements are used to investigate the system of interacting leading-edge vortices and its effect on the stability characteristics. The analysis comprises the discussion of the overall flowfield and of the vortex system including breakdown locations, vortex core data, and vortex trajectories. Topology considerations in selected crossflow sections highlight the flow patterns of the vortex system. The stability characteristics are discussed by means of the associated aerodynamic moment derivatives. Both the triple and double delta wing configurations feature a flowfield dominated by inboard and midboard vortices. The inboard vortex develops at a nonslender or slender wing section for the triple or double delta wing configurations, respectively, which entails different vortex characteristics and vortex–vortex interaction characteristics. The breakdown behavior associated with the different vortex types influences the stability of the midboard vortex in different ways. Both configurations exhibit pronounced instabilities in the medium to high angle-of-attack regimes, whereas the onset and magnitude of the instability are attenuated for the triple delta wing configuration.