Stereo-PIV Measurements of Vortex-Interaction Effects on Generic Delta Wing Planforms

Low aspect ratio configurations with leading-edge vortex dominated flow exhibit typical flight mechanicsinstabilities like a pitch-up or a roll reversal at medium to high angles of attack. Those are linked to thebursting of leading-edge vortices. An approach that might be able to tackle these instabilities is the intendedtriggering of multiple, interacting leading-edge vortices. Therefore, the system of interacting leading-edgevortices on a double delta wing and a triple delta wing configuration was investigated by means of stereoparticle image velocimetry measurements at asymmetric free stream conditions. Cross-flow sections weremeasured on the windward and leeward wing sides to obtain comprehensive information about the asymmet-ric flow structures. Both configurations indicate a system of an inboard leading-edge vortex and a midboardleading-edge vortex at each wing side. The inboard leading-edge vortex develops at a highly swept or a amedium swept wing section for the double or the triple delta wing configuration, respectively. The fully-developed vortex systems at the leeward wing side and the vortex system exhibiting vortex bursting at thewindward wing side show significant differences between both configurations. The characteristics of thevortex interaction are dominated by the state of the inboard leading-edge vortex and thus, by the propertiesof the inboard wing section. As a result, the triple delta wing features a more upstream and less abruptvortex breakdown due to the reduced wing sweep of the inboard wing section and the associated vortexinteraction.     «

Low aspect ratio configurations with leading-edge vortex dominated flow exhibit typical flight mechanicsinstabilities like a pitch-up or a roll reversal at medium to high angles of attack. Those are linked to thebursting of leading-edge vortices. An approach that might be able to tackle these instabilities is the intendedtriggering of multiple, interacting leading-edge vortices. Therefore, the system of interacting leading-edgevortices on a double delta wing and a triple delta wing configurati...     »