Analysis of Vortex Flow Phenomena on Generic Delta Wing Planforms at Subsonic Speeds

Experimental and numerical investigations on the vortex dominated flow at a double and triple delta wing configuration at low subsonic speed are presented. Forces and moments obtained from wind tunnel tests and numerical simulations, as well as flow-field data obtained by stereo particle image velocimetry are discussed. The flow field is dominated by two interacting leading-edge vortices. The interaction of the vortices very much depends on the relative sweep of the leading-edges and ranges from independent movement via merging to a complex breakdown pattern of the vortex system. The loss of the strong interaction leads to a pitch up tendency and roll reversal. For the double delta wing, this happens at higher angles of attack and more abrupt, and therefore results in a sudden instability. The numerical results show a satisfying agreement with the wind tunnel data, but need further evaluation to clarify the usability for a more detailed analysis of the flow field.