Study on flow behavior and structure over chined fuselage at high angle of attack

Abstract

A study of leeward vortex structure over chined fuselage and the effects of micro tip perturbation on its vortex flow have been carried out in wind tunnel experiments at Reynolds numbers from 1.26×105 to 5.04×105 with PIV and pressure measurement techniques. Firstly, the experiment results have proved that micro tip perturbation has no effects on the vortex flow and its aerodynamic characteristics over chined fuselage at high angle of attack, in which there are not any non-deterministic flow behaviors. Secondly, the evolution of leeward vortex structure over chined fuselage along the axis of model can be divided into four flow regimes: linear conical developed regime, decay regime of leeward vortex intensity, asymmetric leeward vortex break down regime and completely break down regime. And a correlation between leeward vortex structure and sectional aerodynamic force was also revealed in the present paper. Thirdly, the experiment results show the behavior of leeward vortex core trajectories and zonal characteristics of leeward vortex structure with angles of attack. Finally, the experiment results of Reynolds number effect on the leeward vortex flow have further confirmed research conclusions from previous studies: the flows over chined fuselage at high angles of attack are insensitive to variation of Reynolds number, and there is a little effect on the secondary boundary layer separation and the suction peak induced by leeward vortex.