Investigations of strake wake vortices in a high-lift-configuration using Stereo-PIV

Kurzfassung

Stereo PIV measurements were performed within the EUROLIFT II framework in the LSWT (AD, Bremen) test section with a width of 2.1 x 2.1 on the Airbus like KH3Y half model with a half span of 1,4 m in a high-lift-configuration. The reference atmospheric on flow conditions for the measurements were: • V = 60 m/sec • M = 0,175 • Rec = 1.3 x 106. For the engine/airframe integration studies a new through-flow-nacelle and a pylon were designed and manufactured. Additionally a strake device, a small vortex generator, was mounted on an optimal position on the inboard side of the nacelle in order to increase the lift coefficient cL at high angles of attack. In this framework 300 instantaneous 3C-velocity vector fields were measured each in 5 cross flow planes along the flow direction on the suction side of the wing by a traversable Stereo PIV system. The goal of the test programme was to track the trajectory of the wake vortex of an optimal strake at several chord positions between the nacelle and the flap of the wing and at 3 different angles of incidence: 7°, 16.5° and 18.5°. In parallel the two configurations at 7° and 16.5° were measured without the strake for comparison reasons. In total more than 8000 instantaneous 3C-velocity vector fields were calculated. This data provides information to understand the physical process of the stabilising effect of the strake wake vortex on the separated flow on the wing, which is caused by the wake of the nacelle, pylon and slat-cut-out. The PIV results will also be used for the validation of and the comparison with numerical simulations.