21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-3.8.2

VORTICAL FLOWFIELD STRUCTURE AT FORWARD SWEPT WING CONFIGURATIONS

Breitsamter C., Laschka B.
TU Munich, Germany

Keywords: vortical flowfield structure, swept wing configurations

Comprehensive flowfield investigations have been carried out on forward swept wing configurations with wing sweep of -40 deg. The present study focus on a generic wing-body model complemented by aft swept canards. For the canard-off and canard-on configurations instantaneous velocities were measured in several cross-flow planes using advanced hot-wire anemometry. The tests were made at 10, 20, and 30 deg angle of-attack at a Reynolds number of 0.46 x 10^6. Detailed surveys of mean and rms velocities show that free vortex sheets are generated at the wing leading edge which roll up into strong leading-edge vortices. Their rotation is opposite to that of the tip vortices. Bursting over the wing occurs already at moderate angles of attack. At higher incidences a trailing-edge vortex is shed along the inner part of the wing which is counter-rotating in sense to the leading-edge vortex. The canard vortices pass the wing leading-edge relatively high, and after the onset of wing vortices they are moved upwards and outboard. The interference between these vortices is studied in detail analyzing the associated turbulent flow structure. Downstream of wing vortex bursting the highest turbulence intensities are found in an annular region around the vortex center, where fluctuations are channeled into a narrow-band.

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