Vortical flowfield structure at forward swept-wing configurations

Extensive aerodynamic investigations have been carried out on forward swept-wing configurations with a wing sweep of -40 deg. A generic wing-body model with removable aft swept canards is used to measure the instantaneous velocities in several crossflow planes applying advanced hot-wire anemometry. The tests mere 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 at moderate angles of attack strong wing leading-edge vortices are generated rotating opposite in a sense to the wing tip vortices. At higher incidences trailing-edge vortices are shed at the inner-wing part with the same sense of rotation as the wing tip vortices. The canard vortices pass the wing leading-edge relatively high, and after the onset of wing vortices they are moved upward and outboard, The interference between these vortices is studied in detail by analyzing the associated turbulent flow structure. Vortex bursting over the wing occurs already at moderate angles of attack. Downstream, the highest turbulence intensities are found in an annular region around the burst vortex core, where fluctuations are significantly channeled into a narrow band.