DOWNWASH AT THE TAIL OF SWEPT-WING TRANSPORTS WITH HIGH-LIFT DEVICES

A set of analytical expressions has been derived from classical aerodynamic theory to model the airflow behind a swept wing with high-lift devices deployed, including the effects of vertical displacement and rolling-up of the vortex sheet. Simple approximations have been developed to facilitate readily application in the preliminary design phase. The effect of rear fuselage-mounted nacelles has been incorporated. Validation by comparison with theory and experimental data for 8 transport aircraft of various configurations showed good agreement for the downwash gradient for all slat and flap settings, except when the tail is very close to the vortex sheet. The non-lift dependent downwash showed an error band of 1 degree for all aircraft except one. Nomenclature