Aerodynamic Considerations for Engine Exhaust Design for Subsonic High Bypass Fan Engines

Analytically and empirically derived external and internal aerodynamic data have been applied to the high-speed cruise development of a low-drag, minimum thrust loss, strut mounted nacelle. The nacelle considered for this study houses a high bypass ratio subsonic fan engine with a short fan duct and a primary plug nozzle. The analysis technique has been geared to a simple geometric description of the nacelle and exhaust system so that high-speed computers may be used to generate trade data. The trade data permit the selection of exhaust systems which, when combined with the complete nacelle, will provide the highest thrust-minus-drag configuration consistent with the airplane cruise mission.