Investigations of propulsion integration interference effects on a transport aircraft configuration

Abstract

In a joint effort ONERA and DLR have assessed the interference effects of a generic twin-engine transport aircraft configuration equipped with throughflow nacelles. Both experimental and theoretical investigations were performed. The results showed that the installation of the nacelles had substantial effects on total forces at cruise Mach number. With respect to the clean configuration, total lift decreased at constant incidence, and total drag increased at constant lift. A detailed analysis of the flowfield revealed that for transonic flows the installation of the nacelle influenced the complete upper wing surface. On the lower wing surface the flow was considerably accelerated due to the propulsion system, and a supersonic region terminated by a shock wave appeared. The nacelle pressure distribution was also substantially influenced by interference effects. Comparison of experimental and numerical results showed that the solution of the Euler equations is well capable of simulating the interference effects.