Investigations of Propulsion Interference Effects on a Transport Aircraft Configuration

In a joint effort ONERA and DLR have assessed the interference effects of a generic twin-engine transport aircraft configuration equipped with through-flow nacelle. 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 substan- tially influenced by interference effects. Comparison of experi- mental and numerical results showed that the solution of the Euler equations is well capable of simulating the interference effects.