INVESTIGATIONS OF PROPULSION INTEGRATION 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 wi th throughflow nacelles. Both experimental and theoretical investigati ons were performed. The results showed that the installation of the na celles had substantial effects on total forces at cruise Mach number. With respect to the clean configuration, total lift decreased at const ant incidence, and total drag increased at constant lift. A detailed a nalysis of the flowfield revealed that for transonic flows the install ation of the nacelle influenced the complete upper wing surface. On th e lower wing surface the flows 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 in fluenced by interference effects. Comparison of experimental and numer ical results showed that the solution of the Euler equations is well c apable of simulating the interference effects.