Effect of engine nacelle layout on sonic boom of supersonic transport

The strong aerodynamic interaction between the nacelles and the wing-body at supersonic speed, and the effect of the exhaust plume on the mainstream shock wave structure could have a great influence on the sonic boom loudness. This paper carries out a numerical investigation on the effect of nacelle layout on thesonic boom for a supersonic transport configuration where the supersonic flows and near field pressure signatures are computed by using a finite volume solver and an adjoint-based Cartesian adaptive mesh refinement method. Various relative positions of nacelles with respect to the wing andthe different number of nacelles are considered. Results indicate that the shock and expansion waves caused by the wing-body combination are significantly interfered with by the lip shock at the inlet, the nozzle trailing edge shock, and the expansion and aft shock of the nozzle plume. This increases the amplitude of the pressure signatures and subsequently increases the sonic boom loudness.Compared with the baseline, the ground loudness can be effectively suppressed by moving the nacelles forward along the chord, outward along the span-wise, and mounting above the wing. Under the same overall force and with the same number of engines and nacelles, the configuration with twin nacelles can reduce the aft shock, but the larger nacelle results in a stronger lip shock at the intake, increasing the loudness of the sonic boom. Thus, considering the engine noise and aerodynamic drag, it is not recommended to deploy twin nacelles for next-generation supersonic transport. © 2023 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.