Vortex Interaction in Transonic Flow for Wing-Mounted UHBR Nacelles

Kurzfassung

In this work upper wing vortices originating from the installation of a closely coupled UHBR nacelle on a long range transport aircraft are investigated under high speed flight conditions. Flow conditions at moderate angle of attack as well as high speed stall are considered. The investigations are executed by means of RANS simulations using a eynolds stress turbulence model. It was found that a horseshoe vortex forms on the pylon leading edge at the intersection with the nacelle surface. The inboard part of the horseshoe vortex is deflected by the pressure field of the wing forcing it to pass over its suction side through the transonic flow field. A second vortex is found originating from the nacelle and passing over the wing without significantly altering the wing pressure distribution. Furthermore, for high angles of attack a strong vortex emerges from a corner separation in the pylon-wing intersection resulting in a flow separation towards the wing trailing edge.