By means of a vortex-filament technique and large-eddy simulations the dynamics during the jet regime of the wake of a subsonic aircraft cruising in a stably stratified and turbulent atmosphere is simulated. The imposed methods are briefly outlined. The major issues as the roll-up process of the vortex sheet around the wings into the wingtip vortices, the effect of the vortices upon the deformation and displacement of the exhaust jets, and the resulting distribution of the exhaust are addressed. It is found that the roll-up process already significantly displaces the exhaust jets. The evolving wingtip vortices attract the exhaust and collect it around the vortex cores. This entrainment is further controlled by the buoyancy force of the hot exhaust whereas the body of the aircraft, as a source of circulation disturbation, has no significant influence. Histories of temperature and species concentration can be used to determine th-duration of the jet regime which, for a cruising B-747 aircraft, lasts for 20 +/- 2 s. During that time the temperature of the trapped exhaust decays to the ambient value and then rises again. Likewise, the exhaust concentration drops to 0.03% of its initial value but then stays constant during thp vortex regime. Throughout the jet regime the species are inhomogeneously mixed around the vortex cores with half-moon shaped local maxima. Atmospheric turbulence has no significant impact on the evolution of the wake in the jet regime.
