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Vortices in fluid and gas are very stable formations featuring a slow mass, momentum and energy exchange with surrounding atmosphere. The «closure» of vortices, on the one hand, facilitates their visualization and, on the other hand, results in accumulating and for long retaining hot engine exhaust gases entrained into the vortices in the stage of their formation in the near jet-vortex wake behind an aircraft. The later problem is closely related to the environmental impact of aviation, especially within airport areas and ozone layer of the Earth atmosphere. In this paper the problem of light scattering by particulates arising during water vapor condensation, droplet coagulation or breakdown is considered. Numerical results are presented of gasdynamic and optical properties of the aerosol-containing wakes of the Boeing-747-type aircraft and of the prospective Russian second-generation supersonic civil transport SST-2.

The paper deals with restrictions on airport capacity associated with the potential hazard for an aircraft in takeoff or landing to encounter the vortex wake generated by another aircraft. The complexity of the problem under study and the lack of a single research tool make one employ a “mosaic” approach based on combined use of various methods. A specific difficulty therewith appears of asymptotically non-rigorous division of the problem into subproblems and of thoroughly matching the results obtained. The goal of this work is to validate and assess the potentialities of the methods used and to reveal their weaknesses and strengths as well as to discuss the results obtained.

The problem of decreasing separation distances between aircraft during their takeoffs and landings is investigated. This work presents a general view on the problem under study, whose complexity lies basically in the fundamental impossibility to create a single method and universal tool of investigation. A fragmentary approach is used with asymptotically non-strict splitting of the problem into several subproblems. The formulations of the subproblems are considered, the potentialities of the research tools are assessed, the ways and phases of model refinement are outlined. Some concrete measures are discussed for decreasing safe separation distances between aircraft.