Development and identification of an analytical wake vortex model applying vortex line geometries derived from LES

Abstract

One major challenge for investigations on wake vortex encounters in real-time aircraft simulations is to find a compromise between the vortex model’s complexity and accuracy. For realistic encounter simulations effects like vortex deformation during the decay have to be taken into account. In this case the compromise between complexity and accuracy becomes crucial. Existing vortex models are either very generic (straight vortices or generic deformation) or if vortex line deformation is considered most realistically the models are mostly too complex for real-time aircraft simulation (like LES). For this reason DLR’s Institute of Flight Systems developed an analytical vortex model which is able to represent vortices with arbitrary vortex line geometries like e.g. wavy vortices or vortex rings. Geometry parameters describing the vortex line shape have been identified from LES results. For a variety of different atmospheric conditions (in terms of turbulence and temperature stratification) the identified model is able to represent the vortex decay in real-time (including e.g. evolution of circulation, core radius and the vortex shape) very realistically without a huge computational effort. In the future the model shall be combined with the traffic-server of a DLR flight simulator to give e.g. the ability to develop operational systems like wake-evasion-systems in a most realistic environment.