Fast vortex axis calculation using vortex features and identification algorithms

Abstract

Knowledge about the vortical flow over delta wings, its structure and behavior is an essential issue for the development of highly maneuverable aircraft and high angle of attack flight. Vortex breakdown is one of the limiting factors of extreme maneuvers in flight and poses a difficulty for flight control. The demand of simulating the vortical flow behavior has pushed the limits of current CFD Codes, but also the requirements for advanced post processing tools. From the analysis point of view, an important requirement is the capability to identify vortical flow patterns such as the vortex axis lines, vortex hull surfaces, and vortex-vortex interactions. This information is significant for a deeper physical understanding of various vortical flow phenomena and for flight control of aircrafts. One goal of this paper is to compare various typical vortex identification methods, applied to the vortical flow over a generic 65° swept delta wing. Another goal is to apply those methods as elements of a construction kit, which defines a fast algorithm to detect and calculate vortex axes.