COMPUTER VISUALIZATION OF VORTEX WAKE SYSTEMS

This paper evaluates several methods for vortex detection in computed rotary-wing flowfields. As part of this process, we demonstrate that vortex detection methods based on centers of swirling flow may fail for multiple vortices with overlapping rotational cores. To remedy this problem, we propose a new vortex detection scheme based on searches for local maxima of vorticity throughout the flowfield. This scheme has a straightforward physical interpretation and is easy to implement for structured-grid datasets. Results from this vortex detection method show good agreement with cross-sectional plots for vorticity contours. Results for computed rotary-wing flowfields distinctly show the trajectories of the blade tip and root vortices as well as the overall vortex rollup at the sides of the rotor disk.