Vortex identification and tracking in unsteady flows

The present Note deals with the identification and tracking of vortices in a time-resolved unsteady flow. The approach is based on the combination of two existing post-processing tools that are Galilean invariant functions: feature flow field f and vortex identification algorithm γ2. An analytical development shows that the joint use of γ2 and the streamlines of f allows to identify and track the location of the center of a vortex core with a non-zero convection velocity. We discuss the applicability of this procedure to actual flows for which the assumptions of the analytical approach may not be strictly valid. The procedure is validated using PIV measurements performed in an oscillating flow in a model of thermoacoustic refrigerator. This method proves to be efficient for the automated analysis of convection processes when large numbers of vortices are involved. To cite this article: A. Berson et al., C. R. Mecanique 337 (2009).