On the Extraction of Long-living Features in Unsteady Fluid Flows
This paper proposes aGalilean invariant generalization of critical points ofvector field topology for 2D time-dependent flows. The approach is based upon a Lagrangian consideration of fluid particle motion. It extracts long-living features, likesaddles and centers, and filters out short-living local structures. This is well suited for analysis ofturbulent flow, where standard snapshot topology yields an unmanageable large number of topological structures that are barely related to the few main long-living features employed in conceptual fluid mechanics models. Results are shown for periodic and chaoticvortex motion.
KeywordsVortex Core Lagrangian Coherent Structure Vortex Region Galilean Transformation Acceleration Magnitude
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The project is part of the SFB 557 “Control of complex turbulent shear flows” and is partially supported by the DFG Emmy Noether program. The authors wish to thank George Haller, Gilead Tadmor, and Igor Mezić for fruitful discussions. All visualizations have been created using Amira - a system for advanced visual data analysis (http://amira.zib.de). The authors further want to thank the reviewers for their suggestions, which helped to improve the paper significantly.
- 1.Panton, R.L.: Incompressible Flow. Wiley & Sons (2005)Google Scholar
- 7.Hunt, J.: Vorticity and vortex dynamics in complex turbulent flows. CSME Trans. 11(1) (1987) 21–35Google Scholar
- 10.Peikert, R., Roth, M.: The parallel vectors operator - a vector field visualization primitive. In: IEEE Visualization ’00. (2000) 263–270Google Scholar
- 13.Fuchs, R., Peikert, R., Sadlo, F., Alsallakh, B., Gröller, E.: Delocalized unsteady vortex region detectors. In O. Deussen, D. Keim, D.S., ed.: VMV ’08. (October 2008) 81–90Google Scholar
- 14.Shi, K., Theisel, H., Weinkauf, T., Hege, H.C., Seidel, H.P.: Finite-time transport structures of flow fields. In: IEEE Pacific Visualization ’08. (2008) 63–70Google Scholar
- 19.Soille, P.: Morphological image analysis. Springer Berlin (1999)Google Scholar