Revealing unsteady flow structure from flow visualization images
Flow visualization images of unsteady high Reynolds number flows contain a wealth of information about the flows from which they are obtained. Unfortunately, the primary structure in the flow is often obscured by smaller structures. In addition, periodic and quasi-periodic flows often require large data sets to fully characterize them. In this article, the application of the Proper Orthogonal Decomposition (POD) to flow visualization images of a turbulent swirling jet and in the near wake behind a bluff body is considered. The results show the ability of POD to isolate the larger, more important structure. In the quasi-periodic wake flow, the results of applying POD may be used further to recreate the typical dynamic behavior of the flow. Furthermore, the modal description of the flow obtained through POD analysis provides unique insight into the unsteady flow structure and its relative importance to the flow. As a result, POD enables the extraction of information from flow visualization imagery well beyond that possible from simple inspection.
KeywordsVortex Particle Image Velocimetry European Physical Journal Special Topic Coherent Structure Proper Orthogonal Decomposition
Unable to display preview. Download preview PDF.
- 4.V. Durgesh, J.W. Naughton, A IAA Paper 2006-3186 (2006)Google Scholar
- 5.V. Durgesh, J.W. Naughton, In Proceedings of the 13th International Symposium on Flow Visualization, edited by J. P. Prenel Y. Bailly (2008), Paper 117Google Scholar
- 6.V. Durgesh, J.W. Naughton, Exp. in Fluids (accepted for publication, available online) (2010)Google Scholar
- 7.V. Durgesh, J.W. Naughton, S.A. Whitmore, AIAA Paper 2004-0904 (2004)Google Scholar
- 8.R.T. Gilchrist, J.W. Naughton, A IAA Paper 2002-0442 (2002)Google Scholar
- 10.M.N. Glauser, W.K. George, in Sixth Symposium on Turbulent Shear Flows, 10.1.1–10.1.6 (1987)Google Scholar
- 13.P. Holmes, J. Lumley, G. Berkooz, Turbulence, Coherent Structures, Dynamical Systems and Symmetry (Cambridge University Press, 1996)Google Scholar
- 17.J.L. Lumley, in Atmospheric Turbulence and Radio Wave Propogation, edited by A.M. Yalglom, V.I. Tatarski (Nauka, Moscow, 1967), p. 166Google Scholar
- 19.M.S. Saini, J.W. Naughton, T. Yamashita, H. Nagai, K. Asai, A IAA Paper 2008-4073 (2008)Google Scholar
- 20.R. Semaan, J.W. Naughton, D. Ewing, A IAA Paper 2009-1114 (2009)Google Scholar