Dynamic K-L analysis of coherent structures based on DNS of turbulent Newtonian and viscoelastic flows |
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| Authors: | Gaurab Samanta Geoffrey Oxberry Antony N. Beris Robert Handler Kostas Housiadas |
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| Affiliation: | 1. Department of Chemical engineering, University of Delaware, USA;2. Department of Chemical Engineering, Massachusetts Institute of Technology, USA;3. Naval Research Laboratory, Washington DC, USA;4. Department of Mathematics, University of Aegean, Samos, Greece |
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| Abstract: | Earlier work [1, 2], using Karhunen-Loeve (K-L) analysis, demonstrated a dramatic enhancement of the importance of large scale motions with increased viscoelasticity and an equally dramatic decrease in the K-L dimension of the flow (an order of magnitude) as viscoelasticity increases versus similar Newtonian results. In this work we look into dynamics of viscoelastic turbulent flows by projecting the DNS data in time into a selected set of K-L modes. The dynamics of the coherent structures embedded in turbulent flows were investigated through calculations of mode auto and cross correlations. This allows for a more systematic examination of the role of large-scale structures in turbulence and drag reduction. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) |
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