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Dynamic K‐L analysis of coherent structures based on DNS of turbulent Newtonian and viscoelastic flows (Poster Presentation)
Author(s) -
Samanta Gaurab,
Oxberry Geoffrey,
Beris Antony N.,
Handler Robert,
Housiadas Kostas
Publication year - 2007
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.200701120
Subject(s) - viscoelasticity , turbulence , drag , newtonian fluid , scale (ratio) , flow (mathematics) , mechanics , physics , work (physics) , dimension (graph theory) , non newtonian fluid , statistical physics , classical mechanics , mathematics , thermodynamics , quantum mechanics , pure mathematics
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)