Stretching in a model of a turbulent flow

Baggaley, A.W., Barenghi, C.F. and Shukurov, A. (2009) Stretching in a model of a turbulent flow. Physica D: Nonlinear Phenomena, 238(4), pp. 365-369. (doi: 10.1016/j.physd.2008.10.013)

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Using a multi-scaled, chaotic flow known as the KS model of turbulence [J.C.H. Fung, J.C.R. Hunt, A. Malik, R.J. Perkins, Kinematic simulation of homogeneous turbulence by unsteady random fourier modes, J. Fluid Mech. 236 (1992) 281–318], we investigate the dependence of Lyapunov exponents on various characteristics of the flow. We show that the KS model yields a power law relation between the Reynolds number and the maximum Lyapunov exponent, which is similar to that for a turbulent flow with the same energy spectrum. Our results show that the Lyapunov exponents are sensitive to the advection of small eddies by large eddies, which can be explained by considering the Lagrangian correlation time of the smallest scales. We also relate the number of stagnation points within a flow to the maximum Lyapunov exponent, and suggest a linear dependence between the two characteristics.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Baggaley, Dr Andrew
Authors: Baggaley, A.W., Barenghi, C.F., and Shukurov, A.
Subjects:Q Science > QC Physics
College/School:College of Science and Engineering > School of Mathematics and Statistics > Mathematics
Journal Name:Physica D: Nonlinear Phenomena
Published Online:12 November 2008

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