Three-dimensionalization of freely-decaying two-dimensional turbulence

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal

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Author(s)

Detail(s)

Original languageEnglish
Pages (from-to)2918-2932
Journal / PublicationPhysics of Fluids
Volume16
Issue number8
Publication statusPublished - Aug 2004
Externally publishedYes

Abstract

The three-dimensionalization of freely-decaying two-dimensional turbulence is studied numerically. Using two different basic states, it is shown that the hyperbolic instability of steady mixing layers generalizes to unsteady flow. The growth of three-dimensional (3D) perturbations is interpreted in terms of a "pressureless" analysis in which horizontal pressure gradients are neglected and the underlying physical mechanism is advective in nature. For a steady, pressureless base flow the (asymptotic) growth rate is exactly determined, in a few special cases, by variants of the so-called Weiss criterion; more generally, local growth rate estimates are obtained. For freely-decaying two-dimensional turbulence there is analogous behavior: while the 3D perturbation remains small the pressureless approximation holds at large horizontal scales and local growth rate estimates apply. The pressureless modes have a determining influence on the growth (the damping effect of the horizontal pressure gradient is small). © 2004 American Institute of Physics.

Citation Format(s)

Three-dimensionalization of freely-decaying two-dimensional turbulence. / Ngan, K.; Straub, D. N.; Bartello, P.

In: Physics of Fluids, Vol. 16, No. 8, 08.2004, p. 2918-2932.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal