Detection of Lagrangian coherent structures in three-dimensional turbulence

M. A. Green, C. W. Rowley, G. Haller

Research output: Contribution to journalArticle

233 Scopus citations

Abstract

We use direct Lyapunov exponents (DLE) to identify Lagrangian coherent structures in two different three-dimensional flows, including a single isolated hairpin vortex, and a fully developed turbulent flow. These results are compared with commonly used Eulerian criteria for coherent vortices. We find that despite additional computational cost, the DLE method has several advantages over Eulerian methods, including greater detail and the ability to define structure boundaries without relying on a preselected threshold. As a further advantage, the DLE method requires no velocity derivatives, which are often too noisy to be useful in the study of a turbulent flow. We study the evolution of a single hairpin vortex into a packet of similar structures, and show that the birth of a secondary vortex corresponds to a loss of hyperbolicity of the Lagrangian coherent structures.

Original languageEnglish (US)
Pages (from-to)111-120
Number of pages10
JournalJournal of Fluid Mechanics
Volume572
DOIs
StatePublished - Feb 1 2007
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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