Modal decomposition of velocity signals in a plane, turbulent wake

B. Marasli, H. Champagne, Israel J Wygnanski

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

The Orr Sommerfeld equation admits two solution modes for the two-dimensional plane wake. These are the sinuous mode with antisymmetric streamwise fluctuations and the varicose mode with symmetric streamwise fluctuations. The varicose mode is often ignored because its amplification rates are considerably less than those of the sinuous mode. An experimental investigation of the varicose mode in a two-dimensional turbulent wake was undertaken to determine if this mode of instability agrees as well with linear stability theory, as did the sinuous mode in previous experiments (Wygnanski, Champagne & Marasli 1986). The experiments demonstrated that, although it is possible to generate a nearly pure symmetric disturbance wave, it is very difficult to do, because the flow is very sensitive to the slightest asymmetries which might be present in the experiments. These asymmetries are preferentially amplified, resulting in the eventual distortion of an initially prominent symmetric wave.

Original languageEnglish (US)
Pages (from-to)255-273
Number of pages19
JournalJournal of Fluid Mechanics
Volume198
StatePublished - Jan 1989

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turbulent wakes
Decomposition
decomposition
Experiments
Amplification
Orr-Sommerfeld equations
asymmetry
wakes
disturbances

ASJC Scopus subject areas

  • Computational Mechanics
  • Mechanics of Materials
  • Physics and Astronomy(all)
  • Condensed Matter Physics

Cite this

Modal decomposition of velocity signals in a plane, turbulent wake. / Marasli, B.; Champagne, H.; Wygnanski, Israel J.

In: Journal of Fluid Mechanics, Vol. 198, 01.1989, p. 255-273.

Research output: Contribution to journalArticle

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