Scalar interfaces in digital images of turbulent flows

R. R. Prasad, K. R. Sreenivasan

Research output: Contribution to journalArticle

Abstract

A scalar interface is defined as the surface separating the scalar-marked regions of a turbulent flow from the rest. The problem of determining the two-dimensional intersections of scalar interfaces is examined, taking as a specific example digital images of an axisymmetric jet visualized by laser-induced fluorescence. The usefulness of gradient and Laplacian techniques for this purpose is assessed, and it is shown that setting a proper threshold on the pixel intensity works well if the signal/noise ratio is high. Two methods of determining the proper threshold are presented, and the results are discussed. As one application of the technique, the fractal dimension of the scalar interface is calculated.

Original languageEnglish (US)
Pages (from-to)259-264
Number of pages6
JournalExperiments in Fluids
Volume7
Issue number4
DOIs
StatePublished - Feb 1989

Fingerprint

Fractal dimension
turbulent flow
Turbulent flow
Pixels
Fluorescence
scalars
Lasers
thresholds
laser induced fluorescence
intersections
fractals
pixels
gradients

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Computational Mechanics
  • Fluid Flow and Transfer Processes

Cite this

Scalar interfaces in digital images of turbulent flows. / Prasad, R. R.; Sreenivasan, K. R.

In: Experiments in Fluids, Vol. 7, No. 4, 02.1989, p. 259-264.

Research output: Contribution to journalArticle

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