Experimental assessment of fractal scale similarity in turbulent flows. Part 3. Multifractal scaling

Richard D. Frederiksen, Werner Dahm, David R. Dowling

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

Earlier experimental assessments of fractal scale similarity in geometric properties of turbulent flows are extended to assess the applicability of multifractal scale-similarity in the conserved scalar field ζ(x, t) and in the true scalar energy dissipation rate field ∇ζ·∇ζ(x, t). Fully resolved four-dimensional spatio-temporal measurements from a turbulent flow at Reλ ≈ 41 and Reδ ≈ 3000 are analysed. The utility of various classical constructs for identifying multifractal scale similarity in data records of finite length is examined. An objective statistical criterion based on the maximum allowable scale-to-scale variation L1(ε) in multiplier distributions <P(Mε)> obtained from multifractal gauge fields is developed to allow accurate discrimination between multifractal and non-multifractal scaling in finite-length experimental data records. Results from analyses of temporal intersections show that for scales greater than 0.03 λv/u, corresponding to 1.4 λD/u, the scalar dissipation field clearly demonstrates a scale-invariant similarity consistent with a multiplicative cascade process that can be modelled with a bilinear multiplier distribution. However, the conserved scalar field from precisely the same data does not follow any scale similarity consistent with a multiplicative cascade at scales below 0.5 λv/u. At larger scales, there are indications of a possible scale-invariant similarity in the scalar field, but with a fundamentally different multiplier distribution.

Original languageEnglish (US)
Pages (from-to)127-155
Number of pages29
JournalJournal of Fluid Mechanics
Volume338
StatePublished - May 10 1997
Externally publishedYes

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Fractals
turbulent flow
Turbulent flow
fractals
scaling
Gages
Energy dissipation
scalars
multipliers
cascades
intersections
discrimination
indication
dissipation
energy dissipation

ASJC Scopus subject areas

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

Cite this

Experimental assessment of fractal scale similarity in turbulent flows. Part 3. Multifractal scaling. / Frederiksen, Richard D.; Dahm, Werner; Dowling, David R.

In: Journal of Fluid Mechanics, Vol. 338, 10.05.1997, p. 127-155.

Research output: Contribution to journalArticle

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