Study of two elements constituting turbulence by a multifractal theory for probability density functions - Through the analyses of 4096 super(3) DNS

The probability density functions (PDFs) of energy dissipation rates created from the whole of the DNS region of the size 4096 super(3) (named whl-PDFs) for various sizes of coarse graining areas are analyzed by multifractal PDF theory (MPDFT). Furthermore, other PDFs named max-PDF and min-PDF for v...

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Bibliographic Details
Published in:Journal of physics. Conference series 2013-01, Vol.410, p.1-4
Main Authors: Arimitsu, T, Arimitsu, N, Takechi, K, Kaneda, Y, Ishihara, T
Format: Article
Language:English
Subjects:
Adjustment
Fluid dynamics
Fluid flow
Granulation
Probability density functions
Slopes
Turbulence
Turbulent flow
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Summary:The probability density functions (PDFs) of energy dissipation rates created from the whole of the DNS region of the size 4096 super(3) (named whl-PDFs) for various sizes of coarse graining areas are analyzed by multifractal PDF theory (MPDFT). Furthermore, other PDFs named max-PDF and min-PDF for various sizes of coarse graining areas, created respectively from the partial DNS regions of the size 512 super(3) with maximum and minimum enstrophy, are also analyzed by making use of the whl-PDF. It is shown that there is a whl-PDF with an appropriate size of coarse graining area, whose slope of the tail part, can adjust the slope of the tail-part of a max-PDF. On the other hand, there is a whl-PDF whose center part can adjust quite accurately the center part of a min-PDF. Note that the partial DNS region with maximum (minimum) enstrophy is the region of maximally dense (rare) vortexes, and therefore contributes mainly to the tail (center) part of the whl-PDF. It is found that these adjustments are systematic with respect to the sizes of coarse graining areas.
ISSN:1742-6588
1742-6596
DOI:10.1088/1742-6596/410/1/012083