Large-scale, coherent structures in wide-aspect-ratio, turbulent, Rayleigh-benard convection

P. J. Sakievich, Yulia Peet, Ronald Adrian

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Investigation of the spatial organization of large-scale, coherent structures in turbulent, Rayleigh-Bénard convection is performed through direct numerical simulation. The simulation is performed in a 6.3 aspect ratio cell with a Rayleigh number of 9.6 × 107 and Prandtl number equal to 6.7. Single and double point statistics are compared against experimental results and are found to be in excellent agreement. Large-scale mean thermals with coherence times exceeding 10 eddy-turnovers are discovered and these mean thermals are found to be a reliable tool for identifying and interpreting the large, velocity roll-cells. Our simulations show an existence of a large-scale coherent pattern that consists of three major velocity roll-cells, two of which are semi-toroidal, or horse-shoe shaped, that are connected to the side-walls, and the third roll-cell lies across the center of the cell between the semi-toroidal cells. We present the possible formation mechanism of this nearly-periodic structure, observed at intermediate scales of averaging, as a perturbation from a perfectly periodic, crystal-like, pattern. The dynamics of these structures are evaluated using short-time averages.

Original languageEnglish (US)
Title of host publication9th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2015
PublisherTSFP-9
Volume2
ISBN (Electronic)9780000000002
StatePublished - Jan 1 2015
Event9th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2015 - Melbourne, Australia
Duration: Jun 30 2015Jul 3 2015

Other

Other9th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2015
CountryAustralia
CityMelbourne
Period6/30/157/3/15

Fingerprint

Aspect ratio
Periodic structures
Prandtl number
Direct numerical simulation
Statistics
Crystals
Hot Temperature
Convection

ASJC Scopus subject areas

  • Fluid Flow and Transfer Processes

Cite this

Sakievich, P. J., Peet, Y., & Adrian, R. (2015). Large-scale, coherent structures in wide-aspect-ratio, turbulent, Rayleigh-benard convection. In 9th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2015 (Vol. 2). TSFP-9.

Large-scale, coherent structures in wide-aspect-ratio, turbulent, Rayleigh-benard convection. / Sakievich, P. J.; Peet, Yulia; Adrian, Ronald.

9th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2015. Vol. 2 TSFP-9, 2015.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Sakievich, PJ, Peet, Y & Adrian, R 2015, Large-scale, coherent structures in wide-aspect-ratio, turbulent, Rayleigh-benard convection. in 9th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2015. vol. 2, TSFP-9, 9th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2015, Melbourne, Australia, 6/30/15.
Sakievich PJ, Peet Y, Adrian R. Large-scale, coherent structures in wide-aspect-ratio, turbulent, Rayleigh-benard convection. In 9th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2015. Vol. 2. TSFP-9. 2015
Sakievich, P. J. ; Peet, Yulia ; Adrian, Ronald. / Large-scale, coherent structures in wide-aspect-ratio, turbulent, Rayleigh-benard convection. 9th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2015. Vol. 2 TSFP-9, 2015.
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