Rayleigh-Benard convection

experimental study of time-dependent instabilities

B. Martinet, Ronald Adrian

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

The transition from steady thermal convection to turbulent thermal convection in a horizontal layer of water (Prandtl number=5.8) contained by a square cavity of large aspect ratio (48.5) has been studied using laser Doppler velocimetry. Power spectra of the horizontal velocity fluctuations were measured in the Rayleigh number range from 30,000 and 99,000, wherein periodic, quasi-periodic, and broad-band time-dependent instabilities coexist. At Rayleigh numbers greater than 32,000 a narrow-band spectrum emerges. The frequency of this motion scales with x/d2 modified by a Prandtl number factor for intermediate values of the Prandtl number. Between 10 Racand 30 Raithe frequency undergoes three abrupt jumps while increasing along an Ra2/3 power law. A different frequency mode that occurs above 30 Racappears to be associated with fully turbulent convection.

Original languageEnglish (US)
Pages (from-to)316-322
Number of pages7
JournalExperiments in Fluids
Volume6
Issue number5
DOIs
StatePublished - Jan 1988
Externally publishedYes

Fingerprint

Rayleigh-Benard convection
Prandtl number
Rayleigh number
free convection
Power spectrum
Velocity measurement
narrowband
power spectra
aspect ratio
Aspect ratio
convection
broadband
cavities
Water
Lasers
water
lasers
Convection
Hot Temperature

ASJC Scopus subject areas

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

Cite this

Rayleigh-Benard convection : experimental study of time-dependent instabilities. / Martinet, B.; Adrian, Ronald.

In: Experiments in Fluids, Vol. 6, No. 5, 01.1988, p. 316-322.

Research output: Contribution to journalArticle

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