### Abstract

We investigate large Rayleigh number (10^{6}-10^{9}) and large Prandtl number (10^{2}-10^{3}) thermal convection in glycerol in an aspect ration one cubic cell. The kinematic viscosity of the fluid strongly depends upon the temperature. The symmetry between the top and bottom boundary layers is thus broken, the so-called non-Boussinesq regime. In a previous paper Wu and Libchaber have proposed that in such a state the two thermal boundary layers adjust their length scales so that the mean hot and cold temperature fluctuations are equal in the center of the cell. We confirm this equality. A simplified two-dimensional model for the mean center temperature based on an equation for the thermal boundary layer is presented and compared with the experimental results. The conclusion is that the central temperature adjusts itself so that heat fluxes from boundaries are equal, temperature fluctuations at the center symmetrical, at a cost of very different temperature drops and Rayleigh number for each boundary.

Original language | English (US) |
---|---|

Pages (from-to) | 1034-1042 |

Number of pages | 9 |

Journal | Physics of Fluids |

Volume | 9 |

Issue number | 4 |

State | Published - Apr 1997 |

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### ASJC Scopus subject areas

- Fluid Flow and Transfer Processes
- Computational Mechanics
- Mechanics of Materials
- Physics and Astronomy(all)
- Condensed Matter Physics

### Cite this

*Physics of Fluids*,

*9*(4), 1034-1042.

**Non-Boussinesq effect : Thermal convection with broken symmetry.** / Zhang, Jun; Childress, Stephen; Libchaber, Albert.

Research output: Contribution to journal › Article

*Physics of Fluids*, vol. 9, no. 4, pp. 1034-1042.

}

TY - JOUR

T1 - Non-Boussinesq effect

T2 - Thermal convection with broken symmetry

AU - Zhang, Jun

AU - Childress, Stephen

AU - Libchaber, Albert

PY - 1997/4

Y1 - 1997/4

N2 - We investigate large Rayleigh number (106-109) and large Prandtl number (102-103) thermal convection in glycerol in an aspect ration one cubic cell. The kinematic viscosity of the fluid strongly depends upon the temperature. The symmetry between the top and bottom boundary layers is thus broken, the so-called non-Boussinesq regime. In a previous paper Wu and Libchaber have proposed that in such a state the two thermal boundary layers adjust their length scales so that the mean hot and cold temperature fluctuations are equal in the center of the cell. We confirm this equality. A simplified two-dimensional model for the mean center temperature based on an equation for the thermal boundary layer is presented and compared with the experimental results. The conclusion is that the central temperature adjusts itself so that heat fluxes from boundaries are equal, temperature fluctuations at the center symmetrical, at a cost of very different temperature drops and Rayleigh number for each boundary.

AB - We investigate large Rayleigh number (106-109) and large Prandtl number (102-103) thermal convection in glycerol in an aspect ration one cubic cell. The kinematic viscosity of the fluid strongly depends upon the temperature. The symmetry between the top and bottom boundary layers is thus broken, the so-called non-Boussinesq regime. In a previous paper Wu and Libchaber have proposed that in such a state the two thermal boundary layers adjust their length scales so that the mean hot and cold temperature fluctuations are equal in the center of the cell. We confirm this equality. A simplified two-dimensional model for the mean center temperature based on an equation for the thermal boundary layer is presented and compared with the experimental results. The conclusion is that the central temperature adjusts itself so that heat fluxes from boundaries are equal, temperature fluctuations at the center symmetrical, at a cost of very different temperature drops and Rayleigh number for each boundary.

UR - http://www.scopus.com/inward/record.url?scp=0001247944&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0001247944&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0001247944

VL - 9

SP - 1034

EP - 1042

JO - Physics of Fluids

JF - Physics of Fluids

SN - 1070-6631

IS - 4

ER -