Experimental study of temperature distribution and local heat flux for turbulent Rayleigh–Bénard convection of air in a long rectangular enclosure

2008 ◽  
Vol 51 (17-18) ◽  
pp. 4238-4248 ◽  
Author(s):  
Anna Ebert ◽  
Christian Resagk ◽  
André Thess
Keyword(s):  
Experimental Study ◽  
Heat Flux ◽  
Temperature Distribution ◽  
Local Heat ◽  
Rectangular Enclosure ◽  
Bénard Convection ◽  
Benard Convection ◽  
Local Heat Flux ◽  
Rayleigh Benard Convection ◽  
Rayleigh Benard

The effect of boundary properties on controlled Rayleigh–Bénard convection

2000 ◽  
Vol 411 ◽  
pp. 39-58 ◽  
Author(s):  
LAURENS E. HOWLE
Keyword(s):  
Heat Flux ◽  
Control Method ◽  
Lower Boundary ◽  
Bénard Convection ◽  
Benard Convection ◽  
Boundary Properties ◽  
Parameter Ranges ◽  
Differential Control ◽  
Rayleigh Benard Convection ◽  
Rayleigh Benard

We investigate the effect of the finite horizontal boundary properties on the critical Rayleigh and wave numbers for controlled Rayleigh–Bénard convection in an infinite horizontal domain. Specifically, we examine boundary thickness, thermal diffusivity and thermal conductivity. Our control method is through perturbation of the lower-boundary heat flux. A linear proportional-differential control method uses the local amplitude of a shadowgraph to actively redistribute the lower-boundary heat flux. Realistic boundary conditions for laboratory experiments are selected. Through linear stability analysis we examine, in turn, the important boundary properties and make predictions of the properties necessary for successful control experiments. A surprising finding of this work is that for certain realistic parameter ranges, one may find an isola to time-dependent convection as the primary bifurcation.

Experimental study of the velocity field in Rayleigh-Bénard convection

1978 ◽  
Vol 85 (4) ◽  
pp. 641-653 ◽  
Author(s):  
M. Dubois ◽  
P. Bergé
Keyword(s):  
Experimental Study ◽  
Velocity Field ◽  
Local Velocity ◽  
Velocity Measurements ◽  
Bénard Convection ◽  
Benard Convection ◽  
Theoretical Predictions ◽  
Rayleigh Benard Convection ◽  
Rayleigh Benard ◽  
Velocity Mode

Local velocity measurements performed in a convecting layer of fluid show that the velocity field can be described by a dominant fundamental velocity mode mixed with an increasing proportion of second and third harmonics as ε, the reduced distance to the convective thresholdRc, is increased from 0 to ∼ 10. The spatial and thermal dependences of the amplitudes of these different modes are reported and compared with theoretical predictions.

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