Convective motion concentration at the boundaries of a horizontal fluid layer with inhomogeneous unstable temperature gradient along the height

1976 ◽  
Vol 10 (5) ◽  
pp. 745-750 ◽  
Author(s):  
A. V. Getling
Keyword(s):  
Temperature Gradient ◽  
Fluid Layer ◽  
Convective Motion ◽  
Horizontal Fluid Layer ◽  
Unstable Temperature

Effect of Phase Thermal Modulation Without Stationary Temperature Gradient on the Threshold of Convection

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
K. Souhar ◽  
S. Aniss
Keyword(s):  
Temperature Gradient ◽  
Convective Instability ◽  
Stable Equilibrium ◽  
Equilibrium Configuration ◽  
Fluid Layer ◽  
Dimensionless Frequency ◽  
Time Varying ◽  
Horizontal Fluid Layer ◽  
Stationary Component ◽  
Good Agreement

The convective instability of a horizontal fluid layer subject to a time varying gradient of temperature is investigated. The stationary component of the temperature gradient is considered equal to zero and the oscillating components imposed on the horizontal boundaries are in phase and with the same amplitude. The aim of the present paper is to examine the effect of this type of modulation on the onset of convective instability. We show that unlike the case where the equilibrium configuration is stable in the absence of modulation, we have instability when the temperature at the horizontal boundaries is modulated in phase. Also, we observe that in the limit of low and high dimensionless frequency of modulation, ω < 0.5 and ω > 140, the basic state tends to a stable equilibrium configuration and for an intermediate dimensionless frequency, the system is potentially unstable. The results obtained from analytical asymptotic study for low and high dimensionless frequency are in good agreement with the numerical ones.

Effect of Modulation on Rayleigh-Benard Convection-II

2003 ◽  
Vol 58 (2-3) ◽  
pp. 176-182
Author(s):  
B. S. Bhadauria
Keyword(s):  
Rayleigh Number ◽  
Temperature Gradient ◽  
Fluid Layer ◽  
Critical Rayleigh Number ◽  
Periodic Part ◽  
Prandtl Numbers ◽  
Rigid Walls ◽  
Rayleigh Benard Convection ◽  
Rayleigh Benard ◽  
Horizontal Fluid Layer

The linear stability of a horizontal fluid layer, confined between two rigid walls, heated from below and cooled from above is considered. The temperature gradient between the walls consists of a steady part and a periodic part that oscillates with time. Only infinitesimal disturbances are considered. Numerical results for the critical Rayleigh number are obtained for various Prandtl numbers and for various values of the frequency. Some comparisons with known results have also been made.

Onset of thermal convection in a horizontal fluid layer under ramp heating

2002 ◽  
Author(s):  
Dae Jun Yang ◽  
Jake Kim ◽  
Chang Kyun Choi ◽  
In Gook Hwang
Keyword(s):  
Thermal Convection ◽  
Fluid Layer ◽  
Horizontal Fluid Layer
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