Visualization of temperature fields and double-diffusive convection using liquid crystals in an aqueous solution crystallizing along a vertical wall

1992 ◽  
Vol 12-12 (4-5) ◽  
pp. 245-250 ◽  
Author(s):  
T. Nishimura ◽  
M. Fujiwara ◽  
H. Miyashita
Keyword(s):  
Aqueous Solution ◽  
Liquid Crystals ◽  
Vertical Wall ◽  
Temperature Fields ◽  
Double Diffusive Convection ◽  
Diffusive Convection ◽  
Double Diffusive

Numerical Study of the Onset of Double-Diffusive Cellular Convection Due to a Uniform Lateral Heat Flux

1982 ◽  
Vol 104 (4) ◽  
pp. 649-655 ◽  
Author(s):  
S. Takao ◽  
M. Tsuchiya ◽  
U. Narusawa
Keyword(s):  
Heat Flux ◽  
Numerical Study ◽  
Vertical Wall ◽  
Lewis Number ◽  
Double Diffusive Convection ◽  
Physical Experiments ◽  
Diffusive Convection ◽  
The Stability ◽  
Double Diffusive ◽  
Lateral Heat

When a fluid with a vertical solute gradient of (−dS/dy)0 is heated laterally, roll cells start to form at the boundary, developing into a series of convective layers. Numerical experiments were performed to investigate the onset of the abovementioned double-diffusive convection under the application of a uniform lateral heat flux. The paper reports the results and discussion of the following aspects of the stability of double-diffusive convection; (i) the relationship between the critical value, (Ra/Rs)c, above which convection cells form along the vertical wall and the nondimensional slot width, (d/L), (ii) the effect of the Lewis number on (Ra/Rs)c. It was also confirmed that values of (Ra/Rs)c as well as H/L (the nondimensional vertical size of incipient cells) obtained in this numerical experiment for wide slot widths (d/L>∼30), agreed well with those obtained previously by physical experiments.

Numerical Study of Double Diffusive Convection within the Annular Region of Two Concentric Vertical Cylinders

2017 ◽  
Vol 374 ◽  
pp. 1-17 ◽  
Author(s):  
Mohamed Amine Medebber ◽  
Nourddine Retiel
Keyword(s):  
Numerical Study ◽  
Vertical Wall ◽  
Annular Region ◽  
Geometrical Parameters ◽  
Double Diffusive Convection ◽  
Uniform Temperature ◽  
Simpler Algorithm ◽  
Diffusive Convection ◽  
Vertical Cylinders ◽  
Double Diffusive

This article reports a numerical study of double-diffusive convection within the annular region of two concentric vertical cylinders. The outer vertical wall is maintained at lower uniform temperature and concentration, while the inner vertical wall is maintained at higher uniform temperature and concentration. The top and bottom horizontal walls are adiabatic and impermeable to mass transfer. The resulting governing equations are solved using a finite volume method. The coupling between the continuity and momentum equations is solved using the SIMPLER algorithm. The compilations have been obtained for Prandtl numbers (Pr) equal to 7.0, and Lewis number (Le) equal to 100. The thermal Rayleigh number (RaT) and height ratio (X) are, respectively, varied in the range 103≤RaT≤106 and 0.0≤X≤1.0. The influence of physical and geometrical parameters on the streamlines, isotherms, isoconcentrations, average Nusselt and Sherwood numbers has been numerically investigated in detail.

Liquid-Liquid Mixing Due to G-Jitter in Microgravity

2002 ◽  
Author(s):  
C. Benjapiyaporn ◽  
V. Timchenko ◽  
S. S. Leong ◽  
G. de Vahl Davis ◽  
E. Leonardi
Keyword(s):  
Numerical Simulation ◽  
Vertical Wall ◽  
Double Diffusive Convection ◽  
Low Gravity ◽  
Diffusive Convection ◽  
Higher Temperature ◽  
Miscible Liquids ◽  
Range Of Values ◽  
Buoyancy Ratio ◽  
Double Diffusive

This paper describes a study of double diffusive convection inside a rectangular cavity in low gravity; it arose out of a much broader study of solidification of a binary alloy in microgravity. The cavity initially contained two different but miscible liquids meeting at a sharp vertical interface at the middle of a cavity. One vertical wall was kept at a uniform low temperature, while the opposite wall was at a uniform higher temperature. The top and bottom walls were adiabatic. All walls were impermeable. A numerical simulation was made of the induced convection and mixing for a range of values of buoyancy ratio and gravity characteristics, including both steady g and g-jitter.

scholarly journals Double-diffusive Convection in a Two Layered Aqueous Solution by Lateral Heating and Cooling.

2000 ◽  
Vol 26 (4) ◽  
pp. 604-608 ◽  
Author(s):  
TAKESHI YAMANE ◽  
EIJI NAKAJIMA ◽  
MASAMICHI YOSHIDA ◽  
HISASHI MIYASHITA
Keyword(s):  
Aqueous Solution ◽  
Double Diffusive Convection ◽  
Lateral Heating ◽  
Heating And Cooling ◽  
Diffusive Convection ◽  
Double Diffusive

Large-scale Langmuir circulation and double-diffusive convection: evolution equations and flow transitions

1994 ◽  
Vol 276 ◽  
pp. 189-210 ◽  
Author(s):  
Stephen M. Cox ◽  
Sidney Leibovich
Keyword(s):  
Boundary Conditions ◽  
Large Scale ◽  
Evolution Equations ◽  
Mixed Boundary ◽  
Travelling Waves ◽  
Temperature Fields ◽  
Double Diffusive Convection ◽  
Langmuir Circulation ◽  
Diffusive Convection ◽  
Double Diffusive

Two-dimensional Langmuir circulation in a layer of stably stratified water and the mathematically analogous problem of double-diffusive convection are studied with mixed boundary conditions. When the Biot numbers that occur in the mechanical boundary conditions are small and the destabilizing factors are large enough, the system will be unstable to perturbations of large horizontal length. The instability may be either direct or oscillatory depending on the control parameters. Evolution equations are derived here to account for both cases and for the transition between them. These evolution equations are not limited to small disturbances of the nonconvective basic velocity and temperature fields, provided the spatial variations in the horizontal remain small. The direct bifurcation may be supercritical or subcritical, while in the case of oscillatory motions, stable finite-amplitude travelling waves emerge. At the transition, travelling waves, standing waves, and modulated travelling waves all are stable in sub-regimes.

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