Marangoni Convection inWater-Isopropanol Mixtures in the Presence of Soret Effect

2011 ◽  
Vol 38 (4) ◽  
pp. 312-327
Author(s):  
Mohammad Azizur Rahman ◽  
M. Ziad Saghir
Keyword(s):  
Marangoni Convection ◽  
Soret Effect

Longwave Marangoni convection in a surfactant solution between poorly conducting boundaries

2013 ◽  
Vol 718 ◽  
pp. 428-456 ◽  
Author(s):  
Sergey Shklyaev ◽  
Alexander A. Nepomnyashchy
Keyword(s):  
Physical Mechanism ◽  
Marangoni Convection ◽  
Soret Effect ◽  
Surfactant Solution ◽  
Sorption Kinetics ◽  
Heated Layer ◽  
Surface Phase ◽  
Amplitude Equations ◽  
Weakly Nonlinear ◽  
Ill Posed

AbstractWe consider Marangoni convection in a heated layer of a binary liquid. The solute is a surfactant, which is present in both surface and bulk phases; the bulk gradient of the concentration is formed due to the Soret effect. Linear stability analysis demonstrates a well-pronounced stabilization of the layer due to the adsorption kinetics and advection of the surface phase. We derive nonlinear amplitude equations for longwave perturbations in the case of fast sorption kinetics (small Langmuir number) and demonstrate that with increase in the effect of the adsorption, subcritical excitation occurs. In the case of a finite Langmuir number, the weakly nonlinear problem is ill-posed. A physical mechanism of subcritical bifurcation is discussed.

scholarly journals Marangoni convection in binary mixtures with Soret effect

1998 ◽  
Vol 375 ◽  
pp. 143-177 ◽  
Author(s):  
A. BERGEON ◽  
D. HENRY ◽  
H. BENHADID ◽  
L. S. TUCKERMAN
Keyword(s):  
Marangoni Convection ◽  
Soret Effect ◽  
Spectral Element ◽  
Soret Coefficient ◽  
Small Range ◽  
Concentration Gradients ◽  
Time Stepping ◽  
Pure Fluid ◽  
Secondary Bifurcations ◽  
Steady Convection

Marangoni convection in a differentially heated binary mixture is studied numerically by continuation. The fluid is subject to the Soret effect and is contained in a two-dimensional small-aspect-ratio rectangular cavity with one undeformable free surface. Either or both of the temperature and concentration gradients may be destabilizing; all three possibilities are considered. A spectral-element time-stepping code is adapted to calculate bifurcation points and solution branches via Newton's method. Linear thresholds are compared to those obtained for a pure fluid. It is found that for large enough Soret coefficient, convection is initiated predominantly by solutal effects and leads to a single large roll. Computed bifurcation diagrams show a marked transition from a weakly convective Soret regime to a strongly convective Marangoni regime when the threshold for pure fluid thermal convection is passed. The presence of many secondary bifurcations means that the mode of convection at the onset of instability is often observed only over a small range of Marangoni number. In particular, two-roll states with up-flow at the centre succeed one-roll states via a well-defined sequence of bifurcations. When convection is oscillatory at onset, the limit cycle is quickly destroyed by a global (infinite-period) bifurcation leading to subcritical steady convection.

scholarly journals Thermo-solutal convection with Soret effect

2021 ◽  
Author(s):  
Md. Abdur Rahman
Keyword(s):  
Porous Layer ◽  
Liquid Layer ◽  
Marangoni Convection ◽  
Stokes Equations ◽  
Soret Effect ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Solutal Convection ◽  
Buoyancy Convection

In the present study, the onset of thermal convection in a liquid layer overlying a porous layer where the whole system is being laterally heated is investigated. The non-linear two-dimensional Navier Stokes equations, the energy equation, the mass balance equation and the continuity equation are solved for the liquid layer. Instead of the Navier Stokes equations, the Brinkman model is used for the porous layer. The partial differential equations are solved numerically using the finite element technique. A two-dimensional geometrical model with lateral heating is considered. Two different cases are analyzed in this thesis. In the first case, the gravity driven buoyancy convection and the Marangoni convection are studied. For the Marangoni convection, the microgravity condition is considered and the surface tension is assumed to vary linearly with temperature. Different aspect ratios, as well as thickness ratios, are studies in detail for both the buoyancy and the Marangoni convection. Results revealed that for both the buoyancy and the Marangoni cases, flow penetrates into the porous layer, only when the thickness ratio is more than 0.90. In the case of thermo-solutal convection in the presence of Soret effect, it has been found that the isopropanol component goes either towards the hot or the cold walls depending on the fluid mixtures which has been used in the system.

Darcy-Benard double diffusive Marangoni convection with Soret effect in a composite layer system

2020 ◽  
Vol 8 (4) ◽  
pp. 1473-1479
Author(s):  
Sumithra R. ◽  
Komala B. ◽  
Manjunatha N.
Keyword(s):  
Marangoni Convection ◽  
Soret Effect ◽  
Composite Layer ◽  
Layer System ◽  
Double Diffusive

Marangoni Convection in Water Isopropanol Mixture in the Presence of Soret Effect

2011 ◽  
Author(s):  
M. A. Rahman ◽  
M. Z. Saghir
Keyword(s):  
Layer Thickness ◽  
Porous Layer ◽  
Liquid Layer ◽  
Convective Flow ◽  
Marangoni Convection ◽  
Soret Effect ◽  
Cold Wall ◽  
First Case ◽  
Liquid Layer Thickness

In the present study, the onset of Marangoni convection in a liquid layer overlaying a porous layer where the whole system is being laterally heated is investigated. Two different cases are analyzed in this paper. In the first case, the Marangoni convection in the absence of the Soret effect is studied. Results revealed, when the liquid layer and the porous layer have identical thickness, the convective flow remains in the liquid layer. However, the flow covers the entire cavity when the liquid layer thickness is very small (less than 1/10th of the porous layer). For the case of Marangoni convection in the presence of Soret effect, it has been found that the isopropanol component enriches near the cold wall.

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