Flow Visualization and Pattern Dynamics in Be´nard-Marangoni Convection

2006 ◽  
Author(s):  
Samir Rahal ◽  
Hisao Azuma
Keyword(s):  
Free Surface ◽  
Aspect Ratio ◽  
Prandtl Number ◽  
Surface Deformation ◽  
Marangoni Convection ◽  
Temperature Fields ◽  
Pattern Dynamics ◽  
Free Surface Deformation ◽  
Prandtl Numbers ◽  
Biot Numbers

The aim of this experimental work is to study the pattern dynamics in the Be´nard-Marangoni convection. The free surface deformation fields were visualized by interferometry and the temperature fields by infrared thermography. The influence of the aspect ratio, Rayleigh, Biot and Prandtl numbers, was considered. More dynamics are found to be induced by increasing the Biot number. Conversely, increasing the Prandtl number reduces the dynamics. The deformation magnitude and the wavenumber increase as functions of the gradient of temperature. Two behaviours of the deformation, as a function of Prandtl and Biot numbers, were observed, depending on the value of the gradient of temperature.

Influence of Ambient Airflow on Free Surface Deformation and Flow Pattern Inside Liquid Bridge With Large Prandtl Number Fluid (Pr > 100) Under Gravity

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Shuo Yang ◽  
Ruquan Liang ◽  
Song Xiao ◽  
Jicheng He ◽  
Shuo Zhang
Keyword(s):  
Free Surface ◽  
Prandtl Number ◽  
Liquid Bridge ◽  
Thermocapillary Convection ◽  
Surface Deformation ◽  
Flow Cell ◽  
Thermocapillary Force ◽  
Flow Cells ◽  
Lower Disk ◽  
Free Surface Deformation

The influence of airflow shear on the free surface deformation and the flow structure for large Prandtl number fluid (Pr = 111.67) has been analyzed numerically as the parallel airflow shear is induced into the surrounding of liquid bridge from the lower disk or the upper disk. Contrasted with former studies, an improved level set method is adopted to track any tiny deformation of free surface, where the area compensation is carried out to compensate the nonconservation of mass. Present results indicate that the airflow shear can excite flow cells in the isothermal liquid bridge. The airflow shear induced from the upper disk impulses the convex region of free interface as the airflow shear intensity is increased, which may exceed the breaking limit of liquid bridge. The free surface is transformed from the “S”-shape into the “M”-shape as the airflow shear is induced from the lower disk. For the nonisothermal liquid bridge, the flow cell is dominated by the thermocapillary convection at the hot corner if the airflow shear comes from the hot disk, and another reversed flow cell near the cold disk appears. While the shape of free surface depends on the competition between the thermocapillary force and the shear force when the airflow is induced from the cold disk.

Thermosolutocapillary Convection in an Open Rectangular Cavity With Dynamic Free Surface

2015 ◽  
Vol 137 (8) ◽  
Author(s):  
Xiaoming Zhou ◽  
Xiulan Huai
Keyword(s):  
Free Surface ◽  
Aspect Ratio ◽  
Capillary Number ◽  
Marangoni Number ◽  
Surface Deformation ◽  
Central Zone ◽  
Deformation Mode ◽  
Rectangular Cavity ◽  
Left Wall ◽  
Free Surface Deformation

Thermosolutocapillary convection within a rectangular cavity with dynamic free surface is numerically investigated in the absence of gravitational effects. Both the temperature and solute concentration gradients are applied horizontally. The free surface deformation is captured by the level set method. Two cases of the ratio of thermal to solutal Marangoni number Rσ < −1 and Rσ = −1 are considered. For Rσ < −1, the free surface bulges out near the left wall and bulges in near the right wall; with the increase of Marangoni number, the free surface deformation decreases and with the increase of capillary number and aspect ratio, it increases. For Rσ = −1, the free surface bulges out near the left and right walls and bulges in at the central zone; with the increase of Marangoni number, the free surface deformation mode is changed and with the increase of capillary number and aspect ratio, the free surface deformation increases.

Free-surface deformation measurement

1997 ◽  
Author(s):  
H. Stahl ◽  
Kevin Stultz ◽  
H. Stahl ◽  
Kevin Stultz
Keyword(s):  
Free Surface ◽  
Surface Deformation ◽  
Deformation Measurement ◽  
Free Surface Deformation
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