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.

scholarly journals The effect of uniform magnetic field on spatial-temporal evolution of thermocapillary convection with the silicon oil based ferrofluid

2020 ◽  
Vol 24 (6 Part B) ◽  
pp. 4159-4171
Author(s):  
Shuo Yang ◽  
Rui Ma ◽  
Qiaosheng Deng ◽  
Guofeng Wang ◽  
Yu Gao ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Free Surface ◽  
Transverse Magnetic Field ◽  
Liquid Bridge ◽  
Thermocapillary Convection ◽  
Surface Deformation ◽  
Axial Magnetic Field ◽  
Transverse Magnetic ◽  
Surface Flow ◽  
Silicon Oil

A uniform axial or transverse magnetic field is applied on the silicon oil based ferrofluid of high Prandtl number fluid (Pr ? 111.67), and the effect of magnetic field on the thermocapillary convection is investigated. It is shown that the location of vortex core of thermocapillary convection is mainly near the free surface of liquid bridge due to the inhibition of the axial magnetic field. A velocity stagnation region is formed inside the liquid bridge under the axial magnetic field (B = 0.3-0.5 T). The disturbance of bulk reflux and surface flow is suppressed by the increasing axial magnetic field. There is a dynamic response of free surface deformation to the axial magnetic field, and then the contact angle variation of the free surface at the hot corner is as following, ?hot, B = 0.5 T = 83.34? > ?hot, B = 0.3 T = 72.16? > > ?hot,B = 0.1 T = 54.21? > ?hot, B = 0 T = 43.33?. The results show that temperature distribution near the free surface is less and less affected by thermocapillary convection with the increasing magnetic field, and it presents a characteristic of heat-conduction. In addition, the transverse magnetic field does not realize the fundamental inhibition for thermocapillary convection, but it transfers the influence of thermocapillary convection to the free surface.

Effect of Marangoni number on thermocapillary convection and free-surface deformation in liquid bridges

2016 ◽  
Vol 25 (2) ◽  
pp. 178-187 ◽  
Author(s):  
Yin Zhang ◽  
Hu-Lin Huang ◽  
Xiao-Ming Zhou ◽  
Gui-Ping Zhu ◽  
Yong Zou
Keyword(s):  
Free Surface ◽  
Marangoni Number ◽  
Thermocapillary Convection ◽  
Surface Deformation ◽  
Liquid Bridges ◽  
Free Surface Deformation

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.

Thermocapillary Convection in a Floating Half Zone

2012 ◽  
Vol 248 ◽  
pp. 218-223
Author(s):  
Ru Quan Liang ◽  
Wen Jun Duan ◽  
Guang Dong Duan ◽  
Ja Ba
Keyword(s):  
Free Surface ◽  
Liquid Bridge ◽  
Surface Deformation ◽  
Stokes Equations ◽  
Ambient Air ◽  
Conservation Equation ◽  
Staggered Grid ◽  
Relative Pressure ◽  
External Vibration ◽  
Free Surface Deformation

A numerical simulation has been conducted to investigate the effect of the external vibration referred to as g-jitter on the marangoni convection in liquid bridge of high Pr number fluid by taking both the dynamic free surface deformation and ambient air effects into consideration. The Navier-Stokes equations coupled with the energy conservation equation are solved on a staggered grid, and the free surface deformation is captured by introducing the mass conserving level set approach. The pressure distributions within the liquid bridge under external vibrations were investigated, and the results show that the pressure in liquid bridge presents periodic oscillation under external vibration. The closer to the hot disk, the greater the relative pressure value is. Moreover, the surface deformation and the surface amplitude under external vibration were investigated as well.

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