Numerical Simulation of Oscillatory Marangoni Flow in Encapsulated Liquid Bridge

2005 ◽  
Author(s):  
Lan Peng ◽  
You-Rong Li ◽  
Nobuyuki Imaishi ◽  
Dan-Ling Zeng ◽  
Qing-Hua Chen
Keyword(s):  
Liquid Bridge ◽  
Marangoni Number ◽  
Oscillatory Flow ◽  
Marangoni Convection ◽  
Silicone Oil ◽  
Temperature Fields ◽  
Critical Conditions ◽  
Simulation Results ◽  
Physical And Mathematical Models ◽  
Oscillation Frequencies

The physical and mathematical models of the Marangoni convection of KF-96 silicone oil and FC-70 fluorinart in an encapsulated liquid bridge were established. To contrast to this configuration, the Marangoni convection of KF-96 silicone oil in a liquid bridge was also studied in present work. We conducted a series of unsteady two-dimensional numerical simulations. Simulation conditions correspond to those in the experiments of Majima and Kawamura (2001). The simulation results with large Marangoni number (Ma) predicted oscillatory flows under microgravity. The critical conditions for the onset oscillatory flow were determined and compared with the experimental results. Details of the flow and temperature fields were discussed. Oscillation frequencies were also exhibited.

Thermocapillary Convection of Low Prandtl Number Fluid in a Shallow Cylindrical Pool

2006 ◽  
Author(s):  
Fang Ling ◽  
You-Rong Li ◽  
Peng Lan ◽  
Shuang-Ying Wu ◽  
Qing-Hua Chen
Keyword(s):  
Prandtl Number ◽  
Marangoni Number ◽  
Oscillatory Flow ◽  
Thermocapillary Convection ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Critical Conditions ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Oscillation Frequencies

In order to understand the characteristics of thermocapillary convection, we conducted a series of unsteady three-dimensional numerical simulations of thermocapillary convection of low Prandtl number fluid in a shallow cylindrical pool with an azimuthal nonuniform temperature, an adiabatic solid bottom and free surface. The simulation results indicate that thermocapillary convection is steady three-dimensional flow at the small Marangoni number. But when Marangoni number exceeds some critical value, the flow will undergo a transition to oscillatory three-dimensional flow. The critical conditions for the onset of oscillatory flow are determined. Details of the flow and temperature fields are discussed, and oscillation frequencies are also exhibited.

Thermocapillary flow regimes and instability caused by a gas stream along the interface

2013 ◽  
Vol 714 ◽  
pp. 644-670 ◽  
Author(s):  
V. Shevtsova ◽  
Y. A. Gaponenko ◽  
A. Nepomnyashchy
Keyword(s):  
Marangoni Number ◽  
Gas Flow ◽  
Marangoni Convection ◽  
Silicone Oil ◽  
Numerical Study ◽  
Axial Direction ◽  
Horizontal Layer ◽  
Thermocapillary Flow ◽  
Instability Mechanism ◽  
Cold Side

AbstractWe present the results of a numerical study of the thermocapillary (Marangoni) convection in a liquid bridge of $\mathit{Pr}= 12$ ($n$-decane) and $\mathit{Pr}= 68$ (5 cSt silicone oil) when the interface is subjected to an axial gas stream. The gas flow is co- or counter-directed with respect to the Marangoni flow. In the case when the gas stream comes from the cold side, it cools down the interface to a temperature lower than that of the liquid beneath and in a certain region of the parameter space that cooling causes an instability due to a temperature difference in the direction perpendicular to the interface. The disturbances are swept by the thermocapillary flow to the cold side, which leads to the appearance of axisymmetric waves propagating in the axial direction from the hot to cold side. The mechanism of this new two-dimensional oscillatory instability is similar to that of the Pearson’s instability of the rest state in a thin layer heated from below (Pearson, J. Fluid Mech., vol. 4, 1958, p. 489), and it appears at the value of the transverse Marangoni number ${ \mathit{Ma}}_{\perp }^{cr} \approx 39\text{{\ndash}} 44$ lower than that of the Pearson’s instability in a horizontal layer ($48\lt { \mathit{Ma}}_{\perp }^{cr} \lt 80$, depending on the Biot number). The generality of the instability mechanism indicates that it is not limited to cylindrical geometry and might be observed in a liquid layer with cold gas stream.

Experimental and Numerical Analyses of the Flow and Temperature of Buoyancy-Marangoni Convection in a Liquid

2018 ◽  
Vol 880 ◽  
pp. 27-32
Author(s):  
Masakazu Haga ◽  
Tsuyoshi Kondo ◽  
Takayuki Hamauchi
Keyword(s):  
Numerical Calculation ◽  
Liquid Layer ◽  
Oscillatory Flow ◽  
Marangoni Convection ◽  
Silicone Oil ◽  
Experimental Result ◽  
Visualization Experiment ◽  
Buoyancy Convection ◽  
Calculation Results ◽  
Acceleration And Deceleration

Flow patterns and temperature distributions of buoyancy–Marangoni convection in a liquid were analyzed both experimentally and theoretically. We focused on two-dimensional natural convection in a horizontal liquid layer. In the experiment, silicone oil (with a viscosity of 1 × 10−5 m2/s) was used as a test liquid and the temperature and velocity fields were visualized using liquid crystal capsules. The visualization experiment included cases of both steady flow and oscillatory flow. In the case of a deep liquid layer, an oscillatory flow with repeated acceleration and deceleration occurred due to the interaction of the buoyancy convection and the Marangoni convection; however, this did not occur when the liquid layer was shallow. In the numerical calculation, the governing equations of buoyancy–Marangoni convection were solved using a finite difference method. The numerical calculation results demonstrate that the position of the downward flow due to buoyancy convection was changed by the Marangoni convection, which agreed with the experimental result.

scholarly journals Interfacial Contamination Caused by Water on Marangoni Convection in a Silicone Oil Liquid Bridge.

1993 ◽  
Vol 26 (6) ◽  
pp. 754-756 ◽  
Author(s):  
Akira Hirata ◽  
Shin-ichi Nishizawa ◽  
Masato Sakurai ◽  
Nobuyuki Imaishi
Keyword(s):  
Liquid Bridge ◽  
Marangoni Convection ◽  
Silicone Oil

Numerical Analysis of Marangoni Convection in Liquid Bridge With Liquid Encapsulation: Effect of Temperature Coefficient of Tension

2006 ◽  
Author(s):  
Lan Peng ◽  
Yourong Li ◽  
Juanfang Liu ◽  
Tien-Chien Jen ◽  
Qinghua Chen
Keyword(s):  
Surface Tension ◽  
Numerical Analysis ◽  
Finite Difference ◽  
Temperature Coefficient ◽  
Liquid Bridge ◽  
Function Method ◽  
Marangoni Convection ◽  
Effect Of Temperature ◽  
Interface Tension ◽  
Physical And Mathematical Models

The physical and mathematical models of the Marangoni convection in liquid bridge with liquid encapsulation (two immiscible coaxial liquid columns) were established. With these models a series of numerical simulations of the Marangoni convection in liquid bridge with liquid encapsulation have been performed by the vorticity-stream function method and the Alternative Direction Implicit scheme in finite difference. The distributions of temperature and flow in liquid columns were then obtained. In this paper, it is mainly considered that the ratio of the temperature coefficient of interface tension to surface tension affects on the Marangoni convection in liquid bridge with liquid encapsulation.

scholarly journals The Relative Contribution of Solutal Marangoni Convection to Thermal Marangoni Flow Instabilities in a Liquid Bridge of Smaller Aspect Ratios under Zero Gravity

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 116
Author(s):  
Radeesha Laknath Agampodi Mendis ◽  
Atsushi Sekimoto ◽  
Yasunori Okano ◽  
Hisashi Minakuchi ◽  
Sadik Dost
Keyword(s):  
Liquid Bridge ◽  
Marangoni Number ◽  
Marangoni Convection ◽  
Wave Mode ◽  
Dynamic Mode Decomposition ◽  
Flow Instabilities ◽  
Dynamic Mode ◽  
Zone Model ◽  
Zero Gravity ◽  
Aspect Ratios

The effect of solutal Marangoni convection on flow instabilities in the presence of thermal Marangoni convection in a Si-Ge liquid bridge with different aspect ratios As has been investigated by three-dimensional (3D) numerical simulations under zero gravity. We consider a half-zone model of a liquid bridge between a cold (top plane) and a hot (bottom plane) disks. The highest Si concentration is on the top of the liquid bridge. The aspect ratio (As) drastically affects the critical Marangoni numbers: the critical solutal Marangoni number (under small thermal Marangoni numbers (MaTAs≲1800)) has the same dependence on As as the critical thermal Marangoni number (under small solutal Marangoni numbers (400≲MaCAs≲800)), i.e., it decreases with increasing As. The azimuthal wavenumber of the traveling wave mode increases as decreasing As, i.e., larger azimuthal wavenumbers (m=6,7,11,12, and 13) appear for As=0.25, and only m=2 appears when As is one and larger. The oscillatory modes of the hydro waves have been extracted as the spatiotemporal structures by using dynamic mode decomposition (DMD). The present study suggests a proper parameter region of quiescent steady flow suitable for crystal growth for smaller aspect ratios of the liquid bridge.

scholarly journals Particle Accumulation Structures in a 5 cSt Silicone Oil Liquid Bridge: New Data for the Preparation of the JEREMI Experiment

2021 ◽  
Vol 33 (2) ◽  
Author(s):  
Paolo Capobianchi ◽  
Marcello Lappa
Keyword(s):  
Liquid Bridge ◽  
Silicone Oil ◽  
Fluid Dynamic ◽  
Solid Particles ◽  
Critical Threshold ◽  
Marangoni Flow ◽  
Disk Radius ◽  
Carrier Fluid ◽  
Aspect Ratios ◽  
Time Periodic

AbstractSystems of solid particles in suspension driven by a time-periodic flow tend to create structures in the carrier fluid that are reminiscent of highly regular geometrical items. Within such a line of inquiry, the present study provides numerical results in support of the space experiments JEREMI (Japanese and European Research Experiment on Marangoni flow Instabilities) planned for execution onboard the International Space Station. The problem is tackled by solving the unsteady non-linear governing equations for the same conditions that will be established in space (microgravity, 5 cSt silicone oil and different aspect ratios of the liquid bridge). The results reveal that for a fixed supporting disk radius, the dynamics are deeply influenced by the height of the liquid column. In addition to its expected link with the critical threshold for the onset of instability (which makes Marangoni flow time-periodic), this geometrical parameter can have a significant impact on the emerging waveform and therefore the topology of particle structures. While for shallow liquid bridges, pulsating flows are the preferred mode of convection, for tall floating columns the dominant outcome is represented by rotating fluid-dynamic disturbance. In the former situation, particles self-organize in circular sectors bounded internally by regions of particle depletion, whereas in the latter case, particles are forced to accumulate in a spiral-like structure. The properties of some of these particle attractors have rarely been observed in earlier studies concerned with fluids characterized by smaller values of the Prandtl number.

Finite Element Simulation of Laser Beam Welding Induced Residual Stresses and Distortions in a T-Joint Configuration for Aeronautic Structures

2009 ◽  
Author(s):  
Muhammad Zain-ul-abdein ◽  
Daniel Ne´lias ◽  
Jean-Franc¸ois Jullien ◽  
Dominique Deloison
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Laser Beam ◽  
Boundary Conditions ◽  
Laser Beam Welding ◽  
Temperature Fields ◽  
Heat Transfer Analysis ◽  
Small Scale ◽  
Joint Configuration ◽  
Simulation Results

Laser beam welding has found its application in the aircraft industry for the fabrication of fuselage panels in a T-joint configuration. However, the inconveniences like distortions and residual stresses are inevitable consequences of welding. The effort is made in this work to experimentally measure and numerically simulate the distortions induced by laser beam welding of a T-joint with industrially used thermal and mechanical boundary conditions on the thin sheets of aluminium 6056-T4. Several small scale experiments were carried out with various instrumentations to establish a database necessary to verify the simulation results. Finite element (FE) simulation is performed with Abaqus and the conical heat source is programmed in FORTRAN. Heat transfer analysis is performed to achieve the required weld pool geometry and temperature fields. Mechanical analysis is then performed with industrial loading and boundary conditions so as to predict the distortion and the residual stress pattern. A good agreement is found amongst the experimental and simulation results.

Oscillatory Natural Convection of a Liquid Metal in Circular Cylinders

1994 ◽  
Vol 116 (3) ◽  
pp. 627-632 ◽  
Author(s):  
Y. Kamotani ◽  
F.-B. Weng ◽  
S. Ostrach ◽  
J. Platt
Keyword(s):  
Experimental Study ◽  
Natural Convection ◽  
Liquid Metal ◽  
Oscillatory Flow ◽  
Circular Cylinders ◽  
Flow Structures ◽  
Supercritical Flow ◽  
Aspect Ratios ◽  
Oscillation Frequencies ◽  
Rayleigh Numbers

An experimental study is made of natural convection oscillations in gallium melts enclosed by right circular cylinders with differentially heated end walls. Cases heated from below are examined for angles of inclination (φ) ranging from 0 deg (vertical) to 75 deg with aspect ratios Ar (height/diameter) of 2, 3, and 4. Temperature measurements are made along the circumference of the cylinder to detect the oscillations, from which the oscillatory flow structures are inferred. The critical Rayleigh numbers and oscillation frequencies are determined. For Ar=3 and φ = 0 deg, 30 deg the supercritical flow structures are discussed in detail.

Surface Temperature Field Statistics at an Air/Water Interface for Grid-Generated Sub-Surface Turbulence

2002 ◽  
Author(s):  
Karen A. Flack ◽  
Geoffrey B. Smith
Keyword(s):  
Surface Temperature ◽  
Infrared Camera ◽  
Temperature Fields ◽  
Interface Temperature ◽  
Water Interface ◽  
Bulk Fluid ◽  
Air Water Interface ◽  
Evaporative Convection ◽  
The Difference ◽  
Oscillation Frequencies

Surface temperature fields and statistics are presented for the case of sub-surface grid-generated turbulence impacting an air/water interface. Temperature measurements are obtained with an infrared camera, sensitive in the 3–5 micron wavelength range. Results indicate that increased grid oscillation frequencies, and shallower grid depths, lead to increased surface mixing, yielding lower values of RMS temperature. Non-dimensionalization of the RMS temperatures using the difference in the average surface and the bulk fluid temperatures, collapses the data obtained for different grid depths and oscillation frequencies. This scaling is related to the thermal boundary layer thickness. The results are compared to the baseline case of turbulence due to evaporative convection without an oscillating grid.

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