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Motaghian M, Shirsavar R, Erfanifam M, Sabouhi M, van der Linden E, Stone HA, Bonn D, Habibi M. Rapid Spreading of a Droplet on a Thin Soap Film. Langmuir 2019; 35:14855-14860. [PMID: 31644302 PMCID: PMC6868707 DOI: 10.1021/acs.langmuir.9b02274] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 10/19/2019] [Indexed: 05/30/2023]
Abstract
We study the spreading of a droplet of surfactant solution on a thin suspended soap film as a function of dynamic surface tension and volume of the droplet. Radial growth of the leading edge (R) shows power-law dependence on time with exponents ranging roughly from 0.1 to 1 for different surface tension differences (Δσ) between the film and the droplet. When the surface tension of the droplet is lower than the surface tension of the film (Δσ > 0), we observe rapid spreading of the droplet with R ≈ tα, where α (0.4 < α < 1) is highly dependent on Δσ. Balance arguments assuming the spreading process is driven by Marangoni stresses versus inertial stresses yield α = 2/3. When the surface tension difference does not favor spreading (Δσ < 0), spreading still occurs but is slow with 0.1 < α < 0.2. This phenomenon could be used for stretching droplets in 2D and modifying thin suspended films.
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Affiliation(s)
- M. Motaghian
- Physics
and Physical Chemistry of Foods, Wageningen
University, Wageningen 6708 PB, Gelderland, The Netherlands
| | - R. Shirsavar
- Department
of Physics, Faculty of Science, University
of Zanjan, Zanjan 45371-38791, Zanjan, Iran
| | - M. Erfanifam
- Department
of Physics, Faculty of Science, University
of Zanjan, Zanjan 45371-38791, Zanjan, Iran
| | - M. Sabouhi
- Department
of Physics, Faculty of Science, University
of Zanjan, Zanjan 45371-38791, Zanjan, Iran
| | - E. van der Linden
- Physics
and Physical Chemistry of Foods, Wageningen
University, Wageningen 6708 PB, Gelderland, The Netherlands
| | - H. A. Stone
- Department
of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - D. Bonn
- Institute
of Physics, van der Waals-Zeeman Institute, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, North Holland, The Netherlands
| | - Mehdi Habibi
- Physics
and Physical Chemistry of Foods, Wageningen
University, Wageningen 6708 PB, Gelderland, The Netherlands
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Mollaei S, Nasiri M, Soltanmohammadi N, Shirsavar R, Ramos A, Amjadi A. Soap-film flow induced by electric fields in asymmetric frames. Phys Rev E 2018; 97:043110. [PMID: 29758613 DOI: 10.1103/physreve.97.043110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Indexed: 11/07/2022]
Abstract
Net fluid flow of soap films induced by (ac or dc) electric fields in asymmetric frames is presented. Previous experiments of controllable soap film flow required the simultaneous use of an electrical current passing through the film and an external electric field or the use of nonuniform ac electric fields. Here a single voltage difference generates both the electrical current going through the film and the electric field that actuates on the charge induced on the film. The film is set into global motion due to the broken symmetry that appears by the use of asymmetric frames. If symmetric frames are used, the film flow is not steady but time dependent and irregular. Finally, we study numerically these film flows by employing the model of charge induction in ohmic liquids.
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Affiliation(s)
- S Mollaei
- Department of Physics, Faculty of Science, University of Zanjan, Zanjan P.O. Box 45371-38791, Iran
| | - M Nasiri
- Department of Physics, Faculty of Science, University of Zanjan, Zanjan P.O. Box 45371-38791, Iran
| | - N Soltanmohammadi
- Department of Physics, Faculty of Science, University of Zanjan, Zanjan P.O. Box 45371-38791, Iran
| | - R Shirsavar
- Department of Physics, Faculty of Science, University of Zanjan, Zanjan P.O. Box 45371-38791, Iran and Department of Physics, Sharif University of Technology, Tehran P.O. Box 11365-9161, Iran
| | - A Ramos
- Departamento de Electrónica y Electromagnetismo, Facultad de Física, Universidad de Sevilla, Seville 41012, Spain
| | - A Amjadi
- Department of Physics, Sharif University of Technology, Tehran P.O. Box 11365-9161, Iran
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Nasiri M, Shirsavar R, Mollaei S, Ramos A. Numerical study of soap-film flow by nonuniform alternating electric fields. Phys Rev E 2017; 95:022806. [PMID: 28297867 DOI: 10.1103/physreve.95.022806] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Indexed: 11/07/2022]
Abstract
Fluid flow of suspended liquid films induced by non-uniform alternating electric fields has been reported. The electric fields were generated by two rod-like electrodes perpendicular to the fluid surface. The observed fluid flow was explained qualitatively by considering a charge induction mechanism, where the electric field actuates on the charge induced on the film surface. In this paper we perform a numerical study of this fluid flow taking into account the charge induction mechanism. The numerical results are compared with experiments and good agreement is found. Finally, we propose the application of the device as a new kind of two dimensional fluid pump.
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Affiliation(s)
- M Nasiri
- Department of Physics, Faculty of Science, University of Zanjan, Zanjan, Iran
| | - R Shirsavar
- Department of Physics, Faculty of Science, University of Zanjan, Zanjan, Iran
| | - S Mollaei
- Department of Physics, Faculty of Science, University of Zanjan, Zanjan, Iran
| | - A Ramos
- Departamento de Electrónica y Electromagnetismo, Facultad de Física, Universidad de Sevilla, Sevilla, Spain
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Shirsavar R, Nasiri M, Amjadi A, Nejati A, Sobhani SO, Habibi M. Rotation induced by uniform and non-uniform magnetic fields in a conducting fluid carrying an electric current. RSC Adv 2016. [DOI: 10.1039/c6ra24346k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
External magnetic field induces controllable rotation in a conducting fluid carrying an electric current.
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Affiliation(s)
- R. Shirsavar
- Department of Physics
- Faculty of Science
- University of Zanjan
- Zanjan
- Iran
| | - M. Nasiri
- Department of Physics
- Faculty of Science
- University of Zanjan
- Zanjan
- Iran
| | - A. Amjadi
- Department of Physics
- Sharif University of Technology
- Tehran
- Iran
| | - A. Nejati
- Physikalisches Institut and Bethe Center for Theoretical Physics
- Universität Bonn
- Germany
| | - S. O. Sobhani
- Department of Physics
- Sharif University of Technology
- Tehran
- Iran
- Department of Energy Engineering
| | - Mehdi Habibi
- Condensed Matter National Laboratory
- IPM
- Tehran
- Iran
- Institute of Physics
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