Numerical treatment of free surface problems in ferrohydrodynamics

Lavrova, O. A.; Matthies, Gunar; Mitkova, Teodora; Полевиков, В. К.; Tobiska, Lutz

doi:10.1088/0953-8984/18/38/s09

Cited by 61 publications

(63 citation statements)

References 18 publications

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“…The numerical study of a nonlinearly polarizable ferrofluid drop showed similar behaviour to linearly polarizable drops at low magnetic field strengths when drop deformations were not substantial . Lavrova et al (2004Lavrova et al ( , 2006) also considered nonlinearly magnetizable ferrofluid drops and used a finite element method in which the governing equations of the magnetic liquid were coupled by the force balance at the interface and the surface tension was applied as a boundary condition at the interface. Their numerical results of drop equilibrium shapes were in accordance with the theory of Bacri & Salin (1982).…”

Section: Introductionmentioning

confidence: 99%

“…At sufficiently high fields, shape transitions such as conical tips may occur (Bacri & Salin 1982;Stone, Lister & Brenner 1999;Lavrova et al 2006). Our numerical algorithm to handle such regimes includes modifications to the discretization scheme for the magnetic stress tensor and the averaging scheme for the magnetic fluid properties, within the framework already detailed elsewhere (Afkhami et al 2008a).…”

Section: Introductionmentioning

confidence: 99%

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Deformation of a hydrophobic ferrofluid droplet suspended in a viscous medium under uniform magnetic fields

et al. 2010

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The effect of applied magnetic fields on the deformation of a biocompatible hydrophobic ferrofluid drop suspended in a viscous medium is investigated numerically and compared with experimental data. A numerical formulation for the time-dependent simulation of magnetohydrodynamics of two immiscible non-conducting fluids is used with a volume-of-fluid scheme for fully deformable interfaces. Analytical formulae for ellipsoidal drops and near-spheroidal drops are reviewed and developed for code validation. At low magnetic fields, both the experimental and numerical results follow the asymptotic small deformation theory. The value of interfacial tension is deduced from an optimal fit of a numerically simulated shape with the experimentally obtained drop shape, and appears to be a constant for low applied magnetic fields. At high magnetic fields, on the other hand, experimental measurements deviate from numerical results if a constant interfacial tension is implemented. The difference can be represented as a dependence of apparent interfacial tension on the magnetic field. This idea is investigated computationally by varying the interfacial tension as a function of the applied magnetic field and by comparing the drop shapes with experimental data until a perfect match is found. This estimation method provides a consistent correlation for the variation in interfacial tension at high magnetic fields. A conclusion section provides a discussion of physical effects which may influence the microstructure and contribute to the reported observations.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Deformation of a hydrophobic ferrofluid droplet suspended in a viscous medium under uniform magnetic fields

et al. 2010

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“…The mathematical formulation for hydrodynamics of ferrofluid was discussed by Rosensweig (1985). The deformation of a freely suspended droplet and a sessile droplet in a uniform magnetic field was previously numerically studied by coupling the magnetic field, the free surface, and the fluid flow (Lavrova et al 2006;Sero-Guillaume et al 1992). The stable shape is determined by the interaction between magnetic force and the interfacial tension force.…”

Section: Introductionmentioning

confidence: 99%

Numerical and experimental investigations of the formation process of ferrofluid droplets

Liu

Tan

Yap

et al. 2011

Microfluid Nanofluid

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This paper reports both experimental and numerical investigations of the formation process of ferrofluid droplets in a flow focusing configuration with and without an applied magnetic field. In the experiment, the homogenous magnetic field was generated using an electromagnet. The magnetic field in the flow direction affects the formation process and changes the size of the droplets. The change in the droplet size depends on the magnetic field strength and the flow rates. A numerical model was used to investigate the force balance during the droplet breakup process. A linearly magnetizable fluid was assumed. Particle level set method was employed to capture the interface movement between the continuous fluid and the dispersed fluid. Results of the droplet formation process and the flow field are discussed for both cases with and without the magnetic field. Finally, experimental and numerical results are compared.

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“…In every step of the outer iteration the mesh is adapted by Laplace smoothing. The nonlinear magnetization is handled by a fixpoint iteration, see [1], which requires 8 − 10 iterations in this case.…”

Section: Magnetostatic Problemmentioning

confidence: 99%