Meniscus of a ferrofluid around a vertical cylindrical wire carrying electric current

Abstract

We study the meniscus profiles of ferrofluids in the magnetic field of a vertical current-carrying wire. Measurements of the free ferrofluid surface profile are quantitatively compared with numerical calculations. The theoretical model leads to a second-order ordinary differential equation. All material parameters are determined in independent experiments, therefore no fitting parameters are involved in the calculations. The experimental results can be modeled by the equilibrium of magnetic, gravitational, and interface tension forces. The classical model that neglects interface tension yields significant deviations from the experimental profiles in the parameter range studied.

System of particles with shifted magnetic dipoles

“…The numerical calculations are made with the commercial software package AN-SYS FLUENT using the finite volume method for the two phases fluid and air. The domain of calculation is a rectangle with a width of 16 mm and a height of 7 mm according to the experimental setup in [6], where the origin is shifted by 2 mm in the vertical direction by the thickness of the layer of magnetic fluid, see Fig. 2(bottom).…”

“…Since the experiments were performed with the fluid EMG 909, we use the following standard set of material parameters: ρ = 0.20 kg/m 3 , σ = 0.0258 N m −1 and χ = 0.61 [6]. The question of the used dynamical viscosity is referred to Sec.…”

“…More than two decades later, the renewed interest started with a numerical work [5] on the resulting nonlinear differential equation describing the evolution of the surface ξ(r) as a function of the distance r from the wire and taking the surface tension into account. Recently, experimental data has been published [6], which allows a comparison with the calculated results. Therefore, the aim of this paper is to present the numerical simulation of the underlying Navier-Stokes equation for an axially symmetrical, i.e.…”

Azimuthal field instability in a confined ferrofluid

“…Since the seminal work of Ref. [10] investigators have carried out theoretical and experimental studies in order to determine the precise shape of the curved meniscus in both the absence and presence of surface tension effects [11][12][13][14]. Interestingly, * eduardodias @ df.…”

Wetting of ferrofluids: Phenomena and control

“…This has been treated as analogous to the wetting transition caused by van der Waals forces [50]. The same phenomenon with different boundary conditions has since been studied extensively using more sophisticated numerical models, also very recently [51], [52]. Similar magnetic field induced changes in spreading have also been investigated experimentally on vertical walls [53], nanochannels [54], porous media [55], and in the cases of thin films [56], [57] and droplets [35]- [38].…”