Free-Surface Vibrations of a Magnetic Liquid

1972 ◽  
Vol 94 (1) ◽  
pp. 103-108 ◽  
Author(s):  
F. T. Dodge ◽  
L. R. Garza
Keyword(s):  
Magnetic Field ◽  
Free Surface ◽  
Magnetic Fluid ◽  
Magnetic Interaction ◽  
Surface Tension Force ◽  
Bond Number ◽  
Low Gravity ◽  
Fluid Sloshing ◽  
Apparent Reduction ◽  
Surface Vibrations

A theory of magnetic fluid sloshing in a solenoidal magnetic field is developed herein. It shows that (a) the free-surface waves on a magnetic fluid are dynamically similar to the waves on an ordinary liquid in a reduced gravity field, and (b) the apparent reduction in gravity depends on the strength of the applied magnetic field. But, a deviation from true low-gravity behavior occurs whenever the Bond number (ratio of effective gravitational force to surface tension force) is much smaller than 1.0. The deviation is caused by a magnetic interaction that induces a jump in pressure across the free surface. To verify the conclusions of the theory and to evaluate the usefulness of magnetic sloshing as a low-gravity sloshing simulation, an exploratory series of tests was conducted using a magnetic-colloid liquid and a large solenoidal electromagnet. Measured slosh natural frequencies agreed well with theory, but the measured slosh damping was larger than predicted by existing correlation equations.

scholarly journals Three-Dimensional Magnetic Fluid Boundary Layer Flow Over a Linearly Stretching Sheet

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
E. E. Tzirtzilakis ◽  
N. G. Kafoussias
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Magnetic Fluid ◽  
Boundary Layer Flow ◽  
Stretching Sheet ◽  
Numerical Technique ◽  
Three Dimensional ◽  
Magnetic Interaction ◽  
Layer Flow ◽  
The Magnetic Field

The three-dimensional laminar and steady boundary layer flow of an electrically nonconducting and incompressible magnetic fluid, with low Curie temperature and moderate saturation magnetization, over an elastic stretching sheet, is numerically studied. The fluid is subject to the magnetic field generated by an infinitely long, straight wire, carrying an electric current. The magnetic fluid far from the surface is at rest and at temperature greater of that of the sheet. It is also assumed that the magnetization of the fluid varies with the magnetic field strength H and the temperature T. The numerical solution of the coupled and nonlinear system of ordinary differential equations, resulting after the introduction of appropriate nondimensional variables, with its boundary conditions, describing the problem under consideration, is obtained by an efficient numerical technique based on the common finite difference method. Numerical calculations are carried out for the case of a representative water-based magnetic fluid and for specific values of the dimensionless parameters entering into the problem, and the obtained results are presented graphically for these values of the parameters. The analysis of these results showed that there is an interaction between the motions of the fluid, which are induced by the stretching surface and by the action of the magnetic field, and the flow field is noticeably affected by the variations in the magnetic interaction parameter β. The important results of the present analysis are summarized in Sec. 6.

Relation between Dynamic Pressure and Displacement of Free Surface in Two-Layer Sloshing between a Magnetic Fluid and Silicone Oil

2014 ◽  
Vol 792 ◽  
pp. 33-38 ◽  
Author(s):  
Takayoshi Ishiyama ◽  
Shunsuke Kaneko ◽  
Shinichiro Takemoto ◽  
Tatsuo Sawada
Keyword(s):  
Magnetic Field ◽  
Free Surface ◽  
Magnetic Fluid ◽  
Silicone Oil ◽  
Dynamic Pressure ◽  
Pressure Change ◽  
Pressure Transducers ◽  
Presence And Absence

We performed experiments regarding two-layer sloshing, using a magnetic fluid and silicone oil, and measured the dynamic pressure change using pressure transducers. We also investigated displacements of the free surface by comparing it with the dynamic pressure, clarifying the relation between them, both in the presence and absence of a magnetic field.

Magnetic Fluid Bridge between Coaxial Cylinders with a Line Conductor in Case of Wetting

2015 ◽  
Vol 233-234 ◽  
pp. 335-338 ◽  
Author(s):  
Alexandra Vinogradova ◽  
Vera Naletova ◽  
Vladimir Turkov
Keyword(s):  
Magnetic Field ◽  
Free Surface ◽  
Analytical Solution ◽  
Magnetic Fluid ◽  
Axially Symmetric ◽  
Magnetic Liquid ◽  
Coaxial Cylinders ◽  
Straight Wire ◽  
A Current ◽  
Symmetric Shape

We consider a heavy, incompressible, homogenous, isothermal magnetic fluid between two coaxial cylinders in case of wetting. There is a current-carrying straight wire on the axis of these cylinders. The magnetic fluid is immersed in a non-magnetic liquid with the same density (the case of hydroimponderability). We apply the Langevin law to describe a magnetic fluid magnetization. Using the general analytical solution for any axially symmetric shape of the magnetic fluid free surface in any axisymmetric magnetic field, we investigate the break-up and the rebuilding of the magnetic fluid bridge in case of wetting.

The Perspectives of Magnetic Fluid Deformable Mirrors for Adaptive Optics Systems

2012 ◽  
Vol 485 ◽  
pp. 293-296
Author(s):  
Zhi Zheng Wu ◽  
Mei Liu
Keyword(s):  
Magnetic Field ◽  
Free Surface ◽  
Adaptive Optics ◽  
Magnetic Fluid ◽  
Applied Magnetic Field ◽  
Nano Particles ◽  
Deformable Mirrors ◽  
Working Principle ◽  
And Performance ◽  
Wavefront Correctors

Recently, magnetic fluid deformable mirrors (MFDMs) were proposed as a novel type of wavefront correctors for adaptice optics (AO) systems, which offer cost and performance advantages over existing wavefront correctors. These mirrors are developed by coating the free surface of a magnetic fluid with a thin reflective film of nano-particles. The reflective surface of the mirrors can be deformed using a locally applied magnetic field and thus serves as a wavefront corrector. In this paper, the working principle of MFDMs is first presented, then the perspectives of MFDMs that will have to be addressed before they can be finally used practically in AO applications are discussed.

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