Group 6

Nonlinear Dynamical Analysis of Ferrofluid

Ferrofluids exibit nonlinear dynamical behavior in response to both static and oscillating external magnetic fields. An experiment will be developed to isolate a single peak response of ferrofluid to an electromagnetic field generated by a hertzien coil. The apparatus will be configured such that a single peak will be isolated. The response will be observed with a high-speed camera. First a static magnetic field will be applied. This is expected to result in nonlinear surface behavior accompanied by a hysteresis effect. Spontaneous peak formation will be observed at a critical field magnitude. We will examine this response and relate an established qualitative model. A critical magnitude in which spontaneous peak formation is induced (normal field instability), will be observed and analytically correlated to the model. The expected subcritical instability will be observed and the resulting peaks peak characteristics will be analyzed. Next, a thermal component will be introduced and a corresponding term added to the dynamical equation to account for this effect. This nonlinear surface oscillating bifurcation is rarely studied or observed.

Experimental Apparatus

Parts list

1. Hertzion Coil
2. Teflon Fluid Holder
3. Power Supply
4. High-speed Camera
5. Ferrofluid - EFH-1

Experimental Procedure

References

T. Mahr and I. Rehberg, "Nonlinear dynamics of a single ferrofluid-peak in an oscillating magnetic field," Physica D, vol. 111, pp. 335-346, Jan 1998.