An Analysis of Spin-Diffusion Dominated Ferrofluid Spin-Up Flows in Uniform Rotating Magnetic Fields

S. Khushrushahi[1], A. Guerrero[2], C. Rinaldi[3], and M. Zahn[1]
[1]Massachusetts Institute of Technology, Cambridge, MA
[2]Univeridad Industrial de Santander, Bucaramanga, Colombia
[3]University of Puerto Rico, Mayaguez, Mayaguez, PR
Published in 2011

This work analyzes the spin-diffusion dominated explanation for spin-up bulk flows in ferrofluid filled cylinders, with no free surface, subjected to a uniform rotating magnetic field. COMSOL results are compared to experimental results and analytical results.

Simulating ferrofluid spin-up flows have many subtleties, especially when using a single domain region to model the ferrofluid cylinder without correct adjustment for demagnetizing effects. Both one (ferrofluid cylinder) and two domain (ferrofluid cylinder in air) problems solved in this work are compared and give exact results.

Overall, this work documents the exact method of simulating such flows in COMSOL by benchmarking results with analytical solutions and experimental results.