Anisotropy of the magnetoviscous effect in ferrofluids.

The anisotropy of the magnetoviscous effect in ferrofluids subjected to weak planar Couette flow is investigated by extensive molecular simulations. The field and concentration dependence of the viscosity coefficients are found to depend on the relative orientation of the magnetic field with respect to the flow geometry. Comparison with dynamical mean-field models shows satisfactory agreement for moderate interaction strengths. In the semidilute regime it is found that the anisotropy contains valuable information on particle interaction.