Laminar one-dimensional flow of a ferrosuspension in a varying magnetic field

M. M. Maiorov - A. O. Tsebers

Institute of Physics, Latvian Academy of Sciences, Salaspils-1, LV-2169, Latvia

Abstract
Nonstationary, one-dimensional flow of dilute ferrosuspensions is studied in a plane channel in a magnetic field varying in accordance with H = H₀cosωt. Consideration of internal rotations of the particles leads to the appearance of a variable component of the viscosity a cosωt (a < 1). The problem is solved by using a Laplace transform with respect to the variable τ = t+ (a/ω)sinωt. It is shown that for a given pressure drop, the intensity of the velocity oscillations over the channel cross section changes nonmonotonically; furthermore, the location of the maximum of the intensity pulsations shifts toward the channel wall as ω increases. The role of nonlinear distortions of an input signal is evaluated on the basis of an analysis of the first and second harmonics of the flow oscillations. In the case of a given flow rate, up to a frequency where it is still possible to neglect the finiteness of the propagation of elastic perturbations, the pressure oscillations reproduce the oscillations of the effective viscosity without distortion.