Response of magnetic fluids to mechanical, magnetic and thermal forces

We have studied the response of magnetic fluids to mechanical, magnetic and thermal forces in (i) steady rotation of a non-conducting sphere in a paramagnetic fluid (ii) paramagnetic fluid flow through an annulus with porous walls (iii) helical flow of ferrofluid with heat conduction. In the first two we are able to bring out the nature of interaction of magnetic and mechanical forces - the orienting influence of the flow on the dipoles, the subsequent modification in the dipole distribution, the interactions of applied magnetic field and magnetization and their effect on the velocity distribution. In the third problem we have analysed the magneto thermodynamics of magnetic fluids taking into account the viscous dissipation. Thermal conduction and energy dissipation act opposite to the cooling effect of magnetic field. The effect of magnetic field on pressure is to suppress its magnitude.