Prakash R

A linear stability analysis of thermal convection in variable viscosity Newtonian ferromagnetic liquid by considering all possible boundary combinations is studied. The importance of this problem lies in the interesting possibility of regulating convection using heat source (sink). Using Galerkin technique the critical eigenvalue and wave number for stationary convection are obtained. These critical values are then improved upon by the shooting method. The influence of various parameters on the onset of convection has been analyzed. � 2017, Springer India Pvt. Ltd.

A linear stability analysis of buoyancy and surface tension driven convection in temperature and magnetic field sensitive Newtonian ferromagnetic liquid is studied. The importance of this problem lies in the interesting possibility of regulating convection using a heat source (sink). The problem discussed in this paper leads to a situation that the basic temperature gradient here is non-uniform. The governing equations thereby are of variable coefficients. The principle of exchange of stabilities is shown to be valid. The critical values are obtained using higher order Galerkin technique. The influence of various magnetic and nonmagnetic parameters on the onset of convection has been analyzed. It is found that there is tight coupling between Rayleigh and Marangoni numbers, with an increase in one resulting in a decrease in the other. Variable viscosity parameter and heat source destabilize the system. The effect of heat sink is to stabilize the system. Buoyancy magnetization parameter destabilizes the system both in presence/absence of heat source/sink. Copyright � 2013 by ASME.

The effect of surface tension and vertical throughflow in magnetic field and temperature sensitive liquid of Newtonian ferromagnetic type is examined. Combining shooting and Galerkin techniques the stationary critical eigenvalues are computed. On the ferroconvection onset, M3, non-buoyancy magnetic parameter and Pr (>1), Prandtl number have no influence. For upward or downward directions dual effect of destabilizing or stabilizing the system is observed in the presence of vertical throughflow. Throughflow effect studied through Pe, Peclet number delays ferroconvection onset and is observed to be independent to flow direction. M1, the magnetic buoyancy number, and V, the variable viscosity parameters have destabilizing influences on the system. Ferrofluids being fascinating materials are used as constant agents for magnetic resonance imaging (MRI). The great variety of magnetic fluids are tailored for technological, biological, medical and material science applications. � The Electrochemical Society