Oscillatory Maxwell Cattaneo ferroconvection in A Viscoelastic Magnetic Fluid Saturated porous Medium

Abstract

Theoretical investigation of the convective instability of a Boussinesq viscoelastic ferrofluid saturating a porous medium heated from below under the influence of constraints such as Maxwell-Cattaneo law, anisotropic porous medium and rotation is presented in the thesis. Darcy and Darcy-Brinkman law are employed to describe the fluid motion. The work reported in the thesis is primarily based on analytical approach which makes use of the linear stability analysis and the normal mode technique. The problems investigated in the thesis find intensive applications in fields such as chemical engineering, geothermal energy devices, nuclear reactors, oil reservoirs, polymer industries, crystal growth, solidification of molten alloys, bio-mechanics, food processing and production of pure medication and so on. With this motivation, we have investigated six problems in the thesis. The brief summary of each problem is given below. Oscillatory Maxwell-Cattaneo Ferroconvection in a densely packed porous medium saturated with a viscoelastic magnetic fluid newlineThe combined effect of viscoelasticity and second sound on the onset of ferroconvection in a densely packed porous medium is examined by considering the Oldroyd-B model and by resorting to the classical stability analysis. A generalized Darcy model is employed as the momentum equation to take into account the viscoelastic properties and the Maxwell-Cattaneo heat flux law is applied to take into account the non-classical heat conduction. Considering the boundary conditions appropriate for an analytical approach, the critical values pertaining to both stationary and oscillatory instabilities are obtained by means of the normal mode analysis. Oscillatory convection is the preferred mode of instability due to the presence of viscoelastic parameters as well as the Cattaneo effect. It is shown that oscillatory porous medium ferroconvection is advanced through the magnetic forces, nonlinearity in magnetization, stress relaxation due to viscoelasticity, Vadasz number ...