Optimal Stability Thresholds in Rotating Fully Anisotropic Porous Medium with LTNE

The onset of thermal convection in an anisotropic horizontal porous layer heated from below and rotating about vertical axis, under local thermal non-equilibrium hypothesis is studied. Linear and nonlinear stability analysis of the conduction solution is performed. Coincidence between the linear instability and the global nonlinear stability thresholds with respect to the L2—norm is proved. Article Highlights A necessary and sufficient condition for the onset of convection in a rotating anisotropic porous layer has been obtained. It has been proved that convection can occur only through a steady motion. A detailed proof is reported thoroughly. Numerical analysis shows that permeability promotes convection, while thermal conductivities and rotation stabilize conduction.

Non-linear Stability in Transitional and Rotatory Regime of the Cooking of Gari, Food Based on Cassava Tubers

The present study focuses on the non-linear stability in the transient rotary regime of the cooking process of gari. The process of cooking gari consists of a rotating rectangular cavity filled with grated cassava flour, pressed, retted and considered to be an anisotropic porous medium in a permeably saturated viscoelastic fluid. The cavity is heated from below to a constant temperature. The lower wall of the cavity is impermeable and the upper wall is permeable. Using a numerical method, we have established the transient expressions of the Nusselt number, the flow and temperature fields as a function of the anisotropy parameters of the porous medium and of the Taylor number. The results obtained showed that the anisotropy of the porous medium and the Taylor number greatly influenced the cooking of gari over time.

The Onset of Soret Driven Ferrothermoconvective Instability in the Presence of Darcy Porous Medium with Anisotropy Effect and MFD Viscosity

The effect of magnetic field dependent (MFD) viscosity on Soret driven ferrothermohaline convection in a densely packed anisotropic porous medium has been studied. The Soret effect is focused on the system. A linear stability analysis is carried out using a normal mode technique and a perturbation method is applied. It is found that a stationary mode is favorable for the Darcy model. Vertical anisotropy tends to destabilize the system and the magnetization effect is found to stabilize the system. It is also found that the MFD viscosity delays the onset of convection. Numerical computations are made and illustrated graphically.