THE ONSET OF DOUBLE-DIFFUSIVE CONVECTION IN A MAXWELL FLUID SATURATED POROUS LAYER

The onset of double-diffusive convection in a Maxwell fluid-saturated porous layer is studied using linear and weak nonlinear stability analyses. The onset criterion for oscillatory convection is derived analytically. The effect of the stress relaxation parameter, Lewis number, solute Rayleigh number, Darcy-Prandtl number, and normalized porosity parameter on the stationary, oscillatory, and finite-amplitude convection is shown graphically. The nonlinear theory is based on the truncated representation of the Fourier series method and is used to find the heat and mass transfer. The transient behavior of the Nusselt and Sherwood numbers is investigated by solving the finite-amplitude equations using the Runge-Kutta method. The effect of the viscoelastic parameter on heat and mass transfer is brought out.