THE EFFECT OF THE RATIO ON MAGNETO-HYDRODYNAMIC VISCOELASTIC FLUID LAYER HEATED FROM BELOW

The effect of the ratio (the strain retardation time to the sress relaxation time) on magneto-hydrodynamic viscoelastic fluid (Walters ’ lquid B’) layer heated From below confined between tow horizontal planes has been studied. Linear stability theory and normal mode analysis are used to derive an differential equation of sixth order, and an exact solution for natural instability is obtained.Critical Rayleigh numbers and wave numbers for the onset of instability are discussed graphically as functions of , the Chandrasekhar number for various values of the Fourier number, and relaxation time at a constant value for Prandtl number