RAYLEIGH-TAYLOR INSTABILITY OF VISCOUS-VISCOELASTIC FLUIDS THROUGH POROUS-MEDIUM

Rayleigh-Taylor instability of a Newtonian viscous fluid overlying an Oldroydian viscoelastic fluid through porous medium is considered. As in both Newtonian viscous-viscous fluids, the system is stable for pot entially stable case and unstable for potentially unstable case in the present problem also. The effects of a uniform horizontal magnetic fi eld and a uniform rotation on the problem are also considered separate ly. The presence of magnetic field stabilizes certain wave-number band whereas system was unstable for all wave-numbers m the absence of mag netic field for the potentially unstable configuration. However, the s ystem becomes unstable for a viscous fluid overlying an Oldroydian vis coelastic fluid through porous medium, in the presence of a uniform ro tation.