ON THE STABILITY OF 2 SUPERPOSED WALTERS-B' VISCOELASTIC LIQUIDS

The stability of the plane interface separating two viscoelastic (Welt ers B') superposed fluids of uniform densities has been studied. The s tability analysis has been carried out, for mathematical simplicity, f or two highly viscoelastic fluids of equal kinematic viscosities and e qual kinematic viscoelasticities. For the stable configuration, the sy stem is found to be stable or unstable for the wave-number range k < o r > (2v')(-1/2), depending on kinematic viscoelasticity v'. However, t he system is found to be unstable for the unstable configuration. The behaviour of growth rates with respect to kinematic viscosity and kine matic viscoelasticity are examined analytically.