Viscous heating and the stability of Newtonian and viscoelastic Taylor-Couette flows

The effects of viscous heating on the stability of Taylor-Couette flow were investigated through flow visualization experiments for Newtonian and visc oelastic fluids. For highly viscous Newtonian fluids, viscous heating drive s a transition to a new, oscillatory mode of instability at a critical Reyn olds number significantly below that at which the inertial transition is ob served in isothermal flows. The effects of viscous heating may explain the discrepancies between the observed and predicted critical conditions and th e symmetry of the disturbance flow for viscoelastic instabilities.