SHEAR BANDING FLOW IN THE JOHNSON-SEGALMAN FLUID

The behaviour of the Johnson-Segalman fluid in a Couette geometry is i nvestigated with a combination of numerical, analytical and simulation techniques. The results strongly suggest that there exists a selectio n mechanism for the position of the interface of discontinuity due to the constitutive instability typical of models with non-monotonic cons titutive equations. This implies that the spurt phenomenon exhibits a jump discontinuity instead of a change of slope in the flow curve.