Phase space analysis of the spurt phenomenon for the Giesekus viscoelastic fluid model

Abstract The spurt phenomenon is a flow instability which occurs in pressure-driven parallel shear flows of viscoelastic liquids. This phenomenon is characterized by an abrupt increase in the volumetric throughput at a critical value of the driving pressure gradient. Recently, non-monotone (steady shear response) constitutive equations have been proposed to model this phenomenon. We analyze the startup problem for the Giesekus model, both asymptotically and numerically, and compare the results to those obtained for other models.