Extensional flow : a mathematical perspective

摘要: Extensional flow has been studied extensively for less than half the lifetime of word “rheology”, although measurement viscosity from extensional experiments can be traced back to beginning this century. In recent years has, however, attracted a great deal attention in conferences, workshops and special issues journals. This coincided with interest, both scientific industrial, elasticoviscous fluids, notably polymer solutions molten polymers. The particular success specialized, carefully targetted or focussed, is highlighted. A personal reflection offered here on some point view an applied mathematician. state art, as far concerned, briefly surveyed. Both theoretical practical aspects task obtaining useful properties are outlined, drawing heavily review by James Walters. Particular paid spinning experiments, investigations author. merits defining “spinning viscosity”, addition formally defined tensile viscosity, advanced. idea general approximations flows reviewed highlighted, particularly connection Metzner's primary field (EPF) approximations. Finally qualitative behaviour model fluids (in flows) illustrated new result boundedness unsteady uniaxial extension FENS-P dumbbell presented.