THE IMPACT OF IDEAL ELASTIC LIQUIDS IN THE DEVELOPMENT OF NON-NEWTONIAN FLUID-MECHANICS

Research in non-Newtonian fluid mechanics has been characterized by the theoretical types (the left wing) who make predictions that cannot be observed and by the experimental types (the right wing), on the other hand, who make observations that no one can predict. In this paper, the authors demonstrate how the left wing and the right wing have been forced to interact as a result of the discovery and subsequent development of constant-viscosity elastic liquids, the so-called Boger fluids. They review the use of constant-viscosity elastic liquids in experimental programs to observe elastic effects in flows in the absence of fluid inertia and a shear rate dependent viscosity and show how these observations have motivated the numerical solutions of real problems. Particular attention is directed to tubular exit (spinning) flows and the interaction that has occurred between observation and prediction.