Linear and nonlinear response of viscoelastic fluids
Abstract
The methods of continuum mechanics are used to obtain approximate constitutive relations for simple flows of viscoelastic fluids. Measurements were made using polymeric materials to verify some solutions of the derived equations. An infinitesimal disturbance superimposed on a basic state flow consisting of either a steady shearing or extension is shown to cause stresses that are linear functionals of this disturbance. In this theory, three functions characterize the disturbance stresses for steady extensions. The dynamics of small oscillatory displacements about an extensional flow are examined. Both a linear and a nonlinear theory of nonNewtonian materials are used to solve problems in which disturbances are in the same direction as the steady shearing motion. These solutions relate measurable quantities to material properties and were the basis for two experiments.
 Publication:

Ph.D. Thesis
 Pub Date:
 1978
 Bibcode:
 1978PhDT........44P
 Keywords:

 Continuum Mechanics;
 Nonnewtonian Fluids;
 Stresses;
 Viscoelasticity;
 Flow Equations;
 Fluid Flow;
 Linear Systems;
 Nonlinear Systems;
 Nonnewtonian Flow;
 Rheology;
 Fluid Mechanics and Heat Transfer