Theoretical and Experimental Studies of the Mechanics of Viscoelastic Liquids

摘要

Theoretical and experimental studies of a wide range of problems in the rheometry of viscoelastic fluids are described. A device to measure the shear relaxation function has been invented (the wave speed meter). Investigations of the conditions under which the equations for the flow of viscoelastic liquids can change type have been carried out. The results from experiments and analyses on a variety of problems associated with bicomposed flows of liquids with different viscosities are presented. These included liquid rollers, the flow of two liquids in a pipe, and Taylor instability with two immiscible liquids. Analysis and experiments of the motion of a viscoelastic liquid between eccentric rotating cylinders are described. Some analytical results for the extrudate swell problem are presented. The climbing constants for a wide range of viscoelastic liquids have been measured. Other projects include stability analyses for several flow geometries; experiments on viscoelastic liquid breakup; and experiments on the stability of a rotating and coning cylinder. Keywords include: Rheology; Viscoelastic liquids; Wave speed meter; Discontinuities; Hyperbolicity; Change of type; Bicomponent flows; Rotating cylinders; Liquid rollers; Jets; Die swell; Liquid breakup; Climbing constants; Fading memory; Instabilities; Coning cylinder.