Rheometry Utilizing Ultrasonic Velocity Profiler

―Importance of Flow Measurement and Propositions―

Abstract

We introduced our recent works on development of rheometry utilizing ultrasonic velocity profiling (UVP) that can capture spatio-temporal velocity information even in opaque fluids. Rheological properties describing relations in stress, strain and strain rate are reflected into flow field, and analyzing flow information obtained in simple unsteady flow configurations may provide the rheological properties. We adopted cylindrical vessel with regular oscillation on the cylinder wall as the configuration, and evaluated effective Newtonian viscosity of viscous oil with dispersed small bubbles and time-dependent behavior of montmorillonite suspension that is one of thixotropic fluids to demonstrate applicability of the rheometry. We also explained novel idea of ‘flow surface’ that aims to describe rheological properties without using rheology models.