title: Rate of shear of an ultrasonic oscillating rod viscosity probe.
abstract: Ultrasonic oscillating rod probes have recently been used by researchers to measure viscosity and/or density in fluids. However, in order to use such probes to characterise the rheological properties of fluids, it is necessary to define the shear rate produced by the probe. This paper proposes an analytical solution to estimate the shear rate of ultrasonic oscillating rod viscosity probes and a method to measure their maximum operational shear rate. A relationship is developed which relates the torsional surface velocity of an oscillating cylindrical rigid body to the rate of shear in its vicinity. The surface displacement and torsional surface velocity of a torsional probe of length 1000 mm and diameter 1mm were measured over the frequency range from 525 to 700 kHz using a laser interferometer and the maximum shear rate estimated. The reported work provides the basis for characterising shear rate for such probes, enabling their application for rheological investigations.
authors.affiliation: Department of Mechanical, Materials and Manufacturing Engineering, Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, UK. Electronic address: Amir.Rabani@nottingham.ac.uk.
authors.forename: A
authors.initials: A
authors.lastname: Rabani
authors.affiliation: Department of Chemical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK.
authors.forename: V J
authors.initials: VJ
authors.lastname: Pinfield
authors.affiliation: Department of Electrical and Electronic Engineering, Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
authors.forename: R E
authors.initials: RE
authors.lastname: Challis
keywords: Laser interferometer; Shear rate; Torsional viscometer; Ultrasonic oscillating rod; Viscosity