Measurement of the Viscosity and Shear Elasticity of Liquids by Means of a Torsionally Vibrating Crystal

Abstract

Abstract This paper describes a method of measuring viscosities of liquids at high-frequencies by means of oscillating cylinders, in which a torsionally vibrating crystal generates a viscous wave in the medium to be measured. Both a reactance and a resistance loading occur in the crystal which lowers its frequency and raises the measured resistance at resonance. The viscosity may then be determined by measuring the changes in the properties of the crystal. By varying the voltage on the crystal, the shearing displacement can be varied and hence the viscosity can be measured as a function of shearing stress. Measurements on light oils over a viscosity range from 0.01 poise to 10 poises check within a few per cent when made with rough temperature-control conditions.