Resonant torsional vibrations: an application to dynamic viscometry

Abstract

A family of sensors which measure the complex coefficient of dynamic viscosity (η*) is discussed. Using a first order approximation to a general viscoelastic fluid, it is shown how these instruments determineη* for a general linear viscoelastic fluid. The measurement technique employed relates the linear viscous damping and resonant frequency of these instruments in the presence and absence of fluid toη*. This analysis also provides the inherent limitations of the sensors.