The Torsional Quartz-Crystal Viscometer

A complete theoretical analysis of the fluid and solid dynamics of the torsional quartz crystal viscometer is presented which for the first time, establishes a firm theoretical basis for two working equations whereby the viscosity of a fluid may be determined from measurements of the resonant frequency of the crystal and the width of the resonance when immersed in the fluid. Modern instrumentation means that it is possible to achieve higher resolution in the measurement of these two quantities than hitherto and the new theory opens the way to securing a concomitant accuracy in the determination of viscosity.