Extension of the torsional crystal viscometer to measurements in the time domain

This paper reports the first wide-ranging application of the free-mode measurement technique to a torsional crystal viscometer. The viscous damping of the fluid on the surface of the crystal is detected in the time domain by observing the freely decaying torsional oscillation of the crystal. Previously, the torsional crystal viscometer was used exclusively in a forced mode of measurement, where the response of the crystal is determined in the frequency domain by scanning through the resonance.