Interaction Between the Torsional Vibration of a Circular Rod and an Adjacent Viscous Fluid

This paper deals with the effect of an adjacent viscous fluid on the torsional vibration of a circular rod excited by a transducer at one end. The interaction between the torsional vibration of the rod and the fluid has been studied theoretically and expressed in terms of mechanical impedance. The theoretically-obtained result that the mechanical impedance is proportional to the square root of the viscosity times mass density of the fluid has been confirmed by the experiment measuring electric impedance. This paper demonstrates that a torsionally-vibrating rod can be used as a sensor for measuring the viscosity of a fluid.