Mechanical Impedance at the Interface between a Torsionally-Vibrating Rod and a Viscous Fluid

비틀림 진동 봉과 점성 유체의 경계면에서의 역학적 임피던스

This paper deals with the measurement of the fluid viscosity by using the torsional vibration of a circular red excited by a torsional vibrator at one end. The effect of an adjacent viscous fluid on the torsional vibration of the rod has been studied theoretically and expressed in terms of the mechanical impedance. The theoretically-obtained trend that the mechanical impedance is proportional to the square root of the viscosity times the density of the fluid has been confirmed by the impedance measurement. The paper demonstrates that a torsionally-vibrating rod can be used as a sensor to measure the viscosity of a fluid.