Torsional Wave Sensor—A Theory

Abstract

Experimental observations suggest that the speed of propagation of torsional waves in a solid, elastic wave guide with a noncircular cross section is inversely proportional to the density of the fluid adjacent to the waveguide. Thus, by measuring the speed of propagation of the torsional wave, one can infer the density of the fluid. Additionally, the above procedure may be utilized to measure, among other things, liquid level and the composition of binary solutions. A simple theory is derived to correlate the torsional wave speed and the fluid density; the theoretical results are also compared with experiments.