Numerical study of the wire form function versus the liquid density of the surrounding medium

Abstract

This communication presents the developments of an original method of the density measurement of a liquid. The measurement method is theoretically based on the Resonant Scattering Theory (RST). The RST gives a non-linear relation between the ultrasonic pressure backscattered by an object (here, wire) represented by its form function and the liquid density into which the object is immersed. The developed method, already presented [10], needs two kinds of wire: a “measurement wire” and a “calibration wire”. This article presents the study of the sensitivity of the method. The sensitivity is represented by the partial derivative of the wire form function according to the liquid density. This derivative is analyzed in function of the wire parameters (size, density and acoustical velocities) and the frequency. Globally, the sensitivity increases when the density of the wire and the acoustical velocities decrease. From this study, we can choose the material of the wires. The “measurement wire” must be made of a material having low density and velocities. The “calibration wire” must be made of a material having high density and velocities. The choices of the size of the wire and the frequency are joint by the reduced wave number ka. The experimental problems at the acoustical resonances limits the choice to ka domain approximately ranging from 0.5 to 1.0. Liquid density measurement, form function, scattering, wire, milk density