VISCOSITY MEASUREMENT OF AN ENCLOSED LIQUID USING ULTRASOUND

A novel method for noninvasive measurement of viscosity is proposed. The method is based on acoustic streaming, which can be induced by ultrasound in a liquid enclosed in a container. Measurements of the streaming velocity, obtained with wetted transducers at 10.4 MHz, show that it is inversely proportional to the viscosity of the liquid. Since the ultrasound Doppler technique can be used to measure flow velocities of enclosed liquids containing scatters, the described method would appear to be well suited for the assessment of the viscosity or changes in the viscosity of such liquids enclosed in sealed containers. This opens up new possibilities in quality control of sterile packaged products such as milk and blood. Accuracy of the method in the reported experiments is found to be within +/- 6%.