Ultrasonic Attenuation and Speed of Sound of Cornstarch Suspensions

TL;DR

This study uses ultrasonic techniques to measure the speed of sound and attenuation in cornstarch suspensions, revealing how these properties vary with concentration and providing insights into their material characteristics.

Contribution

It provides the first ultrasonic characterization of cornstarch suspensions, quantifying sound speed and attenuation across different concentrations in a density-matched solution.

Findings

Speed of sound increases with cornstarch concentration.

Attenuation coefficient rises significantly with concentration.

Bulk modulus of cornstarch granules estimated at 1.2 x 10^{10} Pa.

Abstract

The goal of this study is to contribute to the physics underlying the material properties of suspensions that exhibit shear thickening through the ultrasonic characterization of suspensions of cornstarch in a density-matched solution. Ultrasonic measurements at frequencies in the range of 4 to 8 MHz of the speed of sound and the frequency-dependent attenuation properties are reported for concentrations of cornstarch in a density-matched aqueous (cesium chloride brine) suspension, ranging up to 40% cornstarch. The speed of sound is found to range from 1483 +/- 10 m/s in pure brine to 1765 +/- 9 m/s in the 40% cornstarch suspension. The bulk modulus of a granule of cornstarch is inferred to be (1.2 +/- 0.1) X 10^{10} Pa. The attenuation coefficient at 5 MHz increases from essentially zero in brine to 12.0 +/- 1.2 dB/cm at 40% cornstarch.