Mathematical modeling of the effects of attenuation and system electronic coupling on the determination of speed of sound in ultrasonic interferometry

• Main Authors: Yau, Ching Koon, Jesudason, Christopher Gunaseelan
• Format: Article
• Published: Springer 2018
• Subjects: Q Science (General); QD Chemistry
• Online Access: http://eprints.um.edu.my/20294/; https://doi.org/10.1007/s10910-018-0897-2
• Institution: Universiti Malaya

Ultrasonic interferometry is an indispensable tool in molecular chemistry and imaging, inclusive of liquid state studies where the standard theory is used to determine many physico-chemical parameters, such as the isentropic compressibility and adiabatic bulk modulus. The first principle analysis conducted here augments the standard model with potentially significant consequences in the interpretation of these parameters and the output spectrum. The effect of attenuation of a wave on the observed separation between peaks in acoustic interferometry is a focus of the investigation. Important aspects of the theory of Hubbard and others were collated to derive two mathematical models that were used to fit experimental spectra. The first model does not assume fictitious quantities found in Hubbard’s theory and fits the experimental data well. The second model includes the effects of the electronics of the measuring system and is in excellent agreement with the experimental data. Theoretical and numerical analyses were performed to validate the two models. Numerically, the attenuation of a wave is shown to cause the peaks to deviate either positively or negatively from the otherwise ideal half-wavelength of λ/ 2 and exact equations governing such deviations are derived that could have significant implications in theory and applications.