Ultrasonic Parameters as a Function of Absolute Hydrostatic Pressure. II. Mathematical Models of the Speed of Sound in Organic Liquids

Abstract

Polynomial expressions for the speed of sound as a function of pressure for 68 different organic liquids are presented in tabular form. The liquids form a subset of those discussed in the companion paper: Ultrasonic parameters as a function of absolute hydrostatic pressure. I. A review of the data for organic liquids. The polynomial expressions are based upon the experimental results reported by many different researchers. For some common liquids, such as benzene, hexane, ethanol, and carbon tetrachloride, the results of as many as five different researchers are reported. These results sometimes vary widely—far more than would be expected from calculated experimental uncertainties. An analysis is presented of how well pressure-dependent polynomials fit the experimental data when the number of coefficients is increased. The error in the polynomial fit is also explored when both pressure and temperature dependencies are present. Finally, differences between ultrasonic and Brillouin scattering experimental results are discussed.