Compressional Viscosity and Sound Absorption in Water at Different Temperatures

Abstract

The temperature dependence of the coefficient of absorption ($2\ensuremath{\alpha}{\ensuremath{\nu}}^{\ensuremath{-}2}$) of ultrasonic waves in water was measured from 0\ifmmode^\circ\else\textdegree\fi{}C to 33\ifmmode^\circ\else\textdegree\fi{}C. Values range from 137\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}17}$ at 0\ifmmode^\circ\else\textdegree\fi{}C to 40\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}17}$ at 33\ifmmode^\circ\else\textdegree\fi{}C. In particular at 4\ifmmode^\circ\else\textdegree\fi{}C where the sound propagation is isothermal the value 101\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}17}$ is found, and is to be compared with a shear viscosity contribution of 30\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}17}$. Therefore the excess cannot be caused by the slowness of energy exchange between the internal and external degrees of freedom. The excess absorption is used to calculate the value of a new coefficient of compressional viscosity $k$, which is found to be 0.052 poise at 4\ifmmode^\circ\else\textdegree\fi{}C and 0.026 poise at 20\ifmmode^\circ\else\textdegree\fi{}C. A general discussion of the origin of sound absorption in liquids is included, with particular applications to recent measurements.