Temperature dependence of bulk viscosity in water using acoustic spectroscopy

Abstract

Despite its fundamental role in the dynamics of compressible fluids, bulk\nviscosity has received little experimental attention and there remains a\npaucity of measured data. Acoustic spectroscopy provides a robust and accurate\napproach to measuring this parameter. Working from the Navier-Stokes model of a\ncompressible fluid one can show that the bulk viscosity makes a significant and\nmeasurable contribution to the frequency-squared acoustic attenuation. Here we\nemploy this methodology to determine the bulk viscosity of Millipore water over\na temperature range of 7 to 50 degrees Celsius. The measured attenuation\nspectra are consistent with the theoretical predictions, while the bulk\nviscosity of water is found to be approximately three times larger than its\nshear counterpart, reinforcing its significance in acoustic propagation.\nMoreover, our results demonstrate that this technique can be readily and\ngenerally applied to fluids to accurately determine their temperature dependent\nbulk viscosities.\n