Numerical estimates for the bulk viscosity of ideal gases
Abstract
We estimate the bulk viscosity of a selection of well known ideal gases. A relatively simple formula is combined with published values of rotational and vibrational relaxation times. It is shown that the bulk viscosity can take on a wide variety of numerical values and variations with temperature. Several fluids, including common diatomic gases, are seen to have bulk viscosities which are hundreds or thousands of times larger than their shear viscosities. We have also provided new estimates for the bulk viscosity of water vapor in the range 3801000 K. We conjecture that the variation of bulk viscosity with temperature will have a local maximum for most fluids. The LambertSalter correlation is used to argue that the vibrational contribution to the bulk viscosities of a sequence of fluids having a similar number of hydrogen atoms at a fixed temperature will increase with the characteristic temperature of the lowest vibrational mode.
 Publication:

Physics of Fluids
 Pub Date:
 June 2012
 DOI:
 10.1063/1.4729611
 Bibcode:
 2012PhFl...24f6102C
 Keywords:

 aerodynamics;
 computational fluid dynamics;
 equations of state;
 rotationalvibrational states;
 viscosity;
 47.40.x;
 51.10.+y;
 51.20.+d;
 51.30.+i;
 47.11.j;
 Compressible flows;
 shock waves;
 Kinetic and transport theory of gases;
 Viscosity diffusion and thermal conductivity;
 Thermodynamic properties equations of state;
 Computational methods in fluid dynamics