IUPAC > Gold Book > alphabetical index > V > volume viscosity (or dilatational viscosity)


volume viscosity (or dilatational viscosity)

A quantity ζ which enters into equations at any point where the flow involves a change in volume, i.e. is dilatational. If the deformation is purely dilatational, the average of three normal stress components is:
σ = 1 3 ( σ x x + σ y y + σ z z ) = − p + ζ ( ∂ v x ∂ x + ∂ v y ∂ y + ∂ v z ∂ z )
where p is the hydrostatic pressure at the point considered in the absence of motion.
PAC, 1979, 51, 1213 (Manual of symbols and terminology for physicochemical quantities and units. Appendix II: Definitions, terminology and symbols in colloid and surface chemistry. Part 1.13. Selected definitions, terminology and symbols for rheological properties) on page 1216
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IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. doi:10.1351/goldbook.
Last update: 2014-02-24; version: 2.3.3.
DOI of this term: doi:10.1351/goldbook.V06650.
Original PDF version: http://www.iupac.org/goldbook/V06650.pdf. The PDF version is out of date and is provided for reference purposes only. For some entries, the PDF version may be unavailable.
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