An idealized treatment of a fluid between two large parallel plates (to permit ignoring
edge effects) of area ,
separated by a distance .
If one plate moves relative to the other with a constant velocity ,
requiring a force
acting in the direction of movement, and the density, pressure, and viscosity
throughout the fluid are constant, the Newtonian equation can be coupled with the
equations of motion and of continuity to show that the velocity gradient
in the fluid is constant
), and that
This idealized case (simple shear) is sometimes used to define shear viscosity
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
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. https://doi.org/10.1351/goldbook