shear viscosity

https://doi.org/10.1351/goldbook.S05642
For a
Newtonian fluid
, the shear
viscosity
is often termed simply
viscosity
since in most situations it is the only one considered. It relates the shear components of stress and those of rate of
strain
at a point in the fluid by: σxy=σyx=η (νxy+νyx)=2 η γ.yx where γ.yx, the shear component of rate of
strain
is defined as follows: γ.yx=12 (νxy+νyx) Corresponding relations hold for σxz and σyz; σxy is the component of stress acting in the y-direction on a plate normal to the x-axis; νx, νy, νz are the components of velocity.
See also:
shear dependent viscosity
Source:
PAC, 1979, 51, 1213. (Terminology and Symbols in Colloid and Surface Chemistry Part 1.13. Definitions, Terminology and Symbols for Rheological Properties) on page 1216 [Terms] [Paper]