- Shear rate
**Shear rate**is the rate at which ashear is applied.**imple Shear**Shear rate is defined using the following equation:

$dot\; gamma\; =\; frac\; \{\; u\}\; \{h\}$

Where:

*$gamma$ = The shear rate, measured in reciprocal seconds

*$u$ = The velocity, measured in metres per second

*$h$ = The distance between the two parallel faces that are experiencing the shear.Or,$dot\; gamma\_\{ij\}=frac\; \{partial\; v\_i\}\; \{partial\; x\_j\}\; +\; frac\{partial\; v\_j\}\; \{partial\; x\_i\}$

For the

simple shear case, it is just agradient ofvelocity in a flowing material. TheSI unit of measurement for shear rate is sec^{-1}, expressed as "reciprocal seconds" or "inverse seconds."Cite web

title = Brookfield Engineering - Glossary section on Viscosity Terms

accessdate = 2007-06-10

url = http://www.brookfieldengineering.com/education/viscosity_glossary.asp]For a

Newtonian fluid wallShear stress ($au\_\{w\}$) can be related to shear rate by$au\_\{w\}\; =\; \{dot\; gamma\_\{x\}\; mu\}$, where $mu$ is theViscosity of the fluid. For Non-Newtonian fluids, there are differentconstitutive laws depending on the fluid, which relates thestress tensor to the shear rate tensor.**References**

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