Non-Newtonian fluids, time independent
The viscosity of a Non-Newtonian time independent fluid is dependent not only on temperature but also on shear rate.
Depending on how viscosity changes with shear rate the
flow behaviour is characterised as:
- shear thinning - the viscosity decreases with increased shear rate
- shear thickening - the viscosity increases with increased shear rate
- plastic - exhibits a so-called yield value, i.e. a certain shear stress must be applied before flow occurs
Shear thinning fluids are also called pseudoplastic and shear thickening fluids are also called dilatant.
Examples of shear thinning fluids:
- paint
- shampoo
- slurries
- fruit juice concentrates
- ketchup
Examples of shear thickening fluids:
- wet sand
- concentrated starch suspensions
Examples of plastic fluids:
- quark
- tomato paste
- tooth paste
- hand cream
- some ketchups
- grease
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