From Wikipedia, the free encyclopedia.
A non-Newtonian fluid is a fluid in which shear stress is not simply proportional solely to the velocity gradient, perpendicular to the plane of shear. Non-Newtonian fluids may not have a well-defined viscosity.
Principle types of non-Newtonian fluid include:
{|align=left border=1 |Type of fluid |Characteristics |Examples |- |Plastic | |Ductile metals |- |Pseudo-plastic |Apparent viscosity reducing with rate of shear |Some colloids, clay, milk, gelatine, blood and liquid cement |- |Perfectly plastic |Strain does not result in opposing stress | |- |Bingham plastic | | |- |Dilatent |Apparent viscosity increasing with rate of shear |Concentrated solution of sugar in water, suspensions of rice starch |- |Rheopectic |Apparent viscosity increases with duration of stress |Some lubricants |- |Thixotropic |Apparent viscosity decreases with duration of stress |Non-drip paints and tomato ketchup |- |Visoelastic |Having both viscous and elastic properties |Bitumen, dough and nylon |}
See also: Newtonian fluid | rheology | viscosity
