Newtonian fluid

physics

Also known as: Newtonian liquid, linearly viscous fluid, viscous fluid, viscous liquid(Show More)

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June 17, 2026

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A Newtonian fluid is a fluid whose viscosity remains constant regardless of the rate of flow. Viscosity is the resistance a fluid offers to a change in shape or movement between its layers. Think of it as internal friction within the fluid.12

Sir Isaac Newton first described this behavior, where the shear stress is directly proportional to the rate of shear strain. Fluids that don't follow this principle, where viscosity changes with shear rate or over time, are called non-Newtonian fluids. Examples of Newtonian fluids include water and air, while substances like molasses or paint can be non-Newtonian.23

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amorphous solid
Distinction between crystalline and amorphous solids
…erroneously describe glasses as undercooled viscous liquids, but this is actually incorrect. Along the section of route 2 labeled liquid in Figure 3, it is the portion lying between T_f and T_g that is correctly associated with the description of the material as an undercooled liquid (undercooled meaning that its…
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…erroneously describe glasses as undercooled viscous liquids, but this is actually incorrect. Along the section of route 2 labeled liquid in Figure 3, it is the portion lying between T_f and T_g that is correctly associated with the description of the material as an undercooled liquid (undercooled meaning that its…
Read More

fluid
…and are further distinguished as Newtonian fluids if the viscosity is constant for different rates of shear and does not change with time. The viscosity of non-Newtonian fluids either varies with the rate of shear or varies with time, even though the rate of shear is constant. Fluids in a…
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…and are further distinguished as Newtonian fluids if the viscosity is constant for different rates of shear and does not change with time. The viscosity of non-Newtonian fluids either varies with the rate of shear or varies with time, even though the rate of shear is constant. Fluids in a…
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deformation and flow
Viscous liquids consist of molecules that, like those of the perfect fluid, are in contact with one another but do exert forces on one another so that shearing motions within the liquid are resisted. These internal shearing forces produce the characteristic behaviour of liquids such…
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Viscous liquids consist of molecules that, like those of the perfect fluid, are in contact with one another but do exert forces on one another so that shearing motions within the liquid are resisted. These internal shearing forces produce the characteristic behaviour of liquids such…
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fluid mechanics
Stresses in laminar motion
…for what is called a Newtonian fluid is
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…for what is called a Newtonian fluid is
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viscosity
…in this way are called Newtonian fluids in honour of Sir Isaac Newton, who first formulated this mathematical description of viscosity.
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…in this way are called Newtonian fluids in honour of Sir Isaac Newton, who first formulated this mathematical description of viscosity.
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