viscosity
Sign in to saveWhen two fluid layers move relative to each other, a friction force develops between them and the slower layer acts to slow down the faster layer. This internal resistance to flow is described by the fluid property called viscosity, which reflects the internal stickiness of the fluid. In liquids, viscosity arises from cohesive molecular forces, while in gases it results from molecular collisions. Except for the case of superfluidity, there is no fluid with zero viscosity, and thus all fluid flows involve viscous effects to some degree.
AI overview
Viscosity is a fluid's internal resistance to flow—essentially how "sticky" or thick a fluid is, caused by friction between moving layers of the fluid. This property matters because it affects how all fluids behave when they move, from how easily oil pours to how air flows around objects.
AI-generated from the Wikipedia summary — may contain errors.
Key facts
- Physical quantity.bgcolour
- {red}
- Physical quantity.name
- Viscosity
- Physical quantity.image
- Viscosities|300px
- Physical quantity.caption
- A simulation of liquids with different viscosities. The liquid on the left has lower viscosity than the liquid on the right.
- Physical quantity.unit of dynamic viscosity
- Pa·s = (N·s)/m2 = kg/(s·m)
- Physical quantity.symbols
- ,
- Physical quantity.dimension
- \mathsf{M} \mathsf{L}^{-1} \mathsf{T}^{-1}
via Wikipedia infobox
Article
38 sectionsContents
- Etymology
- Definitions
- Dynamic viscosity{{anchor|Dynamic viscosity}}<!-- 'Dynamic viscosity' redirects here. -->
- {\rm Pa{\cdot}s}
- Kinematic viscosity
- \mathrm {\frac {J}{kg} {\cdot}s}
- General definition
- Momentum transport
- Newtonian and non-Newtonian fluids
- In solids
- Measurement
- Units
- Molecular origins
- Pure gases
- Elementary calculation of viscosity for a dilute gas
- Chapman–Enskog theory
- Bulk viscosity
- Pure liquids
- Mixtures and blends
- Gaseous mixtures
- Blends of liquids
- Solutions and suspensions
- Aqueous solutions
- Suspensions
- Amorphous materials
- Eddy viscosity
- Prediction
- Selected substances
- Water
- Air
- Other common substances
- Order of magnitude estimates
- See also
- References
- Footnotes
- Citations
- Sources
- External links
{{Infobox Physical quantity | bgcolour = {red} | name = Viscosity | image = Viscosities|300px | caption = A simulation of liquids with different viscosities. The liquid on the left has lower viscosity than the liquid on the right. | unit of dynamic viscosity = Pa·s = (N·s)/m2 = kg/(s·m) | symbols = , | derivations = | dimension = \mathsf{M} \mathsf{L}^{-1} \mathsf{T}^{-1} }}
When two fluid layers move relative to each other, a friction force develops between them and the slower layer acts to slow down the faster layer. This internal resistance to flow is described by the fluid property called viscosity, which reflects the internal stickiness of the fluid. In liquids, viscosity arises from cohesive molecular forces, while in gases it results from molecular collisions. Except for the case of superfluidity, there is no fluid with zero viscosity, and thus all fluid flows involve viscous effects to some degree.