Viscosity Units
Viscosity is a measure of a fluid’s resistance to flow. It describes how thick or thin a fluid is, indicating how easily it pours at a specific temperature. The viscosity of a substance is a crucial parameter in many applications, affecting the performance and efficiency of systems involving fluid flow, such as in lubrication, chemical processing, and fluid transport.
Units of Viscosity
There are two main types of viscosity measurements:
Dynamic (Absolute) Viscosity: This measures the fluid’s internal resistance to flow. The SI unit for dynamic viscosity is the Pascal-second (Pa·s), but the centipoise (cP) is also commonly used, especially in the CGS (centimeter-gram-second) system.
Kinematic Viscosity: This measures the dynamic viscosity divided by the fluid’s density, essentially describing how a fluid’s flow is influenced by gravity. The SI unit for kinematic viscosity is the square meter per second (m²/s), but the centistoke (cSt) is more commonly used.
Below is a table presenting different viscosity units and their conversion factors
Viscosity Type | Unit | Conversion Factor | Equivalent in SI Units (Pa·s or m²/s) |
---|---|---|---|
Dynamic Viscosity | Pascal-second (Pa·s) | 1 Pa·s = 1 | 1 Pa·s |
Poise (P) | 1 P = 0.1 Pa·s | 0.1 Pa·s | |
Centipoise (cP) | 1 cP = 0.001 Pa·s | 0.001 Pa·s | |
Kinematic Viscosity | Square meter per second (m²/s) | 1 m²/s = 1 | 1 m²/s |
Stoke (St) | 1 St = 0.0001 m²/s | 0.0001 m²/s | |
Centistoke (cSt) | 1 cSt = 0.000001 m²/s | 0.000001 m²/s |