Viscosity (Kinematic)
How to Convert m²/s to Centistokes (cSt)
To convert a measurement from square meters per second to centiStokes, you use the conversion factor that 1 m²/s is equal to 1,000,000 cSt.
Example:
Convert a kinematic viscosity of 0.0005 m²/s to cSt.
0.0005 m²/s × 1,000,000 cSt/(m²/s) = 500 cSt
Answer: A kinematic viscosity of 0.0005 m²/s is equal to 500 centiStokes.
Flow Under Gravity: Understanding Kinematic Viscosity
Kinematic viscosity is a measure of a fluid's inherent resistance to flow when no external force is exerted, except for gravity. It is the ratio of a fluid's dynamic viscosity (its internal 'thickness') to its density. While dynamic viscosity describes how a fluid responds to an applied force, kinematic viscosity describes how it behaves under the force of gravity alone. It answers the question: "How fast will this fluid spread out if I just pour it onto a flat surface?" A fluid with high kinematic viscosity will flow slowly and spread out less, while one with low kinematic viscosity will flow quickly and spread out widely.
This property is particularly important in fluid dynamics, especially in calculations involving the Reynolds number, which is used to predict flow patterns (laminar vs. turbulent flow). It is widely used in industries where fluid flow behavior is critical, such as the petroleum industry for characterizing fuels and lubricants, and in hydraulics. The SI unit for kinematic viscosity is square meters per second (m²/s). However, a much more common unit from the CGS system is the Stokes (St), named after the Irish physicist George Gabriel Stokes, and even more commonly, its sub-unit, the centiStokes (cSt).
Relevant Formulas in Science and Mathematics
- Definition of Kinematic Viscosity (Fluid Mechanics): Kinematic viscosity (ν, nu) is defined as the ratio of the dynamic viscosity (μ, mu) to the density (ρ, rho) of the fluid:
ν = μ / ρ. - Reynolds Number (Fluid Mechanics): This dimensionless number is crucial for predicting flow patterns. It is calculated as
Re = (vL) / ν, where 'v' is the fluid velocity, 'L' is a characteristic length, and 'ν' is the kinematic viscosity. A low Reynolds number indicates smooth, laminar flow, while a high Reynolds number indicates chaotic, turbulent flow.
A Deep Dive into Common Kinematic Viscosity Units
- Square meters per second (m²/s): The SI unit of kinematic viscosity.
- Stokes (St): The CGS (centimeter-gram-second) unit, equal to one square centimeter per second (cm²/s). 1 St = 0.0001 m²/s. It is named after George Gabriel Stokes.
- CentiStokes (cSt): The most commonly used unit for kinematic viscosity. 1 Stokes = 100 centiStokes. The kinematic viscosity of water at room temperature is conveniently close to 1 cSt.
- Square feet per second (ft²/s): The Imperial/US customary unit for kinematic viscosity, used in some engineering applications in the United States.