Search results
Results From The WOW.Com Content Network
The proportionality factor is the dynamic viscosity of the fluid, often simply referred to as the viscosity. It is denoted by the Greek letter mu ( μ ). The dynamic viscosity has the dimensions ( m a s s / l e n g t h ) / t i m e {\displaystyle \mathrm {(mass/length)/time} } , therefore resulting in the SI units and the derived units :
Consequently, if a liquid has dynamic viscosity of n centiPoise, and its density is not too different from that of water, then its kinematic viscosity is around n centiStokes. For gas, the dynamic viscosity is usually in the range of 10 to 20 microPascal-seconds, or 0.01 to 0.02 centiPoise. The density is usually on the order of 0.5 to 5 kg/m^3.
Here dynamic viscosity is denoted by and kinematic viscosity by . The formulas given are valid only for an absolute temperature scale; therefore, unless stated otherwise temperatures are in kelvins .
A built-in density measurement based on the oscillating U-tube principle allows the determination of kinematic viscosity from the measured dynamic viscosity employing the relation =, where: ν is the kinematic viscosity (mm 2 /s), η is the dynamic viscosity (mPa·s), ρ is the density (g/cm 3).
The CGS unit of kinematic viscosity was named "stokes ... the excess force F e due to the difference between the weight and ... μ is the dynamic viscosity [kg/(m•s ...
μ is the dynamic viscosity of the fluid (Pa·s or N·s/m 2 or kg/(m·s)) ν is the kinematic viscosity of the fluid (m 2 /s). The Brezina equation. The Reynolds number can be defined for several different situations where a fluid is in relative motion to a surface.
Dimensionless numbers (or characteristic numbers) have an important role in analyzing the behavior of fluids and their flow as well as in other transport phenomena. [1] They include the Reynolds and the Mach numbers, which describe as ratios the relative magnitude of fluid and physical system characteristics, such as density, viscosity, speed of sound, and flow speed.
The shear viscosity (or viscosity, in short) of a fluid is a material property that describes the friction between internal neighboring fluid surfaces (or sheets) flowing with different fluid velocities. This friction is the effect of (linear) momentum exchange caused by molecules with sufficient energy to move (or "to jump") between these ...