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The density is usually on the order of 1000 kg/m^3, i.e. that of water. 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 ...
The SI unit of dynamic viscosity is the newton-second per square meter (N·s/m 2), also frequently expressed in the equivalent forms pascal-second (Pa·s), kilogram per meter per second (kg·m −1 ·s −1) and poiseuille (Pl). The CGS unit is the poise (P, or g·cm −1 ·s −1 = 0.1 Pa·s), [28] named after Jean Léonard Marie Poiseuille.
The poiseuille (symbol Pl) has been proposed as a derived SI unit of dynamic viscosity, [1] named after the French physicist Jean Léonard Marie Poiseuille (1797–1869).. In practice the unit has never been widely accepted and most international standards bodies do not include the poiseuille in their list of units.
The poise is often used with the metric prefix centi-because the viscosity of water at 20 °C (standard conditions for temperature and pressure) is almost exactly 1 centipoise. [3] A centipoise is one hundredth of a poise, or one millipascal-second (mPa⋅s) in SI units (1 cP = 10 −3 Pa⋅s = 1 mPa⋅s). [4] The CGS symbol for the centipoise ...
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.
This allows to take into account the effect of temperature on the viscosity of the fluid flowing though the porous medium and to address other fluids than pure water, e.g., concentrated brines, petroleum, or organic solvents. Given the value of hydraulic conductivity for a studied system, the permeability can be calculated as follows:
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 dilute gas viscosity contribution to the total viscosity of a fluid will only be important when predicting the viscosity of vapors at low pressures or the viscosity of dense fluids at high temperatures. The viscosity model for dilute gas, that is shown above, is widely used throughout the industry and applied science communities.