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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.
The centipoise is convenient because the viscosity of water at 20 °C is about 1 cP, and one centipoise is equal to the SI millipascal second (mPa·s). The SI unit of kinematic viscosity is square meter per second (m 2 /s), whereas the CGS unit for kinematic viscosity is the stokes (St, or cm 2 ·s −1 = 0.0001 m 2 ·s −1 ), named after Sir ...
The longer it takes, the higher the viscosity and thus the higher the SAE code. Larger numbers are thicker. J300 specifies a viscosity range for each non-winter grade, with higher grade numbers corresponding to higher viscosities. In addition, a minimum viscosity measured at a high temperature and high-shear rate (HTHS, ASTM D4683) is also ...
The third edition of the IUPAC Green Book, for example, lists Pa⋅s (pascal-second) as the SI-unit for dynamic viscosity, and does not mention the poiseuille. The equivalent CGS unit, the poise , symbol P, is most widely used when reporting viscosity measurements.
The viscosity of a shear thickening – i.e. dilatant – fluid appears to increase when the shear rate increases. Corn starch suspended in water ("oobleck", see below ) is a common example: when stirred slowly it looks milky, when stirred vigorously it feels like a very viscous liquid.
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.
English: Plotting unconventional reservoir types in a plot of viscosity versus permeability to distinguish between resources dominated by capillary versus buoyancy controls - the scheme was created as part of the article defining unconventional reservoirs and was compiled from citations read, principally [1] [2] [3]
Newtonian fluids are the easiest mathematical models of fluids that account for viscosity. While no real fluid fits the definition perfectly, many common liquids and gases, such as water and air, can be assumed to be Newtonian for practical calculations under ordinary conditions.