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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 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.
For instance, a 20% saline (sodium chloride) solution has viscosity over 1.5 times that of pure water, whereas a 20% potassium iodide solution has viscosity about 0.91 times that of pure water. An idealized model of dilute electrolytic solutions leads to the following prediction for the viscosity μ s {\displaystyle \mu _{s}} of a solution: [ 57 ]
Viscoelastic materials have elements of both of these properties and, as such, exhibit time-dependent strain. Whereas elasticity is usually the result of bond stretching along crystallographic planes in an ordered solid, viscosity is the result of the diffusion of atoms or molecules inside an amorphous material. [1]
The viscosity coefficient μ is a property of a Newtonian material that, by definition, does not depend otherwise on v or σ. The strain rate tensor E(p, t) is symmetric by definition, so it has only six linearly independent elements. Therefore, the viscosity tensor μ has only 6 × 9 = 54 degrees of freedom rather than 81. In most fluids the ...
The same goes for shear viscosity. For a Newtonian fluid the shear viscosity is a pure fluid property, but for a non-Newtonian fluid it is not a pure fluid property due to its dependence on the velocity gradient. Neither shear nor volume viscosity are equilibrium parameters or properties, but transport properties.
Relative viscosity (a synonym of "viscosity ratio") is the ratio of the viscosity of a solution to the viscosity of the solvent used (), =. The significance in Relative viscosity is that it can be analyzed the effect a polymer can have on a solution's viscosity such as increasing the solutions viscosity.
A simple and widespread empirical correlation for liquid viscosity is a two-parameter exponential: = / This equation was first proposed in 1913, and is commonly known as the Andrade equation (named after British physicist Edward Andrade). It accurately describes many liquids over a range of temperatures.