It is also possible for some samples to display Newtonian behavior at low shear rates with a plateau known as the zero shear viscosity region. For example, low concentration protein or polymer solutions might display a constant viscosity regardless of shear rate. However, it is also possible to have Newtonian behavior with large anisotropic molecules. Newtonian fluids are normally comprised of small isotropic (symmetric in shape and properties) molecules that are not oriented by flow. A great example of this kind of behavior is mayonnaise. These are strictly non-Newtonian, but once the flow starts they behave essentially as Newtonian fluids (i.e. viscosity is independent of the rate of shear).Īn exception to the rule is Bingham plastics, which are fluids that require a minimum stress to be applied before they flow. This means that the viscosity of Newtonian fluids will remain a constant (see Figure 2) no matter how fast they are forced to flow through a pipe or channel (i.e. As a result, if we look at a plot of shear stress versus shear rate (See Figure 1) we can see a linear increase in stress with increasing shear rates, where the slope is given by the viscosity of the fluid. For those fluids viscosity is only dependent on temperature. Some examples of Newtonian fluids include water, organic solvents, and honey. This relationship is now known as Newton's Law of Viscosity, where the proportionality constant η is the viscosity of the fluid:
Newtonian fluids are named after Sir Issac Newton (1642 - 1726) who described the flow behavior of fluids with a simple linear relation between shear stress and shear rate. Each unique material has its own behavior when subjected to flow, deformation or stress.ĭepending on their viscosity behavior as a function of shear rate, stress, deformation history., fluids are characterized as Newtonian or non-Newtonian.
However, fluid characterization is far more deep and complex than what is usually expected. If you are on this site, you probably have a general idea about what is viscosity and how important it is in the development of any application that involves fluid flow. Specific isobar heat capacity cp steam, specific isochor heat capacity cv steam, adiabatic exponent or isentropic exponent kappa steam, thermic conductivity steam, speed of sound steam.Viscosity of Newtonian and non-Newtonian Fluids Specific isobar heat capacity cp water, specific isochor heat capacity cv water, thermic conductivity water, speed of sound water.ĭensity steam, dynamic viscosity steam, kinematic viscosity steam, specific inner energy steam, specific enthalpy steam, specific entropy steam, The following thermodynamic properties are calculated:ĭensity water, dynamic viscosity water, kinematic viscosity water, specific inner energy water, specific enthalpy water, specific entropy water, Online calculation of properties of water and steamĮmail: scientific and engineering data onlineĬalculation of thermodynamic properties of water Pressure:Ĭalculation of thermodynamic properties of overheated steamĬalculation of thermodynamic properties of saturated steam Pressure:
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