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Other examples include many polymer solutions (which exhibit the Weissenberg effect), molten polymers, many solid suspensions, blood, and most highly viscous fluids. Newtonian fluids are named after Isaac Newton, who first used the differential equation to postulate the relation between the shear strain rate and shear stress for such fluids.
In a fluid mixture like a petroleum gas or oil there are lots of molecule types, and within this mixture there are families of molecule types (i.e. groups of fluid components). The simplest group is the n-alkanes which are long chains of CH 2-elements. The more CH 2-elements, or carbon atoms, the longer molecule. Critical viscosity and critical ...
The viscous behavior of a liquid can be either Newtonian or non-Newtonian. A Newtonian liquid exhibits a linear strain/stress curve, meaning its viscosity is independent of time, shear rate, or shear-rate history. Examples of Newtonian liquids include water, glycerin, motor oil, honey, or mercury. A non-Newtonian liquid is one where the ...
For example, for a Hookean elastic solid, the relaxation time t c will be infinite and it will vanish for a Newtonian viscous fluid. For liquid water, t c is typically 10 −12 s, for lubricating oils passing through gear teeth at high pressure it is of the order of 10 −6 s and for polymers undergoing plastics processing, the relaxation time ...
Figure 1. Bingham Plastic flow as described by Bingham. Figure 1 shows a graph of the behaviour of an ordinary viscous (or Newtonian) fluid in red, for example in a pipe. If the pressure at one end of a pipe is increased this produces a stress on the fluid tending to make it move (called the shear stress) and the volumetric flow rate increases proportionally.
Some non-Newtonian fluids with shear-independent viscosity, however, still exhibit normal stress-differences or other non-Newtonian behavior. In a Newtonian fluid, the relation between the shear stress and the shear rate is linear, passing through the origin, the constant of proportionality being the coefficient of viscosity. In a non-Newtonian ...
Let’s talk science: A non-Newtonian fluid is defined as a liquid that does not follow Newton’s law of viscosity. Ultimately, a non-Newtonian fluid will change under force to be either more ...
An example of such a procedure is the Sutherland approach for the single-component gas, discussed above. For gas mixtures consisting of simple molecules, Revised Enskog Theory has been shown to accurately represent both the density- and temperature dependence of the viscosity over a wide range of conditions. [55] [53]