Newtonian liquid is any fluid substance having the constant viscosity not dependent on external tension which influences it. One of examples is water. At non-Newtonian liquids viscosity will change and directly depends on the speed of the movement.
What is Newtonian liquids?
Examples of Newtonian liquids are suspensions, suspensions, gels and colloids. The main feature of such substances is that the viscosity for them is a constant and does not change concerning deformation speed.
Speed of deformation is a relative tension which appears at liquid at its movement. The majority of liquids — Newtonian and are applicable Bernoulli's equations for laminar and turbulent flows to them.
Deformation speed
Liquids, sensitive to shift, is more fluid. Speed of shift or a gap between substance and walls of a vessel, as a rule, not really influence this parameter and they can be neglected. The value of speed of deformation is known for all materials and is tabular value. In certain cases it, however, can change. For example, if liquid represents an emulsion which is applied on a film for the photo, then even insignificant defects can lead to emergence of spots, and the final product will not have necessary qualities.
Various liquids and their viscosity
In Newtonian liquids, the viscosity does not depend on shift speed. However for some of them, the viscosity changes depending on time. It is shown on change of pressure in the tank or a pipe. Such liquids are called dilatantny or thixotropic. For latent liquids tension of shift grows always as their viscosity and increase in speed of shift are interconnected. For thixotropic liquids these parameters can chaotically change. Speed of deformation cannot quickly increase with decrease in viscosity. Therefore the speed of the movement of particles of substance can increase, decrease or remain the same. Everything depends on liquid type. However the speed of deformation has property to decrease. It means that pump power will also decrease together with substance movement speed. In other words, liquid at first is knitting, but as soon as it begins to move, becomes less viscous. It means that less energy for its transfer is required. The neglect the engine capacity of the pump is the widespread phenomenon. This value is usually calculated for viscosity of liquid in the movement. In practice much more powerful motor is necessary to force substance to move. Ketchup is one of examples of such phenomenon. For this reason we have to stir up a bottle that it began to flow. As soon as process began, it proceeds quicker.