![]() Though it was developed nearly 400 years ago, many of the basic tenets of classical mechanics hold for common situations (excluding microscopic particle dynamics, high-velocity motion, and large-scale mechanics). Classical mechanics concerns itself with the mathematical description of the motion of physical bodies, tying together the concepts of force, momentum, velocity, and energy to describe the behaviour of macroscopic objects. Fluids that behave in this way are called Newtonian fluids in honour of Sir Isaac Newton, who first formulated this mathematical description of viscosity.Classical mechanics, the father of physics and perhaps of scientific thought, was initially developed in the 1600s by the famous natural philosophers (the codename for ’physicists’) of the 17th century such as Isaac Newton building on the data and observations of astronomers including Tycho Brahe, Galileo, and Johannes Kepler. This constant is called the dynamic, or absolute, viscosity and often simply the viscosity. In other words, the shear stress divided by the rate of shear strain is constant for a given fluid at a fixed temperature. Measuring of Kinematic Viscosity: There are various methods for determining the kinematic viscosity of a fluid, but the capillary tube viscometer is the most often used. A dynamic viscosity is defined as the density of a fluid. It controls the liquid flow in such processes as spraying, injection molding, and surface coating.įor many fluids the tangential, or shearing, stress that causes flow is directly proportional to the rate of shear strain, or rate of deformation, that results. V / v is the equation to solve for where v is the kinematic viscosity. Viscosity is a major factor in determining the forces that must be overcome when fluids are used in lubrication and transported in pipelines. Because part of a fluid that is forced to move carries along to some extent adjacent parts, viscosity may be thought of as internal friction between the molecules such friction opposes the development of velocity differences within a fluid. Molasses, for example, has a greater viscosity than water. Correlations for the calculation of viscosity can be expected to evaluate viscosity for temperatures ranging from 35 to 300☏. This parameter is required for conditions ranging from surface gathering systems to the reservoir. The reciprocal of the viscosity is called the fluidity, a measure of the ease of flow. Any calculation involving the movement of fluids requires a value of viscosity. ![]() Viscosity, resistance of a fluid (liquid or gas) to a change in shape, or movement of neighbouring portions relative to one another. Thus, upon heating, liquids flow more easily, whereas gases flow more sluggishly. The viscosity of liquids decreases rapidly with an increase in temperature, and the viscosity of gases increases with an increase in temperature.
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