Kinematic viscosity is a fundamental physical characteristic of all gas and liquid environments.This figure is crucial in determining the drag of the moving solids and the load that they do experience.It is known that in our world any movement occurs in the air or aqueous medium.This body is always moving on to a force vector which is opposite to the direction of movement of the objects themselves.Accordingly, the higher the kinematic viscosity of the medium, the greater loads experienced solid.What is the nature of the properties of liquids and gases?
Kinematic viscosity, defined as the internal friction is due to momentum transfer agent molecules perpendicular to the motion of its layers having different speeds.For example, in liquids each of the structural units (molecule) surrounded on all sides of her closest neighbors are located at a distance equal to the diameter.Each molecule oscillates around the so-called equilibrium position, but given the momentum from its neighbors, it makes a sharp jump in the direction of oscillation of the new center.A second structural unit of each such substance has time to change his place of residence about a hundred million times, making between jumps from one to hundreds of thousands of hesitation.Of course, the greater the molecular interaction is, the lower the mobility of each structural unit and, consequently, more substance kinematic viscosity.
If any molecule has permanent foreign forces from the adjacent layers, then the particle is in the direction of greater movement for a certain unit of time than the opposite.Therefore, it is transformed into a chaotic wandering orderly movement at a certain speed, depending on the forces acting on it.This inherent viscosity, such as motor oil.It is important, and the fact that the annex to the considered particle external forces do the work of a peculiar apart of the layers through which squeezes the molecule.Such exposure eventually increases the rate of thermal random movement of particles which does not change with time.In other words, it is characterized by a uniform fluid flow, despite the constant influence of external forces in different directions as they are balanced by internal resistance of the layers of matter, what exactly defines the kinematic viscosity.
With increasing temperature begins to increase the mobility of the molecules, which leads to a certain decrease in the resistance layers of matter, as in any heated substance created more favorable conditions for the free movement of particles in the direction of the applied force.This can be compared with the way a person is much easier to squeeze through the crowd moving erratically than fixed.A significant indicator of the kinematic viscosity, measured in Stokes or Pascal seconds have polymer solutions.This is due to the presence in their structure rigidly connected to the long molecular chains.But when the temperature rises outside their viscosity decreases rapidly.During extrusion of plastic products it threadlike, intricately intertwined molecules forcibly taking the new position.
viscosity of the gas at a temperature of 20 ° C and atmospheric pressure is of the order of 101.3 Pa * s 10-5Pa.For example, the kinematic viscosity of air, helium, oxygen and hydrogen under such conditions will be equal to 1.82 * 10-5, respectively;1.96 * 10-5;2.02 * 10-5;0.88 * 10-5 Pa * s.A liquid helium in general has a wonderful property of superfluidity.This phenomenon, discovered by Academician PLKapitsa, is that the active metal is in a state of aggregation is almost no viscosity.For him, this figure is almost equal to zero.
