The accurate prediction and measurement of the behavior of a fluid in motion is essential in the design of efficient industrial. The term fluid refers to liquids and gases both of which have viscosity.

A highly viscous fluid will move less readily than a fluid of low viscosity. The same procedure is carried out three times, after which the meantime is determined. The viscosity of a fluid refers to how easily it moves under stress. More is the Friction more is the amount of force required to move the layers this is. The internal forces or Friction of Fluid comes into play when one layer of Fluid is subjected to move over another layer. It is a measure of the internal forces of a Fluid. The time it took for the liquid to flow from the upper mark (b) to the lower mark (a) is recorded using a stopwatch. Viscosity is the tendency of a Fluid to resist any change in its shape or Motion. The water is then drawn up toward limb Y to cross the upper mark “b.” The liquid is then permitted to flow down. Water is initially inserted through limb X into Ostwald’s viscometer. The units of dynamic viscosity are Poise or Pa.s and the dimensions are. They are related via the density of the medium, with.

First, we differentiate between the viscosities, referred to by symbols. We take Ostwald’s viscometer in its dry state. There are several different types of viscosities that one may encounter in fluid dynamics. The procedure to determine the viscosity of liquid using Ostwald’s Viscometer is described below:

In practice, the relative viscosity of liquid with respect to water is determined. With the help of equation (ii), the absolute value of the coefficient of viscosity can be determined. According to Poiseulle’s law, the volume (V) of liquid flowing through a tube having radius ‘r’ and length ‘ l‘ under a difference of pressure at the two ends (p) within time ‘t’ is given by The determination of viscosity of a liquid is generally carried out by Ostwald’s viscometer method whose principle is based on Poiseulle’s law.

Viscosity definition in chemistry