Absolute viscosity

Absolute Viscosity is a measure of a fluid's internal resistance to flow. It is often referred to as the fluid's "thickness". The SI unit for absolute viscosity is the pascal-second (Pa·s), although the more common unit is the centipoise (cP).

Definition

Absolute viscosity is defined as the ratio of the shear stress in a fluid to the rate of shear strain. It is a measure of the internal friction in a fluid, or, in other words, the resistance of a fluid to flow. The higher the absolute viscosity, the thicker the fluid and the greater its resistance to flow.

Measurement

The measurement of absolute viscosity is typically done using a viscometer. There are several types of viscometers, including the capillary viscometer, the rotational viscometer, and the falling sphere viscometer. The choice of viscometer depends on the type of fluid being measured and the required accuracy.

Factors affecting absolute viscosity

The absolute viscosity of a fluid is affected by several factors, including temperature, pressure, and the presence of impurities. In general, the absolute viscosity of a fluid decreases with increasing temperature and increases with increasing pressure. The presence of impurities can either increase or decrease the absolute viscosity, depending on the nature of the impurities.

Applications

Absolute viscosity is an important property in many fields, including chemical engineering, mechanical engineering, and medicine. It is used in the design of pumps, pipes, and other fluid handling equipment, and in the formulation of pharmaceuticals, paints, and cosmetics.

See also

• Viscosity
• Dynamic viscosity
• Kinematic viscosity