Viscosity of Fluid

Viscosity measures how a fluid resists flowing due to internal friction when layers of the fluid move past each other.

For example, honey flows slowly because it has high viscosity, while water flows easily with low viscosity.

There are two main types of viscosity: dynamic and kinematic. Dynamic viscosity measures the force needed to move one fluid layer over another.

For instance, when stirred, honey resists the spoon more than water. Kinematic viscosity is the ratio of a fluid's dynamic viscosity to its density, describing how the fluid spreads under gravity.

Most common fluids, such as water and air, have a constant viscosity regardless of the applied force.

However, some fluids, like ketchup, change their viscosity depending on the force applied; ketchup flows more easily when the bottle is shaken.

Temperature significantly affects viscosity, crucial in designing pipelines, where the oil must flow smoothly.

In contrast, warm air in a sauna demonstrates how higher temperatures increase the viscosity of gases.