Types of Forces in Fluids

The following are the two types of forces between the molecules:

1. Cohesive forces: Cohesive forces are attractive forces that exist between molecules of the same substance. So, cohesive forces are the main cause of viscosity.

2. Adhesive forces: These are attractive forces between unlike molecules.

An object travels in a fluid it loses its energy to overcome the fluid Friction. The shape of an object plays an important role in increasing or decreasing the fluid friction when it travels along with it.

• Ships and boats have a particular shape that allows them to resist fluid Friction.
• Birds and airplanes have a specific shape that allows them to fly in the air.
• Fishes also have a specific shape such as a tail and fins that allow them to swim continuously in water and even prevent the loss of energy due to fluid Friction.
• The designs of vehicles are made in such a way that they encounter the least fluid friction while traveling to ensure proper usage and movement of them.
• To avoid fluid friction the swimsuits are designed accordingly for a smoother flow.

Fluid friction occurs between fluid layers that are moving relative to each other. This internal resistance to flow is called viscosity or viscous drag or fluid friction. In normal terms, the viscosity of a fluid is described as its “thickness” of the fluid. Thus, water is “thin”, having a lower viscosity, while honey is “thick”, having a higher viscosity. The less viscous the fluid, the greater its ease of deformation or movement.

All real fluids (except superfluids) offer some resistance to shearing and therefore are viscous. Although the term “fluid” includes both the liquid and gas phases, in common usage, “fluid” is often used synonymously with “liquid”. Liquids and gases are called fluids because they can be made to flow or move. In any fluid, the molecules themselves are in constant, random motion, colliding with each other and with the walls of any container. In this article, we will learn in detail about fluid friction, its properties, example and more.