What is the term used to describe resistance to flow of water in pipes?

The term used to describe the resistance to the flow of water in pipes is friction. In fluid dynamics, friction refers to the internal resistance that occurs as water flows through the pipe. This resistance is caused by the interaction between the water and the surface of the pipe, as well as the viscosity of the water itself.

As water moves, it tends to lose energy due to this frictional force, which can result in a pressure drop along the length of the pipe. This pressure loss is integral to the design and analysis of water distribution systems, where engineers must account for friction when calculating flow rates and determining the appropriate pipe sizes.

Understanding friction is crucial for ensuring efficient water distribution, as it directly influences the required pump energy and overall system performance. In contrast, concepts like pressure loss and dynamic loss relate to the effects of friction but do not define the resistance itself. Velocity head is concerned with kinetic energy associated with flow velocity, but it is not a term that describes resistance to flow.