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

The term that describes the resistance to the flow of water in pipes is friction. When water moves through pipes, it encounters resistance due to the interaction between the water and the surface of the pipe. This resistance is primarily attributable to the roughness of the pipe material, the shape of the pipe, and the viscosity of the water itself.

As water flows, friction creates a loss of energy, which is manifested as a pressure drop along the length of the pipe. This is an important concept in fluid dynamics and water distribution systems because understanding and managing friction loss is crucial for ensuring efficient water transport and adequate system design.

While pressure loss, velocity head, and dynamic loss all relate to the flow of fluids in some manner, none specifically refer to the resistance encountered during flow. Pressure loss can occur due to friction but also includes other factors like fittings and bends in the pipeline system. Velocity head pertains to the kinetic energy per unit weight of fluid due to its velocity, and dynamic loss encompasses a broader range of losses in a fluid system, including friction. However, friction is the specific term that isolates the resistance encountered in pipes.