Relative roughness is a measure of the surface roughness of pipe surfaces. It is the size of the roughness scaled by the diameter of the pipe or duct. Rel Roughness=e/D; where e is the measurement of the surface roughness and D is the diameter of the pipe. It is mainly used for calculating head losses in piping systems.

surface roughness tester is the machine which used to measure the roughness of the surface using probes... roughness is nothing but the frictional force applied by the surface to the adjacent surface.. if roughness increases the amount of frictional force increases..

The Absolute roughness, e, of copper is 1.5 microns The relative roughness is just e/D

The director of Necessary Roughness was Stan Dragoti.

The difference between roughness and flatness is that one, flatness, is the shape of an object. Roughness is the surface or texture of an object.