Equivalence between rotational object and pipe flow in mechanism of fluid flow

Abstract

This paper suggests that there is equality in physics between coaxial cylinder and pipe flow on the friction force per unit area. Among rotational machinery, electric motors and turbines for example are common industry which may have concentric shell structure. As the speed of rotating cylinder ascend, particular flow will occur known as Taylor-vortex flow regime beyond certain rotating speed. The major circulation of which has distance at least between coaxial cylinders. This means mass-flow is stirred enough to transport between inner and outer cylinder to emerge universal turbulence representation. It is investigated that stress force within concentric structure is almost the same as of the pipe flow even if the boundaries have various roughness. Consequently, complex behavior of frictional force including bumped surface can be estimated algebraically using Moody diagram.