Turbulence intensity and the friction factor for smooth- and rough-wall pipe flow

TL;DR

This paper compares turbulence intensity profiles in smooth and rough pipe flows, analyzing their development and relation to the friction factor, and how these profiles scale with Reynolds number in different flow regimes.

Contribution

It provides a detailed comparison of turbulence intensity profiles for smooth and rough pipes and quantifies their relationship with the friction factor across flow regimes.

Findings

Turbulence intensity profiles develop sequentially from wall to axis during transition.

Scaling of turbulence intensity with Reynolds number differs between smooth and rough walls.

A quantitative relationship between turbulence intensity and friction factor is established.

Abstract

Turbulence intensity profiles are compared for smooth- and rough-wall pipe flow measurements made in the Princeton Superpipe. The profile development in the transition from hydraulically smooth to fully rough flow displays a propagating sequence from the pipe wall towards the pipe axis. The scaling of turbulence intensity with Reynolds number shows that the smooth- and rough wall level deviates with increasing Reynolds number. We quantify the correspondence between turbulence intensity and the friction factor.