Author(s): Orazio Giustolisi
Linked Author(s): Orazio Giustolisi
Keywords: Corrugated pipes; Artificial macro-roughness; Hyper-turbulent flow
Abstract: Artificially roughened pipe for sewerage systems has been experimentally studied. laboratory tests were aimed at measuring the down-flow scales a different slopes, from 2° to 10°, and at determining the dependence of the roughness coefficient for the particular pipe. It has been observed that Chezy roughness coefficient is a function of the pipe slope, that is, the average velocity of flow, because of the hyper-turbulent flow caused by the vortex generated by the roughness elements distributed along the pipe. The occurrence of a hyper-turbulent flow over a rough pipe confirms the results obtained by H. M. Morris in 1955; in particular, the dependence of the friction factor on the Reynolds number increases in the case of a normal turbulent flow. From a technical viewpoint the abnormal turbulence along the pipe walls generates other dissipations that cause a slowing down of the flow which also is useful in sewer systems installed on sloping soils. Besides, the abnormal intense turbulence at wall should have a positive self-cleaning effect on the pipe.
Year: 2001