EFFECTIVE HYDRAULIC ROUGHNESS FOR CHANNELS HAVING BED ROUGHNESS DIFFERENT FROM BANK ROUGHNESS: A STATE OF THE ART REPORT

The report summarizes two numerical studies, one laboratory experimental study, and one analytical study of flow resistance in rectangular channels having one type or degree of boundary roughness on the bed and a second type or degree of roughness on the sidewalls. The numerical study showed that usual procedures for estimating resistance coefficients for channels of this type are not adequate. The laboratory study indicated that the relations between the effective Manning's n, the sidewall Manning's n, the bed Manning's n, and the channel geometry could be established empirically by extensive laboratory testing. The analytical study proved that laboratory studies using a smooth surface for one of its boundaries had little application to design problems. It also showed that the best solution to the problem probably would result by use of hydraulic roughness values to describe the boundary surfaces. The study showed that relatively large errors in estimating the hydraulic roughness effect only minor errors in capacity design. (Author)

• Authors:
  • Cox, R G
• Publication Date: 1973-2

Media Info

• Pagination: 64 p.
• Serial:
  • Waterways Experiment Station

Subject/Index Terms

• TRT Terms: Channel flow; Hydrodynamics; Roughness; Skin resistance
• Uncontrolled Terms: Open channel flow
• Old TRIS Terms: Hydrodynamic roughness
• Subject Areas: Hydraulics and Hydrology; Marine Transportation; Terminals and Facilities;

Filing Info

• Accession Number: 00044699
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: AEWES-Misc-Pap-H732 Final Rpt
• Files: TRIS
• Created Date: Jul 31 1973 12:00AM