BOUNDARY EFFECTS OF UNIFORM SIZE ROUGHNESS ELEMENTS IN TWO-DIMENSIONAL FLOW IN OPEN CHANNELS

Tests were conducted to investigate the characteristics of the vertical velocity distribution in flow in wide channels with large relative roughness. The study was basically a two-dimensional investigation of the boundary roughness effects in turbulent flow. The investigation was conducted in a 48-ft-long, 2-1/2-ft-wide flume with 1/8-, 1/2-, 3/4-, and 1-in. crushed limestone and 34-in. concrete cubes as the boundary roughness. Results indicate that the root-mean-square value of the boundary roughness heights is related to the Nikuradse equivalent sand grain roughness and that the root-mean-square value can be treated as a roughness parameter for boundaries of densely spaced irregular, randomly placed roughness elements of uniform size. Appendix A includes the experimental data. Appendix B describes the special instrumentation used for measuring the vertical velocity profiles within the flow. (Author)

• Corporate Authors:

  U.S. Army Waterways Experiment Station

  3909 Halls Ferry Road
  Vicksburg, MS  United States  39180-6199
• Authors:
  • Brown, B J
  • Chu, Y H
• Publication Date: 1968-12

Media Info

• Pagination: 72 p.

Subject/Index Terms

• TRT Terms: Boundary layer; Channel flow; Hydrodynamics; Roughness; Turbulence; Turbulent boundary layer; Velocity
• Uncontrolled Terms: Open channel flow
• Old TRIS Terms: Hydrodynamic roughness; Velocity profiles
• Subject Areas: Design; Hydraulics and Hydrology; Marine Transportation; Terminals and Facilities;

Filing Info

• Accession Number: 00019399
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: AEWES-MiscPaperH68-5
• Files: TRIS
• Created Date: Nov 19 1971 12:00AM