Response of Bed Shear Stress in Open-Channel Flow to a Sudden Change in Bed Roughness

Sudden change in bed roughness can occur in many situations in open-channel flows including flow through culverts, flow around bridge piers and abutments, and overtopping of roadways in the floodplain, where bed materials can change abruptly from that of the original riverbed to riprap protection, and vice versa. A sudden change in bed roughness also occurs frequently in the laboratory when soil erosion is studied using a sediment recess in an open-channel flume or water tunnel. In all the above, the bed shear stress is a fundamental hydraulic parameter that must be determined accurately. The proposed research will investigate the evolution of fluid velocity profile and bed shear stress near bed roughness transitions. Velocity measurements will be obtained over smooth-to-rough and rough-to-smooth transitions in an open-channel flume using a Particle Image Velocimetry (PIV) system. The measured data will be used to evaluate different methods for determining the bed shear stress around roughness transition. Bed shear stress will be determined using the channel slope, from the measured velocity profile using the logarithmic law, from the measured Reynolds stress distribution, and from direct measurement of bed shear stress (on a smooth bed) using a hot-film anemometer.


  • English


  • Status: Active
  • Funding: $165537
  • Contract Numbers:


  • Sponsor Organizations:

    Office of the Assistant Secretary for Research and Technology

    University Transportation Centers Program
    Department of Transportation
    Washington, DC  United States  20590
  • Managing Organizations:

    Mountain-Plains Consortium

    North Dakota State University
    Fargo, ND  United States  58108
  • Project Managers:

    Tolliver, Denver

  • Performing Organizations:

    Dept. of Civil and Environmental Engineering

    South Dakota State University
    Brookings, SD  United States 
  • Principal Investigators:

    Ting, Francis

  • Start Date: 20220524
  • Expected Completion Date: 20240731
  • Actual Completion Date: 0
  • USDOT Program: University Transportation Centers Program
  • Source Data: MPC-688

Subject/Index Terms

Filing Info

  • Accession Number: 01848269
  • Record Type: Research project
  • Source Agency: Mountain-Plains Consortium
  • Contract Numbers: 69A3551747108
  • Files: UTC, RIP
  • Created Date: Jun 8 2022 9:04PM