SECOND ANNUAL REPORT USE OF LARGE ROUGHNESS ELEMENTS FOR HYDRAULIC ENERGY DISSIPATION

RESULTS OF EXPERIMENTS DEALING WITH THE UTILIZATION OF SIMPLE TRANSVERSE ROUGHNESS ELEMENTS FOR THE PURPOSE OF DISSIPATING ENERGY IN SMALL STRUCTURES SUCH AS HIGHWAY CULVERTS AND DRAINAGE DITCHES HAVE BEEN REPORTED PREVIOUSLY IN THE FIRST ANNUAL REPORT OF THIS PROJECT. AN EXTENSION OF THE ABOVE-MENTIONED EXPERIMENTS HAS BEEN CARRIED OUT AND THE RESULTS ARE REPORTED HEREIN AS A SUPPLEMENT TO THE FIRST ANNUAL REPORT. THE EXTENDED PORTION OF THE INVESTIGATION INCLUDES A STUDY OF THE EFFECT OF VARIOUS SHAPES OF TRANSVERSE BARS ON THE DEVELOPMENT OF FLOW REGIMES AND THE SELECTION OF THE TRIANGULAR-TOP ELEMENT AS AN OPTIMUM SHAPE; A STUDY OF THE MINIMUM LENGTH OF CHANNEL NECESSARY TO DEVELOP APPROXIMATELY UNIFORM TUMBLING FLOW THE ROUGHNESS ELEMENTS, AND AN ATTEMPT TO DEFINE MORE STRAIGHT-FORWARD DESIGN PROCEDURES THAN HAVE PREVIOUSLY BEEN DESCRIBED. QUALITATIVE RECOMMENDATIONS ARE PRESENTED FOR THE MINIMUM LENGTH OF CHANNEL. PREDICTION EQUATIONS ARE DEVELOPED FOR THE DRAG FORCE AND DRAG COEFFICIENT FOR THE TRIANGULAR-TOP ROUGHNESS ELEMENT AND THEY ARE COMPARED WITH THE CORRESPONDING EQUATIONS FOR THE SQUARE ROUGHNESS ELEMENT. COMPLETE DESIGN PROCEDURES ARE SET FORTH FOR THE USE OF SQUARE TRANSVERSE ROUGHNESS BARS INCLUDING AN EQUATION WHICH CAN BE USED FOR APPROXIMATE DESIGN FOR CASES WHICH FALL OUTSIDE THE EXPERIMENTAL RANGE OF APPLICABILITY. A SUMMARY OF EXPERIMENTAL DATA IS INCLUDED IN THE APPENDIX FOR RECTANGULAR CHANNELS ONLY. /AUTHOR/

  • Supplemental Notes:
    • Hpr, Hps 2768
  • Corporate Authors:

    Virginia Polytechnic Institute and State University, Blacksburg

    Virginia Tech Transportation Institute
    3500 Transportation Research Plaza
    Blacksburg, VA  United States  24061
  • Authors:
    • Jones, J S
    • Chiang, T T
    • Younkin, L M
  • Publication Date: 1965-5

Subject/Index Terms

Filing Info

  • Accession Number: 00203954
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Apr 1 1994 12:00AM