THE EFFECTS OF SURFACE ROUGHNESS ON THE WAVE FORCES ON A CIRCULAR CYLINDRICAL PILE

Wave tank experiments were performed on a circular cylindrical pile whose outer surface roughness was varied by gluing sand grains of designated size ranges onto its surface. A train of monochromatic waves of a selected length and height combination was sent past the model and recordings were made of the water surface elevation, horizontal force and bending moment time histories. These records were then analyzed using the semi-empirical approach of the Morison to evaluate drag and inertia coefficients. Linear wave theory was used in evaluating the water particle kinematics. The accuracy of the semi-empirical methods was found to be insufficient to measure the effects of surface roughness. However, the measurements of average maximum wave force for each experiment indicated that surface roughness has a definite effect on the magnitude of force as would be expected. If no reduction in the pile force is made to correct for the added increment of pile diameter due to the presence of the sand grains, the overall average increases in the ratio of forces obtained from the experiments using relative roughness of 0.0075, 0.0186 and 0.0361 are 1, 13 and 23 percent, respectively.

  • Corporate Authors:

    Texas A&M University, College Station

    Sea Grant Program, Center for Marine Resources
    College Station, TX  USA  77843
  • Authors:
    • Burton, W J
    • Sorensen, R M
  • Publication Date: 0

Media Info

  • Features: References;
  • Pagination: 137 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00048046
  • Record Type: Publication
  • Source Agency: National Maritime Research Center, Galveston
  • Report/Paper Numbers: 121
  • Files: TRIS
  • Created Date: Oct 31 1973 12:00AM