LONGITUDINAL DISPERSION FOR FLOW OVER ROUGH BEDS

The longitudinal dispersion coefficient, D sub L, is evaluated on the basis of a one-dimensional analysis as affected by large bed roughness in a laboratory flume. The experimental results have shown that the dimensionless dispersion coefficient, D sub L/Yu*, in which Y is the water depth and u* is the bed shear velocity, is a function of the relative roughness height, Y/h, and the relative roughness spacing, X/Y. It is also found that D sub L/Yu* reaches a maximum value at a roughness density h/X = 0.111. The commonly used equation for estimating the longitudinal dispersion coefficient (D sub L = C Yu*) is also examined. It is found that this straight line relation between D sub L and Yu* is no longer valid of Yu* greater than 0.1 sq ft per sec (0.009 m sq/s).

Media Info

  • Features: Appendices; Figures; References; Tables;
  • Pagination: p. 483-498
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00139191
  • Record Type: Publication
  • Report/Paper Numbers: ASCE #12049
  • Files: TRIS
  • Created Date: Sep 16 1976 12:00AM