Experimentally determined hydraulic roughness for a uniformly roughened rectangular open channel.

摘要

The motivation for this study was a need to find the best method to quantify the hydraulic roughness of a rectangular open channel flume uniformly roughened using various materials to line the flume. It was also hoped that a more accurate method of quantifying the hydraulic roughness could be found. Commonly used measures of hydraulic roughness, such as Manning's n or Darcy-Weisbach f, vary with flow parameters such as the Reynolds number and the hydraulic radius.; In the study flume, the Darcy-Weisbach f was also found to vary with the Froude number. A new method of parameterizing f for use in average velocity formulas, using a combination of the Reynolds and Froude numbers was discovered. This is significant because the Froude effects are not accounted for in any formulas enjoying widespread use.