Author(s): Graeme M. Smart
Linked Author(s): Graeme M. Smart
Keywords: Flow resistance; High relative roughness; Hydraulic radius; In-situ roughness
Abstract: For rough beds, the parameter of depth or hydraulic radius is difficult to define or measure. Volumetric hydraulic radius R is shown to be more suitable for use with the 2D bed shear stress equation. An investigation of the relation between R and depth when water level is below the tops of bed particles was carried out using digital elevation models (DEMs) of actual channel bed surfaces. For the water worked beds, a simple relationship was found and surface standard deviation dz was one third of the distance from mean bed level to the tops of roughness elements. A simple sand spreading technique is proposed for measuring R and dz.
Year: 2001