Author(s): Faruk Bhuiyan; Nallamuthu Rajaratnam; David Z. Zhu
Keywords: Densimetric particle Froude number; open channel flow; sediment deposition; sediment plume; turbulent flow; underwater mound
Abstract: The development of large sediment mounds formed by continuous release of coarse materials in flowing water is reported. Growths of mound height, longitudinal profile and areal extent were examined for three flow conditions. Longitudinal profiles of depositions during the development phase of the mounds were approximately similar, and they can be expressed by an exponential function if scaled with the maximum height and a width parameter. From observations, it appeared that the mound peak shifted gradually towards upstream and followed the outer part of the sediment plume. The heap growth can be expressed as a function of buoyancy flux due to sediment disposal, flow momentum and densimetric particle Froude number. The deposition height increased with normalized time until reaching close to the water surface. The width and area developed faster with normalized time than the height. The deposition area with coarse sediment was characterized by a downstream tail and fin-like extensions on the sides which differed from observations in previous experiments with fine sand.