Bed Forms Due to a Fluid Stream

by Harry M. Hill,

Serial Information: Journal of the Hydraulics Division, 1966, Vol. 92, Issue 2, Pg. 127-143

Document Type: Journal Paper


A general investigation of the occurrence of bed forms is reported. A relationship is determined for finding the point at which ripples would replace the flat bed. From the Bagnold number, the number with which the ratio of shear stress to dispersive pressure varied, the writer reasons that when this ration became greater than the coefficient of friction of sand at rest the system becomes unstable. The data available generally support this assumption, however, there is little data for this condition because the flat bed is usually displaced by dunes. An M versus ∖a/ curve was used to determine the point at which the flat bed ceased to exist because of dune formation. An empirical relationship for determining the point at which the flat bed is replaced by dunes was found to be applicable for all the experiments in which sand was used as the bed material. The factors affecting the collision region were investigated. Further experiments are proposed to investigate the M versus ∖a/ function.

Subject Headings: High-rise buildings | Dunes | Bed materials | Bed forms | Fluidized bed technology | Shear stress | Soil pressure | Sandy soils

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