Author(s): Fredrik Huthoff
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Keywords: No Keywords
Abstract: Scaling expressions are derived for equivalent roughness lengths to describe average flow over cylindrical vegetation and two-dimensional dunes. The derivation is based on the assumption that the spatial extent of a flow separation zone behind a bluff body controls flow resistance. A comparison with experimental data available from literature shows that the scaling relations capture the dominant dependencies of the equivalent roughness length. Also, it is shown that the proposed methodology is consistent with the practice of using an equivalent grain roughness for flow over a rough bed. The derived scaling expressions are useful for engineering applications in large-scale flow situations where it is not feasible to make use of more detailed flowmodeling techniques.
Year: 2009