Author(s): A. Recking; D. Rickenmann
Linked Author(s):
Keywords: Flow resistance; Gravel Bed River
Abstract: Some flow resistance equations can be used with no at-a-site calibration. The more popular ones are the logarithmic equations derived from the law of the wall. It can be shown that the predictions using these flow depth based equations improves if the equations are solved iteratively from the known discharge. However, during the last decade, many people have tried to link directly the mean flow velocity to the flow discharge. These equations are of interest because they are easy to use, with no iteration. In this paper we compare logarithmic and q-based equations using a large data set constituted of 3318 field measurements covering a wide range of slope, grain diameter and discharge. The tests have shown that whereas some logarithmic equations are efficient for a range of flow conditions, the q-based equations appear to have a more general validity over the entire range of examined flow conditions.
Year: 2011