Author(s): E. Mignot; N. Riviere; N. Gonima
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Keywords: No Keywords
Abstract: The objective of the present paper is to characterize the interaction of a supercritical open channel flow with an emerging obstacle. Upstream from the obstacle, two main flow structures are observed: i) a hydraulic jump in the near-surface region and ii) a horseshoe vortex in the near-bed region. Both flow structures are detached upstream from the obstacle and two main flow types occur with regards to their relative detachment lengths. For uniform upstream flows with high Reynolds numbers, the detachment length of the hydraulic jump exceeds the one of the horseshoe vortex; this flow type is named “Breaking type”. Oppositely, for upstream flows with lower Reynolds numbers, the detachment length of the horseshoe vortex exceeds the one of the hydraulic jump; this flow type is named “Separation type”. The dimensional analysis reveals that three parameters can influence the detachment lengths: the upstream Froude and Reynolds numbers and the obstacle thickness normalized by the upstream water depth. The influence of these parameters is investigated experimentally on a water table for the Separation type.
Year: 2009