Bow-wave-like hydraulic jump and horseshoe vortex around an obstacle in a supercritical open channel flow - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Physics of Fluids Année : 2010

Bow-wave-like hydraulic jump and horseshoe vortex around an obstacle in a supercritical open channel flow

Résumé

The objective of the present paper is to characterize the interaction of a supercritical open channel flow with an emerged, rectangular shaped 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 regarding their relative detachment lengths. For high Reynolds numbers (turbulent regime), the detachment length of the hydraulic jump exceeds the one of the horseshoe vortex; this flow type is named "breaking type." Oppositely, for lower Reynolds numbers (laminar regime), the detachment length of the horseshoe vortex exceeds the one of the hydraulic jump, and the flow type is named "separation type." Experimental measurements based on particle deposition and colored streamline deflection are used to detect the location and shape of the detachment curves. We showed that for both flow types, the shape of the hydraulic jump curve is hyperbolic, constrained by two asymptotes following the Froude angle on each side of the obstacle. On the other hand, the shape of the horseshoe vortex curve depends on the flow type; it is hyperbolic in the separation type and elliptic in the breaking type. The dimensional analysis reveals that three parameters can influence the detachment curves: the upstream Froude and Reynolds numbers and the upstream water depth normalized by the obstacle thickness. The influence of these parameters is investigated experimentally on a water table for both flow types.
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Dates et versions

hal-00746687 , version 1 (24-01-2013)

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Emmanuel Mignot, Nicolas Riviere. Bow-wave-like hydraulic jump and horseshoe vortex around an obstacle in a supercritical open channel flow. Physics of Fluids, 2010, 22, pp.117105. ⟨10.1063/1.3505013⟩. ⟨hal-00746687⟩
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