Session

Session 10 2022

Start Date

10-27-2022 12:00 AM

Abstract

Along Australian inland waterways, a number of man-made horseshoe obstacles were built for centuries. The permanent structures interacted with the streamflow across a wide range of water discharges including when they are fully-submerged. Their use ranged from water holes and fish trap at low to moderate flows, to large bed roughness and turbulent manipulation at large water discharges. The aim of the study was to gain a sound physical understanding of the hydraulic operation of horseshoe obstacle across a broad range of submergence ratio, ranging from low flows and emergent obstacle to major floods with fully-submerged structures. In this laboratory study, the physical modelling of permeable horseshoe obstacle was undertaken under controlled flow conditions, based upon a Froude similitude. Two physical models were built corresponding to a 5:1 and 20:1 geometric scaling ratio for typical riverine structures. The scale models were 3D-printed with random pattern and a porosity of 0.27, close to the porosity of rockfill material. The physical observations included visual observations, three-dimensional free-surface profiles and detailed velocity measurements. The physical observations showed a broad range of flow patterns, depending upon the submergence ratio. The porosity of the obstacle facilitated some interactions between the seepage and recirculation region, leading to changes in the wake region and its turbulence, compared to a impervious obstacle with the same shape.

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Oct 27th, 12:00 AM

Hydrodynamics of Permeable Horseshoe Obstacle in Fluvial Environment: A Physical Modelling

Along Australian inland waterways, a number of man-made horseshoe obstacles were built for centuries. The permanent structures interacted with the streamflow across a wide range of water discharges including when they are fully-submerged. Their use ranged from water holes and fish trap at low to moderate flows, to large bed roughness and turbulent manipulation at large water discharges. The aim of the study was to gain a sound physical understanding of the hydraulic operation of horseshoe obstacle across a broad range of submergence ratio, ranging from low flows and emergent obstacle to major floods with fully-submerged structures. In this laboratory study, the physical modelling of permeable horseshoe obstacle was undertaken under controlled flow conditions, based upon a Froude similitude. Two physical models were built corresponding to a 5:1 and 20:1 geometric scaling ratio for typical riverine structures. The scale models were 3D-printed with random pattern and a porosity of 0.27, close to the porosity of rockfill material. The physical observations included visual observations, three-dimensional free-surface profiles and detailed velocity measurements. The physical observations showed a broad range of flow patterns, depending upon the submergence ratio. The porosity of the obstacle facilitated some interactions between the seepage and recirculation region, leading to changes in the wake region and its turbulence, compared to a impervious obstacle with the same shape.