Hydro-suctioning of Sediment: Scour Profile Investigation and Flow field Visualization Using CFD.
Abstract
Hydro-suctioning is a sediment removal process in which a suction pipe is placed vertically on/above the sediment bed. With the commencement of hydro-suctioning, movement of sediment below the suction pipe starts, forming a scour hole in the sediment surface. Sediment removal continues till an equilibrium is attended; after that, there will be no removal. Sediment transportation depends on the size of the particle, diameter and inlet depth of suction pipe, and the strength of the flow.
This investigation aims to study the scour profile formation during hydro-suctioning removal of sediment. Suction pipe diameters (D) of 5.08 cm, 7.62 cm, 10.16 cm, 12.7 cm, and 15.24 cm, placed at suction inlet depths (C) of 1.5 cm and 3 cm above the sediment surface, were used in this study. A series of experiments were performed under discharge (Q) ranging from m3/s to m3/s. Sediment of a median size (d50) of 0.33 mm was used for this investigation. A total of 70 readings of scour profiles were taken during this investigation. Flow field during hydro-suctioning, was also visualized using CFD in Ansys Fluent. The scour profile is semi-circular shaped mostly for all cases, but a small hump at the center of the scour profile is also seen for small discharges. With other parameters being constant, the depth of scour profile increases with discharge up to D = 10.16 cm. After that, any further increase in D leads to a decrease in scour profile. At a constant value of C, dimensionless maximum scour depth (dsm/D) increases with increasing Froud number. With increase in dimensionless suction depth (C/D), dsm/D also increases with a kink at C/D = 0.15. Flow field shows that maximum velocity is at the mouth of suction inlet depth, and it decreases while going away from the mouth.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFMEP55D0850J