Author(s): Bommanna Krishnappan; Ian Ppo; Niels Madsen; Robert Stephens
Linked Author(s):
Keywords: Stability; Sediment deposits; Rotating circular flume; Critical shear stress for erosion; Erosion rate; In-situ erosion flume; Bed shear stress
Abstract: Erosional stability of sediment deposits in Hamilton Harbour, Ontario, Canada was studied in a rotating circular flume. The circular flume used measures 5. 0 m in mean diameter, 30 cm in width and 30 cm in depth. It is supported on a rotating platform, which is 7. 0 m in diameter. A counter rotating annular lid fits inside the flume with close tolerance and makes contact with the water surface within the flume. The flume and the lid are rotated in opposite direction to generate turbulent shear flows. Sediment cores from the Harbour were collected using a coring device developed specifically for collecting a layer of sediment near the sediment-water interface, and were tested in the flume by mounting them in a special device that exposed the sediment to the flow near the flume bed. Critical shear stress required to erode the top layer of sediment and the erosion rate were obtained by operating the flume at different bed shear stress levels until the erosion of the sediment layer was initiated and continued. The critical bed shear stress and the erosion rate values obtained from the flume deviated from a set of measurements carried out using an in-situ erosion flume carried out in a previous study. Possible explanations for the discrepancy are explored.
Year: 2007