Description
When an obstacle is placed in a flow on an erodible bed, a scour hole forms at the footing of the obstacle. On river beds, this phenomenon typically occurs in the vicinity of bridge piers and/or abutments, often leading to the structure collapse.
The movie shows the scour activation at a rectangular abutment (vertical plate). The experiment was performed in the Politecnico di Milano, in a pressurized duct filled with plastic sediments. The arrows superimposed to the movie of the sediment motion are proportional to the instantaneous solid discharge per unit width. The solid discharge was measured by image processing, evaluating separately the concentration and the velocity of the moving grains.
Additional notes
More movies can be found on the web site of the Hydraulic Engineering Dept. of the Politecnico di Milano:
http://www.diiar.polimi.it/idra/progetto.asp?id=5.
