Distributions of flow velocities on the length of local scour in downstream on weir model

The paper presents results of laboratory tests, purpose was to recognize distributions of flow velocity in the local scour. Investigations were conducted on model of weir with overflow under closure, bottom of water basins, horizontal bed protection in downstream and scouring area. As eroded material on model sorted sand was used with d50 = 1.1 mm. Results analysis was conducted in order to establish changing of velocity profi les during increase of scour depth. Distributions of velocity have different shape. Profiles of velocity depend on the location of measuring place in the local scour. Below the bed protection the roller with horizontal axis is formed. It has a decisive infl uence on the velocity distribution in the local scour