An experimental and numerical study on the flow field and scour downstream of rectangular piano key weirs with crest indentations

• Published in: Innovative infrastructure solutions : the official journal of the Soil-Structure Interaction Group in Egypt (SSIGE) 2023-05, Vol.8 (5), Article 140
• Main Authors: Abdi Chooplou, Chonoor, Ghodsian, Masoud, Abediakbar, Davoud, Ghafouri, Aram
• Format: Article
• Language: English
• Subjects: Earth and Environmental Science; Earth Sciences; Environmental Science and Engineering; Foundations; Geoengineering; Geotechnical Engineering & Applied Earth Sciences; Hydraulics; Practice-oriented Paper
• ISSN: 2364-4176; 2364-4184
• DOI: 10.1007/s41062-023-01108-7

In this research, the flow and scour patterns downstream of type-A rectangular piano key weirs (PKWs) were studied experimentally and numerically. Variations of the bed topography downstream of the PKW with different lateral crest shapes, i.e., a standard crest and a crest with an indentation in various geometries, including triangular, half-circular, sinusoidal, rectangular, and fort crests, were investigated using a Flow-3D numerical model. The results showed that the Flow-3D model simulated the flow and scour with acceptable accuracies. Indentations of the lateral crests substantially influenced the geometrical characteristics of the scour hole, including weir toe scour depth, maximum scour depth, scour hole area, and scour hole volume. The lowest value of maximum scour depth occurred with triangular indentations of the crest. In this case, decreases of 10.5 and 17% in the longitudinal and vertical components of flow velocity at the weir crest level and below it reduced the local scour by 38%. The higher flow energy in the weir with rectangular indentations caused the location of maximum scour depth to occur at a farther distance from the weir toe. The lowest upstream and downstream slopes of the scour hole were observed in the models with rectangular and fort crest indentations of lateral crests.