Discharge Estimation over Piano Key Weirs: A Review of Recent Developments

The piano key (PK) weir has advanced over the labyrinth to increase discharge capacity. Piano weirs exhibit nonlinear flow behavior and are easy place on existing spillway or newly constructed dam with less base area. Various investigators given equations calculate coefficient for free submerged conditions. study focuses reviewing impacts of PK geometry coefficient, including length height, upstream downstream widths, apex overhangs. In this study, all possible aspects were briefly reviewed. From sensitivity analysis, it is observed that more sensitive L/W dimensionless ratio followed by B/P ratio. L total crest, W width weir, B P height weir. This review paper intended serve as an accessible resource hydraulic structures researchers engineering professionals alike interested in hydraulics weirs.