Analytical integration investigation of hydraulic of piano key weirs (PKW) with Continues and discontinues parapet walls

Document Type : Original Article


1 Msc Student of Hydraulic Structures, Faculty of Water Sciences and Engineering, Shahid Chamran University, Ahwaz, Iran

2 Assistant Professor, Water engineering department, Faculty of Water Science Engineering, shahid chamran university


Nowadays piano key weirs (PKW) are widely used in many projects, because, in comparison to linier weirs, they have high discharge capacity and more storage volume of dam reservoir. The piano key weirs performance reduce in high discharges, so this research investigate the various combinations of interrupted non-sloped and sloped parapet walls on the piano key weirs performance. It is used an experimental flume to do research. By using analytical integration method, the results show that they improve the weir performance about 35 percent, when the 4.5-centimeter-hight non-sloped parapet walls were on the weir’s side crest, while setting non-sloped parapet walls on the whole of the weir crest increase it about 14.8 percent. In addition the sloped parapet walls improve the weir performance. According to this method, the results show that the discontinued parapet walls improve the weir performance. Finally, by SPSS software, two equations were developed for the piano key weirs discharge coefficient with sloped and non-sloped parapet walls. For non-sloped models, these equations have respectively regression coefficients, measuring error index, RMSE, and MAE about 0.783, 0.048 and 0.03, but for sloped models, they are about 0.941, 0.03, and 0.025.


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