Comparison of Discharge Coefficient Between Arced Piano Key Weir and Non-Arc Piano Key Weirs

In this paper, discharge coefficient of arced piano key weir compared against two models of normal or fashionable piano key weirs with no arc in their plan. The arced piano key weirs are less investigated. Piano key weirs are pretty new sort of labyrinth weirs with fewer footprint needs. They are used in limited width and mountainous situation and have a high potential for rehabilitation and almost easy to build them in the last decade. They are more applied, especially in rehabilitation. Arc in front of inlet key and at the end of outlet key proposed and evaluated experimentally only in discharge aspect. For the purpose of the simulation of what really happens and calculation of discharge coefficient, three models are made and measured. The results of volumetric discharge coefficient show that arced piano key weir in four different level of upstream flow are 12.07 and 11.33 and 14.77 and 11.01 percent higher than best Non-Arc Piano key weirs.