Shahid Chamran University of AhvazIrrigation Sciences and Engineering2588-595244420211222Two Cycle Circular Piano Key Weir Blocking Probability Assessment along Indivual ExperimentTwo Cycle Circular Piano Key Weir Blocking Probability Assessment along Indivual Experiment45571738110.22055/jise.2017.22015.1575FASaeidHabibiMaster Geaduate, Civil Engineering Department, Jundi-Shapur University of Technology, Dezful, Iran.BabakLashkararaAssociate Proffessor, Civil Engineering Department, Jundi-Shapur University of Technology, Dezful, Iran.Journal Article20190508This study uses the blocking of a two-cycle circular piano key weir (C.P.K) that benefits from a considerable vortex breaking capability compared to other kinds. To do so, the impact of floating objects on the blocking amount of this weir is investigated using 13 pieces of wood with slenderness coefficients (<em>L<sub>d</sub>/D<sub>d</sub></em>) of 15, 20, and 25. Three slopes of 1:0.5, 1:1, and 1:1.5 (vertical: horizontal) were chosen to study the impact of the bottom slope of the input and output keys on the blocking probability. To reach the mentioned slopes, the shape of the weir was designed and built with three <em>P/D</em> relative heights of 0.5, 1, and 1.5. The experiments showed that the weir had more blocking probability with a relative height of 1.5 than the other models with fewer key slopes. In addition, individual experiments revealed that the diameter of floating objects was more influential on blocking probability than the length of the objects and the amount of upstream watery load. It can generally be concluded that increasing the diameter and length of the floating objects are directly and indirectly correlated with the blocking amount and the amount of watery load on the weir crown, respectively. Comparing the obtained results with the bell-mouth spillway reveals that the C.P.K weir benefits from more sediment trapping capability.This study uses the blocking of a two-cycle circular piano key weir (C.P.K) that benefits from a considerable vortex breaking capability compared to other kinds. To do so, the impact of floating objects on the blocking amount of this weir is investigated using 13 pieces of wood with slenderness coefficients (<em>L<sub>d</sub>/D<sub>d</sub></em>) of 15, 20, and 25. Three slopes of 1:0.5, 1:1, and 1:1.5 (vertical: horizontal) were chosen to study the impact of the bottom slope of the input and output keys on the blocking probability. To reach the mentioned slopes, the shape of the weir was designed and built with three <em>P/D</em> relative heights of 0.5, 1, and 1.5. The experiments showed that the weir had more blocking probability with a relative height of 1.5 than the other models with fewer key slopes. In addition, individual experiments revealed that the diameter of floating objects was more influential on blocking probability than the length of the objects and the amount of upstream watery load. It can generally be concluded that increasing the diameter and length of the floating objects are directly and indirectly correlated with the blocking amount and the amount of watery load on the weir crown, respectively. Comparing the obtained results with the bell-mouth spillway reveals that the C.P.K weir benefits from more sediment trapping capability.https://jise.scu.ac.ir/article_17381_2314003f3729531ae7e62e5a2d005586.pdf