عنوان مقاله [English]
Piano key weirs (PKWs), a new type of weirs with a very high discharge capacity, can be used as high performance economic structures. This type of weirs is a good alternative to linear weirs, because they increase the discharge per unit width at the span of non-regulated weirs for the same water load and weir width. In this study, the discharge coefficient of piano key weirs was compared with that of a rectangular labyrinth weir. The results showed 38% increase in the discharge coefficient of the piano key weirs as compared to that of the rectangular labyrinth weir. The difference between the discharge coefficients of the weirs was reduced by increasing hydraulic load when reaching the submergence discharge. The difference was reduced about 24% at high discharges. In addition, the tailwater level was gradually increased from the weir crown level.
Keywords : discharge coefficients , labyrinth weir, PKW, weir with a rectangular-shaped plan.
Anderson, R. M. and Tullis, B. P. 2011. Influence of Piano KeyWeir geometry on discharge. Labyrinth and Piano Key Weirs, PKW 2011 – Erpicum et al. (Eds.) Taylor & Francis Group, London, ISBN 978-0-415-68282-4-: 75-80.
Anderson, R. M. and Tullis, B. 2012. Comparison of piano key and rectangular labyrinth weir hydraulics. J. Hydraul. Eng. 138(4): 358-361.
Cicero, G. M., Laugier, F. and Vermeulen, J. 2017. Synthesis of Piano Key Weir experimental studies at LNHE, Labyrinth and Piano Key Weirs III – PKW 2017 – Erpicum et al. (Eds) © 2017 Taylor & Francis Group, London, ISBN 978-1-138-05010-5.
Crookston, B. M. and Tullis, B. P. 2012a. Discharge efficiency of reservoir application specific labyrinth weirs. J. Irrig. Drain. Eng. ASCE. 138(6): 773-776.
Crookston, B. M. and Tullis, B. P. 2012b. Arced labyrinth weirs. J. Hydraul. Eng. ASCE. 138(6): 555-562.
Crookston, B. M. and Tullis, B. P. 2012c. Labyrinth weirs: nappe interference and local submergence. J. Irrig. Drain. Eng. ASCE. 138(8): 757-765.
Falvey, H. T. 2003. Hydraulic Design of Labyrinth Weirs. ASCE Press, USA.
Gebhardt, M., Merkel, J., Belzner, F. and Thorenz, C. 2017. A comparison of side weirs and labyrinth weirs at Ilmenau river.Labyrinth and Piano Key Weirs III – PKW 2017 – Erpicum et al. (Eds) © 2017 Taylor & Francis Group, London, ISBN 978-1-138-05010-5.
Hay, N. and Taylor, G. 1970. Performance and design of labyrinth weirs. J. Hydraul. Div. ASCE.
Heidarpoor, M., Mousavi, F. and Roshani-Zarmehri, A. R. 2006. Labyrinth weirs with rectangular and
U-shape plan-forms. J. Agric. Sci. Nat. Resour. 10(3A): 1-11. (in Persian)
Javaheri, A. and Kabiri-Samani, A. 2011. Determination of PKW discharge coefficient in free flow condition. The first International Conference and the Third National Conference on Dam and Hydroelectric Plants. Feb. 8-9. Tehran, Iran. (in Persian)
Karimi, M., Attari, J., Saneie, M. and Jalili, M. 2017. Experimental study of discharge coefficient of a Piano Key SideWeir,Labyrinth and Piano Key Weirs III – PKW 2017 – Erpicum et al. (Eds) © 2017 Taylor & Francis Group, London, ISBN 978-1-138-05010-5.
Leite-Ribeiro, M., Pfister, M., Boillat, J. L., Schleiss, A. J. and Laugier, F. 2012. Piano key weirs as efficient spillway structure. 24th ICOLD Congress on Large Dams, Kyoto, Japan.
Ouamane, A. and Lempérière, F. 2006. Design of a new economic shape of weir. Proceeding International Symposium on Dams in the Societies of the 21st Century. June 18. Barcelona, Spain.
Sajadi, S. M., Ahadian, J. and Ghanavati, M. 2017. Effect of baffled outlet keys at piano key weir on dissipating energy. Irrig. Drain. Strut. Eng. Res.18(69): 77-92. (in Persian)
Tullis, B., Young, J. and Chandler, M. 2007. Head-discharge relationships for submerged labyrinth weirs. J. Hydraul. Eng. 133(3): 248-254.
Tullis, P., Amanian, N. and Waldron, D. 1995. Design of labyrinth weir spillways. J. Hydraul. Eng. ASCE. 121(3): 247-255.
Villemonte, J. R. 1947. Submerged weir discharge studies. Eng. News Record. 139(26): 54-56.