Effects of Nose and Piano Keys Weir Parapet Wall on Floating Woody Debris

Document Type : Research Paper

Authors

Abstract

A hydraulic structure is a device designed to retain, regulate, or control the flow of water. The most common type of hydraulic structures are weirs. Weirs are overflow structures that stretch across an open channel of water, and are meant to alter the channel’s flow characteristics making it easier to measure the volumetric rate of water flow. The Piano Key Weir (PKW), a type of Labyrinth weir is a hydraulically attractive option to linear overflow weirs, increasing the unit discharge for similar heads and spillway widths (Anderson, 2011). Together with its high discharge capacity for low heads, this geometry makes these weirs interesting in dam (Laugier, 2007). Discharge passing capacity of piano key weir is higher than that of labyrinth weir for same condition (Anderson and Tullis, 2013). In PKW type A, the upstream and downstream overhangs are existence, and if PK weir without downstream, upstream or both overhangs, it is B, C and D respectively (Lemperier and Quamane, 2003).
Anytime an engineered structure like a weir structure is placed in a river environment, the possibility exists that it will encounter debris. The impact of this debris on a structure is an important aspect of the design (Pagliara and Carnacina, 2010).  Historically, debris accumulation on bridge piers and hydroelectric dams has been among the chief concerns associated with river debris. As the amount of debris builds on an object, the force it exerts on the object can result in catastrophic failure and it reduces the flow, resulting in the buildup of a backwater and greatly reducing the efficiency of energy conversion.
Due to the geometric properties and low flow head of PK weir, floating debris obstruction can occur in this structure. As shown in Fig.1, fundamental parameters on a PKW are including: height of PK-Weir P, total width of PK-Weir W, inlet key width Wi, outlet key width Wo, length of PKW B, PK weir footprint length Bb, upstream (outlet key) overhang lengths Bo, downstream (inlet key) overhang lengths Bi, weir wall thickness Ts, and flow discharge Q. In this research the effect of floating debris on PK weir obstruction investigated experimentally. The geometry of PKW and debris parameter was studied.

Keywords

Main Subjects

References

1-    افضلیان، ع. ر. و احدیان، ج. 1394. سرریز کلیدپیانویی با پارپت وال های زاویه دار، مجله علوم و مهندسی آبیاری، دانشگاه شهید چمران اهواز، 38(2): 91-102.
 
2-    یارمحمدی، ب. و احدیان، ج. 1395. بررسی آزمایشگاهی هیدرولیک جریان سرریز کلیدپیانویی در ترکیب های مختلف دیواره سپری، مجله علوم و مهندسی آبیاری، دانشگاه شهید چمران اهواز، 39(4): 47-58.
 
3-    Anderson, R.M. 2011. Piano Key weir head discharge relationships. M.Sc. Thesis, Utah StateUniversity. Logan, UT.
 
4-    Anderson, R.M. and B. P. Tullis. 2013. Piano Key weir hydraulics and Labyrinth weir comparison. Journal of Irrigation and Drainage Engineering, 139(11): 246-253.
 
5-    Dabling, M.R. and B.P. Tullis. 2012. Piano Key weir submergence in channel applications. Journal of Hydraulic Engineering, 138(7): 661–666.
 
6-    Kabiri-Samani, A. and A. Javaheri. 2012. Discharge coefficients for free and submerged flow over Piano Key weirs. Journal of Hydraulic Research, 50(1):114–120.
 
7-    Laugier, F. 2007. Design and construction of the first Piano Key weir spillway at Goulours dam. International Journal of Hydropower Dams, 13(5): 94–100.
 
8-    Lempérière, F. and A. Ouamane. 2003. The Piano Keys weir: A new cost effective solution for spillways. Hydropower and Dams. Official Journal of the Intervational Hydropower Association, 10(5):144–149.
 
9-    Ouamane, A. and F. Lempérière .2006. Design of a new economic shape of weir. proceedings of the International Symposium on Dams in the Societies of the 21st Century, International Commission on Large Dams (ICOLD), Taylor and Francis. London, UK pp. 463–470.
 
10- Pagliara, S. and I. Carnacina. 2010. Temporal scour evolution at bridge piers: effect of wood debris roughness and porosity. Journal of Hydraulic Research, 48(1): 3–13.
 
11- Pfister, M., Capobianco. D., Blake Tullis, B. and A.J. Schleiss. 2013. Debris-blocking sensitivity of Piano Key weirs under reservoir-type approach flow. Journal of Hydraulic Engineering, 139(11): 1134-1141.
 
12- Pralong, J., Vermeulen, J. Blancher, B. and F. Laugier. 2011. A naming convention for the Piano Key weirs geometrical parameters. Proceedings of the International Conference Labyrinth and Piano Key Weirs, Liège B, CRC Press, Boca Raton, FL, pp.271–278.
 
13- Ribeiro, M. L., Bieri, M., Boillat, J. L., Schleiss, A. J., Delorme, F. and F. Laugier. 2009. Hydraulic capacity improvement of existing spillways. Design of Piano Key weirs. Proceedings 23rd Congress of International Commission on Large Dams (ICOLD), International Committee on Large Dams (ICOLD), Paris.
 
14- Ribeiro, M. L., Bieri, M., Boillat, J. L., Schleiss, A. J., Singhal, G., and N. Sharma. 2012a. Discharge capacity of Piano Key weirs. Journal of Hydraulic Engineering, 138(2): 199–203.
 
15- Riberio, M. L.,  Pfister, M., Schleiss, A. J., and J. L. Boillat. 2012b. Hydraulic design of A-type Piano Key weirs. Journal of Hydraulic Research, 50(4): 400–408.
Irrigation Sciences and Engineering
Volume 40, Issue 3
December 2017
Pages 99-107

Files

History

  • Receive Date: 25 October 2015
  • Revise Date: 25 April 2016
  • Accept Date: 04 July 2016
  • Publish Date: 22 November 2017

Share

How to cite

Statistics