Experimental study of discharge Coefficient of Piano Key Side Weir in 45-Degree Sector of a curved channel

Document Type : Research Paper

Authors

• Babak Ghobadi ¹
• Mojtaba Saneie ²

¹ M.Sc. Student, Water and Hydraulic Structures, Civil Engineering Department, University of Science & Culture, Tehran, Iran.

² Associate Professor, Soil Conservation and Watershed Management Research Institute, Agricultural Research Education and Extension Organization (AREEO), Tehran, Iran.

Abstract

A new type of Long-crested weirs is Piano Key weir that allows the reservoir to run at a higher level. The use of a Piano Key weir as side weir allows for more drainage, due to the geometric shape of the channel and the impact of centrifugal force on the flow, in a channel having longitudinal curvature. This research, examine the Changing of flow pattern and discharge coefficient of a Type-B Piano Key weir in 45-degree sector of a channel having longitudinal curvature by Experimental investigation. Experiments were carried out in a certain range of changes in geometric and hydraulic parameters, and the effect of each of the dimensionless parameters on the flow was determined. It is worth noting that all experiments with rectangular sharp-crested weirs have been compared. The result of this study is the high discharge coefficient of Piano Key side weir relative to the rectangular sharp-crested weir. Also, the L/b and Froude number parameters have a significant impact on the performance of the Piano Key side weir in 45-degree sector of a channel having longitudinal curvature. From other results of this research is the flow pattern that from beginning to end of the Piano Key side weir that height of the surface of the flow dropping dramatically at beginning of the weir, and eventually reaching its initial level, which is associated with lower variations in the higher heads. These deformations have been much lower when used with rectangular sharp-crested weirs.

Keywords

• piano key weir
• curved channel
• discharge coefficient
• side weir
• experimental investigation

20.1001.1.20086377.1399.13.46.3.8

---

References

1)        Gholami, A., Akbar Akhtari, A., Minatour, Y., Bonakdari, H., & Javadi, A. A. 2014. Experimental and numerical study on velocity fields and water surface profile in a strongly-curved 90 open channelbend. Engineering Applications of omputational Fluid Mechanics, 8(3), 447-461.

 

2)        Shamshirband, S., Bonakdari, H., Zaji, A. H., Petkovic, D., & Motamedi, S. 2016. Improved side weir discharge coefficient modeling by adaptive neuro-fuzzy methodology. KSCE Journal of Civil Engineering, 20(7), 2999-3005.

3)        Emiroglu, M. E., Kaya, N., & Agaccioglu, H. 2009. Discharge capacity of labyrinth side weir located on a straight channel. Journal of irrigation and drainage engineering, 136(1), 37-46.

4)        Pralong, J., Vermeulen, J., Blancher, B., Laugier, F., Erpicum, S., Machiels, O., Pirotton, M., Boillat, J. L., Leite Ribeiro, M. and A. J. Schleiss. 2011. A naming convention for the Piano Key weirs geometrical parameters. Proceeding of international conference on Labyrinth and Piano Key weirs, Liège B, 271-278. CRC Press.

5)        A.R. Afzalian and J. Ahadiyan. 2014. Piano key weir with sloped parapet wall, Journal of Irrigation Science & Engineering (in Persian)

6)        Lempérière, F., and Ouamane, A., 2003. The Piano Keys weir: a new cost-effective solution for spillways, Int.J. Hydropower and Dams, Vol. 10, No.5, PP.144-149.

7)        M. Karimi, J. Attari, M. Saneie, M.R. Jalili Ghazizadeh. 2017. Experimental study of discharge coefficient of a Piano Key Side Weir, in: Proc. 3nd Int. Work.  Labyrinth Piano Key Weirs, Vietnam, pp. 109–116.

8)        M. Karimi, J. Attari, M. Saneie, M.R. Jalili Ghazizadeh. 2018. Side Weir Flow Characteristics: Comparison of Piano Key, Labyrinth, and Linear Types, J. Hydraul. Eng. 144, 4018075. doi: 10.1061/(ASCE)HY.1943-7900.0001539.

9)        Kabiri-Samani, A.; Javaheri, A. 2012. Discharge coefficients for free and submerged flow over Piano Key weirs. Journal of Hydraulic Research, 50(1), 114-120.

10)     A. Saghari, K. Hosseini, M. Sanei. 2019. Experimental study of trapezoidal piano key side weirs in a curved channel, Flow Measurement and Instrumentation,https://doi.org/10.1016/j.flowmeasinst.2019.101640.