The Effect of Upstream Overhang on the Debris Blocking and Discharge Capacity of Piano Key Weirs

Document Type : پژوهشی

Authors

• Mohammad Poshteh-Shirani
• Majid Rahimpour
• Mohammad Mehdi Ahmadi

Shahid Bahonar University of Kerman

10.22067/civil.v30i2.51432

Abstract

Piano Key Weir (PKW) is a flow control structure and it is a developed version of non-linear weirs that has a high discharge capacity, so that, for a specified discharge rate, the flow head above the weir is small, which may increase the likelihood of woody debris collection. In this study, the discharge capacity were investigated through 5 different geometry of the weir with the ratio exit to entrance lengh overhang with the values Bo/Bi=0, 0.5, 1, 1.25 and 1.5 and also the probability of woody debris collection using five models wood ad the location of the critical zone for obstructing the debris in the said weir was studied. The results indicate that increasing the length of the spillway crest increased discharge capacity, so that PKW1.5 than to PKW0 has increase discharge capacity to 26 percent. Also at a constant discharge PKW1.25 than other models in this study is less sensitive to ocllecion. And likelihood of trunk woody debris collection at this model relative to the models with ratios of Bo/Bi=0, 0.5, 1 and 1.5 has 7/18, 2/39, 9/38 and 8/7 percent less respectively. Also in all models most obstruction was occurred in the entrance region of exit keys.

Keywords

• Piano Key Weir
• Discharge Capacity
• Overhang, Sample of Wood
• likelihood of Collection

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References

1. Khode, B.V., and Tembhurkar. A.R.,"Evaluation and Analysis of Crest Coefficient for Labyrinth Weir", World Applied Sciences Journal, Vol. 11, PP. 835-839,) 2010).

2. Lemperière, F., Ouamane, A., "The Piano Keys Weir: A New Cost Effective Solution for Spillways, Hydropower and Dams", Official Journal of the International Hydropower Association, Vol. 10 PP.144–149, )2003.(

3. Blanc, P., Lemperière, F., "Labyrinth Spillways Have a Promising Future", Journal of Hydropower Dams, Vol.8, PP. 129-131,)2001.(

4. Riberio, M.L., Pfister, M., Schleiss,A.J., and Boillat,J.L., "Hydraulic Design of A-type Piano Key Weirs", Journal of Hydraulic Research, Vol. 50, PP. 400–408, ( 2012).

5. Lemperière, F., Vigny, J.P., Ouamane, A., "General Comments on Labyrinth and Piano Key Weirs: The past and present", proceedings of the International Conference Labyrinth and Piano Key Weirs, Liège B, 17–24 CRC Press, Boca Raton, FL,(2011).

6. Anderson, R.M., and Tullis, B.P., "Piano Key Weir Hydraulics and Labyrinth Weir Comparison", Journal of Irrigation and Drainage Engineering, Vol. 139, PP. 246-253,) 2013.(

7. Kabiri-Samani, A., and Javaheri, A., "Discharge Coefficients for Free and Submerged Flow over Piano Key weirs", Journal of Hydraulic Research, Vol. 50, PP. 114–120, (2012).

8. Pralong, J., Vermeulen, J., Blancher, B., and Laugier, F.,"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, (2011).

9. Machiels, O., Erpicum, S., Archambeau, P., Dewals, B.J., Pirotton, M., "Piano Key Weir Preliminary Design Method: Application to a New Dam Project", proceedings of the International Conference Labyrinth and Piano Key Weirs, Liège B, CRC Press, Boca Raton, FL, PP. 199–206, (2011).

10. Barcouda, M., Cazaillet, O., Cochet, P., Jones, B.A., Lacroix, S., "Cost-effective Increase in Storage and Safety of Most Dams Using Fuse Gates or P. K. Weirs", proceedings of the International Symposium on Dams in the Societies of the 22st Century, International Commission on Large Dams (ICOLD), Barcelona, Spain, PP. 463–470, (2006).

11. Ouamane, A., and Lemperière, F., "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. 463–470,(2006).

12. Ribeiro, M.L., Pfister, M., Schleiss, A.J., "Overview of Piano Key weir prototypes and scientific model investigations", Proceedings of the 2nd International Workshop on Labyrinth and Piano Key Weirs, p, 273-281, CRC Press, Boca Raton, (2013).

13. Pfister, M., Capobianco, D., Tullis, B., and Schleiss, A.J., "Debris-Blocking Sensitivity of Piano Key Weirs under Reservoir-Type Approach Flow", Journal of Hydraulic Engineering, Vol. 139, PP. 1134-1141, (2013).

14. Pagliara, S., and Carnacina, I., "Temporal Scour Evolution at Bridge Piers: Effect of Wood Debris Roughness and Porosity", Journal of Hydraulic Research, Vol.48, PP. 3–13, (2010).

15. Laugier, F., "Design and Construction of the First Piano Key Weir Spillway at Goulours Dam", International Journal of Hydropower Dams, Vol.13, PP. 94–100, )2007.(

16. Ribeiro, M.L., Bieri, M., Boillat, J.L., Schleiss, A.J., Singhal,G., and Sharma, N.,"Discharge Capacity of Piano Key Weirs", Journal Hydraulic Engineering, Vol.138, PP.199–203, (2012).

17. منصوری، کوثر، و احدیان، جواد، «انسداد سرریزهای کلید پیانویی در جریان‌های آواری با سیستم آزمایش‌های انفرادی»، علوم و مهندسی آبیاری (مجلۀ علمی- پژوهشی(، ج. 39، ش. 3، (پاییز 95).

18. Anderson, R.M., and Tullis, B.P., "Comparison of Piano Key and Rectangular Labyrinth Weir Hydraulics", Journal of Hydraulic Engineering, Vol. 138, PP.358–361, )2012(.

19. Tullis, J. P., Amanian, N., and Waldron, D., "Design of Labyrinth Spillways", Journal of Hydraul Engineering, Vol.121, PP. 247–255, (1995).

20. Anderson, R.M., Tullis, B., "Influence of Piano Key Weir geometry on discharge", proceedings of the International Conference Labyrinth and Piano Key Weirs, Liège B, CRC Press, Boca Raton, FL, PP.75-80, (2011).

21. Anderson, R.M., "Piano Key Weir Head Discharge Relationships", All Graduate Theses and Dissertations, Utah State University, (2011).