Study Effect of Fluctuations of Pressure Factors of Stepped Short-throat Shaft Spillways on Hydraulic Coefficient

Document Type : Original Article

Authors

Department of Civil Engineering, Engineering Faculty, Islamic Azad University, Sepidan Branch, Sepidan, Iran.

Abstract

Stepped spillways discharge more flow through themselves than smooth spillways theoretically. Therefore, understanding the flow behavior of these spillways can lead to better and more efficient use. In addition, the use of vortex breaker. can have a large impact on flow through the shaft spillway. For more efficient use, the risk of flow pressure dropping below the fluid vapor pressure, known as cavitation, should be prevented as much as possible. As for the spillways with stepped conduits (three steps), the pressure changes were found to be very tangible using a sextuple arrangement of vortex breakers for intermediate discharge rates; in some of the states, the pressure on the spillway's body is found to be intensely decreased. Based on the research, the best performance belongs to the morning glory-type spillway with 12 steps and three vortex breakers on the crest, as these accessories play an essential role in controlling the discharge rate and preventing cavitation. It is worth mentioning that the vortex breaker's dimensions based on the ratio of the vortex breaker's thickness (T) to the spillway's diameter (d) would not have an effect of more than 12.5% on the separation of the flow lines. In this study, an attempt was made to investigate the effect of different behaviors of the stepped chamber and different vortex shapes on the spillway flow. Based on the present experimental investigation, the following conclusions may be concluded:

Maximum risk of flow rate is magnitude at 1/3 down side of shaft.

Keywords

References

Chanson, H., 2001. Hydraulics of Stepped Chutes and Spillways. A.A. Balkema Publishers, Tokyo, Japan.
Jean Pierre, F., Jean Pierre, M., 2004. Fundamentals of Cavitations. Kluwer Academic Publishers, New York, Boston, Dordrecht, London, Moscow.
Musavi-Jahromi, S., Hajipour, G., Eghdam, M., 2016. Discharge Coefficient in the Morning Glory Spillways due to Longitudinal Angles of Vortex Breakers. Bulletin of Environment. Pharmacology and Life Sciences, 5(5): 34-41.
Razavi, A.R., Ahmadi, H., 2017. Numerical Modelling of Flow in Morning Glory Spillways Using FLOW-3D. Civil Engineering Journal, 6(10): 956-964.
Salmasi, F., 2003. Hydraulic Transition Flow Regime from Stepped Spillways. Scientific Research Journal, 26(2): 1-13. (In Persian).
Sayadzadeh, F., Musavi-Jahromi, S., Sedghi, H., Khosrojerdi, A., 2020. Pyramidal vortex breakers influences on the flow discharge of morning glory spillway. Ain Shams Engineering Journal, 11(2): 455-463.
Shuguang, L., Yonglai, Z., Zhengji, Z., Congxian, L., 2002. Sediment load of Asian rivers flowing into the Oceans and their regional variation. Mirage, 4(1): 61-70.
Shukla, S., Jain, S.K., Kansal, M., Chandniha, S.K., 2017. Assessment of sedimentation in Pong and Bhakra reservoirs in Himachal Pradesh, India, using geospatial technique. Remote Sensing Applications: Society and Environment, 8: 148-156.
Sumi, T., Kantoush, S.A., 2010. Integrated management of reservoir sediment routing by flushing, replenishing, and bypassing sediments in Japanese river basins, Proceedings of the 8th International Symposium on Ecohydraulics, Seoul, Korea, pp. 831-838.
Yoon, Y., 1992. The state and the perspective of the direct sediment removal methods from reservoirs. International Journal of Sediment Research, 7(20): 99-115.  
Journal of Hydraulic and Water Engineering
Volume 1, Issue 1
July 2023
Pages 137-150

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