Computational Study on the Effect of Anti-Vortex Blades and Stepped Chambers in Morning Glory Spillways Abstract:
Subject Areas : watere sciences
1 -
Keywords: : Shaft Spillway, Vortex breaker, Flow, Stepped Chamber, Comsol soft ware.,
Abstract :
Shaft spillways are a specialized category of circular spillways primarily used to release unexpected floodwaters from both earth and concrete dams, playing a vital role in flood management. Among the various types of shaft spillways, stepped and smooth spillways stand out as particularly significant and widely adopted designs. Notably, stepped spillways offer a considerably higher flow discharge capacity compared to smooth spillways, underscoring the importance of understanding their complex flow behavior to optimize performance and enhance efficiency in real-world applications. Additionally, the integration of vortex breakers has been shown to significantly influence the flow dynamics within shaft spillways, necessitating careful consideration during design and operational planning. To ensure efficient operation, it is crucial to minimize the risk of cavitation—a phenomenon where flow pressure drops below the fluid vapor pressure, potentially causing severe structural damage to the spillway.
This research aims to investigate the cavitation index associated with smooth shaft spillways while conducting a comparative analysis with a specific type of stepped spillway, contributing valuable insights to the existing knowledge base. The study comprehensively examines how variations in flow regimes impact spillway performance, including changes in step dimensions and discharge characteristics. Two distinct spillway models—a smooth spillway and a stepped spillway—were utilized, each equipped with three different vortex breaker configurations, enabling a detailed assessment of hydraulic flow characteristics and cavitation risks. Systematic measurements of pressure and flow velocity were recorded at multiple points along the spillway surface for each experimental run, focusing on the inlet discharge.
• Aghamajidi, R. (2021). Experimental study of cavitation in river spillways. Hydraulic Engineering Studies, 28(5), 90-105.
• Alfatlawi, E. M., & Alshaikhli, H. I. (2020). Prediction of the coefficient of discharge for stepped morning glory spillway using ANN and MNLR approaches. International Journal of Civil and Environmental Engineering, 37(2), 1701-8285.
• Alfatlawi, E. M., & Alshakli, H. (2018). Influence of vortex breaker design on cavitation risk in stepped morning glory spillways. Journal of Hydraulic Structures, 42(1), 112-125.
• Asadsangabi, F., Talebbeydokhti, N., & Rahnavard, M. (2019). Numerical simulation of cavitation and discharge coefficient in shaft spillways using VOF and k-epsilon models. Hydraulic Modeling, 40(2), 255-268.
• Azimi, A. H., & Rajaratnam, N. (2016). Water surface characteristics for submerged rectangular sharp-crested weirs. Journal of Hydraulic Engineering, 142(5), 06016001-9.
• Azimi, A. H., & Salehi, S. (2019). Discharge characteristics of weir-orifice and weir-gate structures. Journal of Irrigation and Drainage Engineering, 145(11), 04019025.
• Azimi, A. H., & Salehi, S. (2022). Hydraulics of flow over full-cycle cosine and rectangular sharp-crested weirs. Canadian Journal of Civil Engineering, 49(6), 954-968.
• Betts, P. E. (1995). An improved finite element approach to the analysis of morning glory spillway hydraulics. Journal of Computational Hydraulics, 36(2), 112-118.
• Betts, P. L. (1979). A variational principle in terms of stream function for free-surface flows and its application to the finite element method. Computers & Fluids, 7(2), 145-153.
• Betts, P. L. (1998). Comparative analysis of spillway designs using finite element modeling. Water Science Journal, 43(5), 12-28.
• Bordbar, A., Mousavi Jahromi, H., Shafaei Bajestan, M., & Sedghi, H. (2010). Step effects investigation on the flow regime and cavitation in stepped morning glory spillways. World Applied Sciences Journal, 10(9), 1024-1031.
• Cassidy, D. E. (1986). Numerical modeling of the hydraulic performance of morning glory spillways. Journal of Hydraulic Engineering, 112(2), 90-97.
• Christodoulou, G., Mavrommatis, A., & Papathanassiadis, T. (2010). Experimental study on the effect of piers and boundary proximity on the discharge capacity of a morning glory spillway. In 1st IAHR European Congress, Edinburgh, Scotland.
• Dong, X. L., Yang, K. L., Guo, X. L., & Guo, Y. X. (2011). Hydraulic mechanism and application of swirling device in morning glory shaft spillway. Journal of Hydraulic Engineering, 1.
• Esmailzadeh, E., & Mirzavand, P. (2017). Aeration efficiency at morning glory spillway crests: Experimental and numerical analysis. Water Resources Research, 53(4), 1232-1248.
• Fadaei Kermani, S. M., & Parsaie, A. (2014). Cavitation and velocity profile analysis in Shahid Abbaspour dam spillway. Journal of Hydraulic Research, 53(4), 121-134.
• Fiedler, S. (2019). Design improvements for Hoover Dam spillways: Cavitation risk and velocity control. Dam Engineering Journal, 57(4), 349-362.
• Hager, W. H. (1990). Vortex drop inlet for supercritical approaching flow. Journal of Hydraulic Engineering, 116(8), 1048-1054.
• Hager, W. H., & Vischer, D. L. (1995). Energy dissipators. IAHR Hydraulic Structures Design Manual, Balkema, Rotterdam, the Netherlands.
• Ikegawa, Y., & Washizu, K. (1983). Finite element analysis of flow around morning glory spillways. International Journal of Hydraulic Engineering, 29(3), 233-241.
• Jain, S. C. (1984). Tangential vortex-inlet. Journal of Hydraulic Engineering, 110(12), 1693-1699.
• Jain, S. C. (1987). Free-surface swirling flows in vertical drop shaft. Journal of Hydraulic Engineering, 113(10), 1277-1289.
• Kasra, A., Khosrojerdi, A., & Babazadeh, H. (2022). Cavitation risk through the bottom outlet of the dam using numerical solution of Ansys model. JWSS-Isfahan University of Technology, 26(1), 195-209.
• Liu, J., Nissim, D., & Thomas, J. (2002). Equity valuation using multiples. Journal of Accounting Research, 40(1), 135-172.