The Effect of Suspended Load on the Lower Discharge of Large Dams using Flow-3D Numerical Model

Document Type : Original Article

Authors

1 MSc Student, Department of Water Engineering, Faculty of Agriculture, Takestan Branch, Islamic Azad University, Takestan, Iran Islamic Azad University, Takestan Branch, Takestan, Iran.

2 Assistant Professor, Department of Water Engineering, Faculty of Agriculture, Takestan Branch, Islamic Azad University, Takestan, Iran.

3 BSc Graduated, School of Engineering, Damghan University, Damghan, Iran.

10.22044/jhwe.2025.15424.1046

Abstract

Bottom outlets in dams are critical structures for regulating flow and releasing sediment, particularly during floods and emergency situations. These systems play a vital role in ensuring dam safety and effective water management. While previous studies have primarily focused on flow simulation without considering suspended sediments, this omission overlooks a significant factor influencing outlet performance under flood conditions. Suspended sediments increase the density of the flow, which can substantially alter the hydraulic characteristics of the outlet system. This study investigates the effect of suspended sediment concentration on the hydraulic efficiency of bottom outlets, using Flow-3D software to model the flow dynamics within the bottom outlet of Siazakh Dam. Siazakh Dam is located 7 km south of Diwandara and 95 km north of Sanandaj city in the Kurdistan province of Iran. Initial calibration and validation of the model were performed using laboratory data. Simulations were conducted with suspended sediment concentrations of 3000, 6000, 9000, and 12,000 ppm to examine the impacts on discharge and key hydraulic parameters such as flow velocity and pressure distribution. The results reveal that as sediment concentration increases, the discharge rate decreases significantly due to higher flow density, which alters both velocity profiles and pressure distributions. At higher concentrations, discharge reduction exceeded 20%, accompanied by notable variations in pressure and flow velocity across different sections of the outlet system. This study highlights the importance of accounting for sediment load in the design and operational management of dam outlet systems, as this factor can significantly influence performance. Future studies could further investigate the impact of varying sediment shapes and sizes on system efficiency.

Keywords

References

Aminian, P., Ahmadi, A., & Emamgholizadeh, S. (2019a). Experimental investigation on the deviated sediment and flow to sediment bypass tunnels (SBTs) using submerged plates. Journal of Hydraulic Structures, 5(2), 18-31.
Aminian, P., Ahmadi, A., & Emamgholizadeh, S. (2019b). Experimental Study of the Effects of Hydraulic and Geometric Parameters of the Sediment Transport Tunnel on the Deviation Flow and Transmitted Sediment. Iranian Journal of Soil and Water Research, 50(2), 505-514.
Aminian, P., Jorabloo, M., & Ahmadi, A. (2023). Numerical Study of the Effects of Inlet Geometry on the Performance of the Sediment Bypass Tunnel using SSIIM Numerical Model. Journal of Hydraulic and Water Engineering, 1(1), 65-75.
Arman, A., Fathi-Moghadam, M., Samadi, H., & Emamgholizadeh, S. (2009). Fall velocity of cohesive sediments in Dez Dam reservoir.
Barnea, D., Shoham, O., Taitel, Y., & Dukler, A. (1985). Gas-liquid flow in inclined tubes: flow pattern transitions for upward flow. Chemical Engineering Science, 40(1), 131-136.
Borodina, L. K. (1969). Aeration behind low-level gates. Power Technology and Engineering, 3(9), 826-834.
Bureau, O. R. (1977). Design of small dams. Govt. Print. Off.
Dargahi, B. (2010). Flow characteristics of bottom outlets with moving gates. Journal of Hydraulic Research, 48(4), 476-482.
Emamgholizadeh, S., Bateni, S. M., & Jeng, D.-S. (2013). Artificial intelligence-based estimation of flushing half-cone geometry. Engineering Applications of Artificial Intelligence, 26(10), 2551-2558.
Emamgholizadeh, S., Bateni, S. M., & Nielson, J. R. (2018). Evaluation of different strategies for management of reservoir sedimentation in semi-arid regions: a case study (Dez Reservoir). Lake and Reservoir Management, 34(3), 270-282.
Emamgholizadeh, S., Bina, M., Fathi-Moghadam, M., & Ghomeyshi, M. (2006). Investigation and evaluation of the pressure flushing through storage reservoir. ARPN Journal of Engineering and Applied Sciences, 1(4), 7-16.
Emamgholizadeh, S., & Fathi-Moghdam, M. (2014). Pressure flushing of cohesive sediment in large dam reservoirs. Journal of Hydrologic Engineering, 19(4), 674-681.
Emamgholizadeh, S., Khademi, N., & Hosini, H. (2020). Prediction of input sediment to the Shirin-Darreh dam reservoir using HEC-RAS numerical model. Journal of watershed management research, 11(21), 208-222.
Emamgholizadeh, S., & Samadi, H. (2008). Desilting of deposited sediment at the upstream of the Dez reservoir in Iran. Journal of Applied Sciences in Environmental Sanitation, 3(1), 25-35.
Fathi-Moghadam, M., Arman, A., Emamgholizadeh, S., & Alikhani, A. (2011). Settling properties of cohesive sediments in lakes and reservoirs. Journal of Waterway, Port, Coastal, and Ocean Engineering, 137(4), 204-209.
Heller, V., Hager, W. H., & Minor, H. E. (2005). Ski jump hydraulics. Journal of Hydraulic Engineering, 131(5), 347-355.
Jabary, A., Hosseini, A., Haghiabi, A. H., Emamgholizadeh, S., & Behnia, A. (2014). Prediction of the sediment load in the river by HEC-RAS. Irrigation and Water Engineering, 4(4), 12-23.
Khatsuria, R. M. (2004). Hydraulics of spillways and energy dissipators. CRC press.
Liu, T. (2014). Modelling air―water flows in bottom outlets of dams KTH Royal Institute of Technology].
Manual, F. D. U. (2011). Flow3D user manual, v9. 4.2, flow science. Inc., Santa Fe, NM.
Rajaratnam, N., & Beltaos, S. (1977). Erosion by impinging circular turbulent jets. Journal of the Hydraulics Division, 103(10), 1191-1205.
Razavi, A. R., & Ahmadi, H. (2017). Numerical modelling of flow in morning glory spillways using FLOW-3D. Civil Engineering Journal, 3(10), 956-964.
Sharma, K. P., Sharma, S., Sharma, S., Sharma, P. K., Swami, R. C., Singh, P. K., & Rathore, G. S. (2007). Mansagar Lake: Past, present and future Proceedings of Taal, 
Speerli, J., & Hager, W. H. (2000). Air-water flow in bottom outlets. Canadian Journal of Civil Engineering, 27(3), 454-462.
Taghavi, M., & Ghodousi, H. (2015). Simulation of flow suspended load in weirs by using Flow3D model. Civil Engineering Journal, 1(1), 37-49.
Te Chow, V. (1959). Open channel hydraulics. McGraw-Hill.
Wilcox, D. C. (1998). Turbulence modeling for CFD. DCW Industries.
Yakhot, V., & Orszag, S. A. (1986). Renormalization group analysis of turbulence. I. Basic theory. Journal of Scientific Computing, 1(1), 3-51.
Journal of Hydraulic and Water Engineering
Volume 2, Issue 1
July 2024
Pages 126-141

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