نوع مقاله: مقاله پژوهشی
نویسندگان
1 دانشجوی دکتری سازه‌های آبی، گروه مهندسی آبیاری و آبادانی پردیس کشاورزی و منابع طبیعی دانشگاه تهران
2 دانشیار گروه مهندسی آبیاری و آبادانی دانشکده مهندسی کشاورزی و فناوری، پردیس کشاورزی و منابع طبیعی، دانشگاه تهران
چکیده
کلیدواژه‌ها
عنوان مقاله [English]
نویسندگان [English]
Sluice gates are designed and used in Ogee spillways with high height (regulator dams) or low height (as sill) for better controlling the flow. In latter case, according to different combinations of weir geometry, gate opening, upstream and downstream flow depths, four different flow conditions are recognizable: (a) free uncontrolled flow, (b) submerged uncontrolled flow, (c) free controlled flow, and (d) submerged controlled flow. Determination of change threshold of these flow condition is useful for choosing the proposed discharge equations in any situation. In current research, using the experimental data gathered from two Ogee spillways with different height in this program and using the data gathered from typical spillway structures in central and southern Florida water-control project, different equations for determining the change threshold and flow discharge in four different flow conditions are developed. In free uncontrolled flow condition, the proposed discharge equation has an average relative error of 1.95% while in free and submerged controlled flow condition, the proposed discharge equations have the average relative errors of 2% and 5% respectively. Results showed that the change threshold of uncontrolled flow into controlled flow occurs when upstream flow depth increases about 1.46 times the gate opening. Furthermore, the relative submergence threshold and flow discharge increase by increasing the downstream flow depth and decreasing the upstream flow depth.
کلیدواژه‌ها [English]
Alminagorta, O. and Merkley, P. 2009. Transitional flow between orifice and nonorifice regimes at a rectangular sluice gate. J. Irrig. Drain. Eng. 135(3): 382-387.
Anon. 1963. Typical spillway structure for central and southern Florida water-control project. U. S. Army Engineer Waterways Experiment Station. Vicksburg, Mississippi.
Anon. 1972. Overflow spillways, stage-discharge relation for uncontrolled flow. U. S. Army Engineer Waterways Experiment Station. Hydraulic Design Chart 111-3/3, Vicksburg, Mississippi.
Anon. 1987. Design of small dams. U.S. Bureau of Reclamation (USBR). U.S. Government Printing Office, Washington, D.C.
Ansar, M. and Chen, Z. 2009. Generalized flow rating equations at prototype gated spillways. J. Hydraul. Eng. 135(7): 602-608.
Chen, Z. and Ansar, M. 2017. Application of the generalized flow equation to all flow conditions at spillways. World Environmental and Water Resources Congress. May 21–25. Sacramento, California, USA.
Hager, W. and Bremen, R. 1988. Plane gate on standard spillway. J. Hydraul. Eng. 114(11): 1390-1397.
Hussain, S., Hussain, A. and Ahmad, Z. 2014. Discharge characteristics of orifice spillway under oblique approach flow. Flow Meas. Instrum. 39(1): 9-18.
Multer, R. H. 1963. Discharge rating curves for vertical lift gates on spillway crests. U. S. Army Engineer Waterways Experiment Station. Paper No. 2-606. Vicksburg, Mississippi.
Negm, A. M. 1995. Free and submerged flow below sluice gate with sill. Adv. Hydrosci. Eng. Part A:
283-300.
Tullis, B. 2011. Behavior of submerged ogee crest weir discharge coefficients. J. Irrig. Drain. Eng. 137(10): 677-681.
Tullis, B. and Neilson, J. 2008. Performance of submerged ogee-crest weir head-discharge relationships. J. Hydraul. Eng. 134(4): 486–491.
Zeng, J., Zhang, L., Ansar, M. and Damisse, E. 2017a. Applications of computational fluid dynamics to flow ratings at prototype spillways and weirs. I: Data generation and validation. J. Irrig. Drain. Eng. 143(1): 04016072 (1-13).
Zeng, J., Zhang, L., Ansar, M. and Damisse, E. 2017b. applications of computational fluid dynamics to flow ratings at prototype spillways and weirs. II: Framework for planning, data assessment, and flow rating. J. Irrig. Drain. Eng. 143(1): 04016073 (1-13).
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