توزیع سرعت متوسط عمقی در کانال‌های صاف ذوزنقه‌ای و مستطیلی با بهترین مقطع هیدرولیکی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانش¬آموخته کارشناسی ارشد مهندسی عمران، دانشگاه صنعتی اصفهان

2 دانشیار، دانشکده مهندسی عمران، دانشگاه صنعتی اصفهان

چکیده

رابطه‌های عمومی تخمین توزیع سرعت متوسط عمقی در کانال‌های باز با مقطع ذوزنقه‌ای، نتایج مناسبی ارائه نمی‌کنند. از این‌رو در این مقاله به ارائه روشی جدید برای تخمین این پارامتر در کانال‌های صاف ذوزنقه‌ای با بهترین مقطع هیدرولیکی پرداخته ‌شد. در این روش، توزیع سرعت متوسط عمقی با استفاده از رابطة تنش برشی جداره محاسبه ‌شد. برای واسنجی مدل تحلیلی، از نتایج مدل‌سازی آزمایشگاهی استفاده شد. نتایج حاصل از مقایسه مدل تحلیلی و آزمایشگاهی نشان می‌دهد که روش ارائه شده از دقت قابل قبولی برخوردار است.

کلیدواژه‌ها


عنوان مقاله [English]

Depth-averaged Velocity Distribution in Smooth Trapezoidal and Rectangular Open Channels with the Best Hydraulic Section

نویسندگان [English]

  • Faemeh Farshi 1
  • Abdoreza Kabiri Samani 2
چکیده [English]

General equations for predicting depth-averaged velocity in open channels are not well suited for trapezoidal open channels. In this study, an innovative method is developed for predicting the depth-averaged velocity distributions in smooth trapezoidal open channels with the best hydraulic section. Depth-averaged velocity was obtained using the boundary shear stress obtained in the present study. To calibrate the present analytical results, an experimental investigation was also performed. Analytical results compared well with the experimental data.

کلیدواژه‌ها [English]

  • open channel
  • Depth-averaged velocity
  • Boundary Shear Stress
1- Ghosh, S.N., and Roy, N. (1970). “Boundary shear distribution in open channel flow.” J. Hyd. Div., 96(4), 967-994.
2- Knight, D.W., AlHamid, A.A.I., and Yuen, K.W.H. (1992). “Boundary shear in differentially roughened trapezoidal channels. ” Falconer, K., and Shiono, R.G.S. (Eds.) Hydraulic and environmental modeling: Estuarine and river waters.
3- Tominaga, A., Nezu, I., Ezaki, K., and Nakagawa, H. (1989). “Three-dimensional turbulent structure in straight open channel flows.” J. Hyd. Res., 27(11), 149-173.
4- Guo, J., and Julien, P.Y., (2001). “Turbulent velocity profiles in sediment laden flows.” J. Hyd. Res., 39, (1), 11-23.
5- Guo, J., and Julien, P.Y. (2005). “Shear stress in smooth rectangular open-channel flows.” J. Hydr.Eng., 131(1), 30-37.
6- Riahi Modvar, H., and Ayyoubzadeh, S. A. (2008). “Estimating longtitudal dispersion  coefficient pollutants using adaptive neuro-fuzzy inference system.” J. Water and Wastewater, 67, 34-47 (In Persian).
7- Farshi, F. (2011). “Depth-averaged velocity and boundary shear stress in channels with the best trapezoidal and rectangular hydraulic sections using conformal mapping method.” MSc. Thesis, Isfahan University of Technology, Isfahan. (In Persian)
8- Farshi, F., Kabiri- Samani, A. R., and Chamani, M. R. (2011). “Mean bed and side-wall shear stress on smooth trapezoidal open channels with the best hydraulic sections using conformal mapping method.” 6th National Congress on Civil Engineering, University of Semnan, Semnan, Iran. (In Persian)
9- Sooky, A.A. (1969). “Longitudinal dispersion in open channels.” J. Hydr. Div., 95 (4),1327-1346.
10- Wark, J.B., Samuels, P.G., and Ervine, D.A. (1990). “A practical method of estimating velocity and discharge in a compound channel.” White, W.R. (Ed.,) River Flood Hydraulics, Wiley, New York.
11- Seo, I.W., and Baek, K.O. (2004). “Estimation of the longitudinal dispersion coefficient using the velocity profile in natural streams.” J. Hyd. Eng., 130(3), 227-236.
12- Shiono, K., and Knight, D.W. (1988). “Two-dimensional analytical solution for a compound channel.” Proc., 3rd Int. Symp. on Refined Flow Modeling and Turbulence Measurements, Tokyo, Japan.
13- Shiono, K., and Knight, D.W. (1991). “Turbulent open-channel flows with variable depth across the channel.” J. Fluid Mech., 222, 617-646.
14- Ervine, D.A., Babaeyan-Koopaei, K., and Sellin, R.H.J. (2000). “Two dimensional solution for straight and meandering over bank flows.” J. Hyd. Eng., 126(9), 653-669.
15- Maghrebi, M.F. (2003). “Discharge estimation in flumes using a new technique for the production of isovel contours.” Proceeding of International Conference on Civil and Environment Engineering ICCEE, Hiroshima, Japan, 147-156.
16- Wilkerson, G.V., and McGahan, J.L. (2005). “Depth-averaged velocity  distribution  in straight trapezoidal channels.” J. Hyd. Eng., 131(6), 509-512.
17- Knight, D.W., Omran, M., and Tang, X. (2007). “Modeling depth-averaged velocity and boundary shear in trapezoidal channels with secondary flows.” J. Hydr. Eng., 133(1), 39-47.
18- Tang, X., and Knight, D.W. (2008). “A general model of lateral depth-averaged velocity distributions for open channel flows.” J. Advances in Water Resources, 31, 846-857.
19- Rezaei, B., and Knight, D.W. (2009). “Application of the Shiono and Knight method in compound channels with non-prismatic floodplains.”J. Hyd. Res., 47(6), 716-726.
20- Givehchi, M., and Maghrebi, M.F. (2009). “Estimation of depth-averaged velocity and boundary shear stress in a triangular open channel.” J. Water and Wastewater, 2, 71-80. (In Persian)
21- Givehchi, M., Maghrebi, M.F., and Abrishami, J. (2009). “Application of depth-averaged velocity profile for estimation of longitudinal dispersion in rivers.” J. Water and Wastewater, 72, 91-96. (In Persian)
22- Lundgren, H., and Jonsson, I.G. (1964). “Shear and velocity distribution in shallow channels.” J. Hyd. Div., 90(1), 1-21.
23- Einstein, H. A. (1942). “Formulas for the transformation of bed-load.” Trans. ASCE, 107, 561-597.  
24- Chiu, C.L., and Chiou, J.D. (1986). “Structure of 3-D flow in rectangular open-channels.” J. Hyd. Eng., 112(11), 1050-1068.
25- Chamani, M.R., Dehghani, A.A., Beirami, M.K., and Gholipoor, R.A. (2010). Fluid Mechanics, Isfahan University of Technology., Isfahan. (In Persian)
26- Yang, S.Q. (2010). “Depth-averaged shear stress and velocity in open channel flows.” J. Hyd. Eng., 136 (11) 952-958.