Flow Discharge and Energy Grade-line in Compound Channels

Document Type : Research Paper

Authors

Abstract

In order to explore the structural and hydraulics behavior of rivers and compound channels, discharge and energy grade-line are very important. Dividing a cross sectional shape of those channels to its subsections, e.g. main channel and floodplains, flow discharge is computed for each section and then flow discharge is determined for the whole section. This method is called as Divided Channel Method (DCM) and there is another method called as Simple Channel Method (SCM). On the basis of dividing channel method, some other methods are also developed, where the important one is the method of Exchange Discharge Model (EDM). The method of EDM is developed by using the effects of momentum transfer on the interaction surface between main channel and floodplain. In this research, the flow discharge and energy grade-line are computed for the data collected from the Flood Channel Facility (FCF) in England and elsewhere applying SCM, DCM and EDM methods, in which a C++ computer programing was used. The results show that the EDM method gives lower relative errors compared with the other methods (for establishing stage-discharge curves). Also, using EDM method and HEC-RAS software, the results for computing energy grade-line (e.g.l.), the method of EDM reveals lower relative errors for establishing e.g.l. curves. Two simple linear equations are presented for relative depths including lower and upper than 0.15. It therefore gives dramatic welfare results about 36% for estimating flow discharge and 34% for estimating energy grade-line.
 

Keywords

References

محمدی م.، 1386. هیدرولیک جریان در کانال­ها و رودخانه­ها، (ترجمه، چاپ دوم)، انتشارات دانشگاه ارومیه.
عسگری آ.، 1389. بررسی رفتار هیدرولیکی جریان در کانال­های مرکب، پایان­نامه کارشناسی ارشد، دانشکده فنی و مهندسی دانشگاه ارومیه.
Ackers P, 1993. Stage-discharge functions for two-stage channels: The impact of new research. Journal of Institute Water and Environmental Management 7 (1): 52-61.
Bousmar D, Scherer R and Zech Y, 1998. One-dimensional unsteady flow computation in channels with floodplains. Pp. 205-215. Computational Fluid Mechanics Publications. Southamptom. UK.
Bousmar D and Zech Y, 1999. Momentum transfer for practical flow computation in compound channels. Journal of Hydraulic Engineering, ASCE 125 (7): 696-706
Bousmar D and Zech Y, 2001. Periodic turbulent structures modeling in a symmetric compound channel. Pp. 244-249. Proc. 29th Congress of IAHR, Tsinghua University Press. Beijing, China.
Bousmar D and Zech Y, 2002. Periodic turbulent structures in compound channels. Pp. 177-185.  Conference Proceeding Book River Flow. University of Luvain La Nau, Belgium.
Knight DW, Demetriou JP and Hamed ME, 1983. Hydraulic analysis of channels with floodplains. Pp. 129-144. Proceedings Ins. Conf. on Hydraulic Aspects of Floods and Flood Controls. British Hydromechanics Research Association (BHRA). September, London.
Sellin RHJ, 1964. A labratoary investigation into the interaction between the flow in the channel of the river and that over its floodplain. La Houille Blanche 7: 793-802.
Yuen YHK, 1989. A study of boundary shear stress, flow resistance and momentum transfer in open channels with simple and compound trapezoidal cross-section. PhD Thesis. University of Birmingham, England. 
 
 

Files

Share

How to cite

Statistics