Prediction of Total and bedform Roughness Coefficient in Alluvial Channels Based on Experimental Data via Gaussian Process Regression Method

Document Type : Original Article

Authors

1 Civil, IAU

2 Department Hydraulic Engineering, Faculty of Civil Engineering, Tabriz University, Iran

Abstract

Understanding the flow and turbulence characteristics in movable open channels with bedforms is of substantial importance for the management of rivers as well as design and operation of hydraulic structures. Dunes are one of the most important bedforms and have significant impact on the characteristics of turbulence. So far numerous studies have been down about hydraulic resistance in open channels with bedforms, however, due to the impact of various parameters on the roughness coefficient, the exact estimation of this parameter is difficult. In this research, using the data of experiments carried out at the Hydraulic Laboratory of University of Tabriz with two different gradation and two channel widths, flow resistance due to bedform was studied. Also, by combining these data with laboratory data from other researchers, using Gaussian Process Regression (GPR) different models were defined and investigated. The obtained results from the experiments showed that in investigating the effect of hydraulic parameters on flow resistance, Reynolds number showed a better correlation with flow resistance in comparison with other hydraulic parameters. Also, the obtained results from the developed models proved desired capability of GPR method in predicting roughness coefficient and it was observed that both flow and sediment particles characteristics are effective in estimating roughness coefficient. The results of the superior model sensitivity analysis showed that the Reynolds number has the most significant impact in predicting the roughness coefficient.

Keywords

References

ثاقبیان، س.م. 1396. بررسی روند تغییرات ضریب مقاومت جریان در بسترهای فرسایش­پذیر، پایان نامه دکتری تخصصی، دانشکده عمران، دانشگاه تبریز.
Anderson, A. G., Paintal, A. S. and Davenport, J. T. 1970. Tentative design procedure for riprap lined channel. Report no. 108, Hihgway Research Bord, National Academy of Sciences-National Academy of Engineering, Washington D C, USA, 75pp.
ASCE, Task Committee on Application of Artificial Neural Networks in Hydrology. 2000. Artificial Neural Networks in hydrology. I: Preliminary concepts. J. Hydrologic Eng, ASCE. 5(2): 115-123.
Guy, H. P., Simons, D. B. and Richardson, E. V. 1966. Summary of alluvial channel data from flume experiments, 1956-61(No. 462-I).
Henderson, F. M. 1966. Open Channel Flow. Macmillan, New York.
Heydari, H., Zarrati, A. R. and Karimaee Tabarestani, M. 2014. Bedform characteristics in a live bed alluvial channel, Scientia Iranica, Transactions A: Civil Engineering. 21(6): 1773-1780.
Meyer-Peter, E. and Müller, R. 1948. Formulas for bed-load transport. Proc. 2nd Meeting IAHR, Stockholm, 39–64.
Strickler, A. 1923. Beitrage zur Frage der Geschwindigheits-formel und der Rauhegkeitszahlen fur Strome, Kanale und geschlossene Leitungen. (Some contributions to the problem of the velocity formula and roughness factors for rivers, canals, and closed conduits.): Bern, Switzerland, Mitt. Eidgeno assischen Amtes Wasserwirtschaft, no. 16.
Tuijnder, A. P. and Ribberink, J. S. 2012. Experimental observation and modelling of roughness variation due to supply-limited sediment transport in uni-directional flow. Journal of Hydraulic Research. 50(5): 506-520.
Van der Mark, C. F., Blom, A. and Hulscher, S. J. 2008. Quantification of variability in bedform geometry. Journal of Geophysical research: Earth Surface, 113.
Williams, G. P. 1970. Flume Width and Water Depth Effects in Sediment Transport Experiments. U.S. Geological Survey, Professional Paper 562-H.
Yang, S. Q., Tan, S. K. and Lim, S. Y. 2005. Flow resistance and bed form geometry in a wide alluvial channel . Water Resource Research. 41(9): 1-8.
Iranian Journal of Irrigation & Drainage
Volume 13, Issue 2 - Serial Number 74
July and August 2019
Pages 437-449

Files

Share

How to cite

Statistics