Scale Effects in Hydraulic Modeling with a Two-Dimensional Numerical Model

Document Type : Research Paper

Authors

1 Graduated Master Student, Department of Water Engineering and Management, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran.

2 Ph.D. Candidate, Department of Water Engineering and Management, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran.

3 Associate Professor, Department of Water Engineering and Management, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran.

4 Professor, Department of Water Engineering and Management, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran.

Abstract

Hydraulic models are often used as a tool for the prediction of the hydrodynamic behavior of flow. But scale effects in the hydraulic modeling process due to deviations of the results from the prototype. This paper discusses to scale effect in the hydraulic flow model. The goal of the research is to investigate the effect of geometric distortion on the flow characteristics and the degree of deviation of the results of distorted models from the prototype, which is done using the two-dimensional numerical model MIKE21. First, the hydrodynamic conditions of the flow were simulated in four models of straight channel, convergent channel, divergent channel and curved channel with four degrees of distortion one (undistorted), two, five and 10. Then, assuming the similarity of the Froude number, the results of the models were compared with the prototype and the relative error in the result of channels was investigated. The results showed that the difference in depth and average velocity in distorted models with prototype is small, but the difference in transverse velocity profile of sloping model with prototype increases with increasing degree of distortion. So that the relative error in transverse velocity modeling in straight, convergent, divergent and curved channels with a degree of G10 was two, 29, 33 and 39 percent, respectively.

Keywords

Main Subjects

References

  1. Baranya, S., & Jozsa, J. (2007). Numerical and laboratory investigation of the hydrodynamic complexity of a river confluence. Periodica Polytechnica Civil Engineering, 51, 3-8.
  2. Bayle, P. M., Beuzen, T., Blenkinsopp, C. E., Baldock, T. E., & Turner, I. L. (2021). A new approach for scaling beach profile evolution and sediment transport rates in distorted laboratory models. Coastal Engineering, 163,
  3. (1999). MIKE 21 curvilinear. April 1999, DHI Water and Environment, Copenhagen, Denmark, User Guide and Scientific Documentation
  4. Erpicum, S., Tullis, B. P., Lodomez, M., Archambeau, P., Dewals, B. J., & Pirotton, M. (2016). Scale effects in physical piano key weirs models. Journal of Hydraulic Research, 54, 692-698.
  5. Fang, H., He, G., Liu, J., & Chen, M. (2008). 3D numerical investigation of distorted scale in hydraulic physical model experiments. Journal of Coastal Research, 41-54.
  6. Fischer, H. B., & Holley, E. (1971). Analysis of the use of distorted hydraulic models for dispersion studies. Water Resources Research, 7, 46-51.
  7. Gabl, R., Gems, B., Plörer, M., Klar, R., Gschnitzer, T., Achleitner, S., & Aufleger, M. (2014). Numerical simulations in hydraulic engineering. Computational engineering.
  8. Gabriele, H., Stefan, H., Schneider, J., & Olsen, N. R. B. (2014). Numerical analysis of synthetic granulate deposition in a physical model study. International Journal of Sediment Research, 29, 110-117.
  9. Haque, M. M., Klaassen, G. J., & Enggrob, H. G. (2006). Scale effects in movable bed models of rivers with dominant suspended load. World Environmental and Water Resource Congress 2006: Examining the Confluence of Environmental and Water Concerns, 2006. 1-13.
  10. Heller, V. (2011). Scale effects in physical hydraulic engineering models. Journal of Hydraulic Research, 49, 293-306.
  11. Heller, V. (2017). Self-similarity and Reynolds number invariance in Froude modelling. Journal of Hydraulic Research, 55, 293-309.
  12. Lai, Y. G. (2010). Two-dimensional depth-averaged flow modeling with an unstructured hybrid mesh. Journal of Hydraulic Engineering, 136, 12-23.
  13. Link, O., Henríquez, S., & Ettmer, B. (2019). Physical scale modelling of scour around bridge piers. Journal of Hydraulic Research, 57, 227-237.
  14. Lu, J., Liao, X., & Zhao, G. (2013). Experimental study on effects of geometric distortion upon suspended sediments in bending channels. Sedimentary Geology, 294, 27-36.
  15. Mcclimans, T., & Gjerp, S. (1978). Numerical study of distortion in a Froude model. Coastal Engineering 1978.
  16. Mcclimans, T., & Saegrov, S. (1982). River plume studies in distorted Froude models. Journal of Hydraulic Research, 20, 15-27.
  17. Patra, K. C., & Kar, S. K. (2000). Flow interaction of meandering river with floodplains. Journal of Hydraulic Engineering, 126, 593-604.
  18. Patra, K. C., Kar, S. K., & Bhattacharya, A. K. (2004). Flow and velocity distribution in meandering compound channels. Journal of Hydraulic Engineering, 130, 398-411.
  19. Savage, B. M., Crookston, B. M., & Paxson, G. S. (2016). Physical and numerical modeling of large headwater ratios for a 15 labyrinth spillway. Journal of Hydraulic Engineering, 142,
  20. Torres, C., Borman, D., Sleigh, A., & Neeve, D. (2018). Investigating scale effects of a hydraulic physical model with 3D CFD. Smart Dams and Reservoirs: Proceedings of the 20th Biennial Conference of the British Dam Society, held at Swansea University from 13th–15th September 2018.
  21. Tullis, B., Crookston, B., & Young, N. (2020). Scale effects in free-flow nonlinear weir head-discharge relationships. Journal of Hydraulic Engineering, 146,
  22. Tullis, B. (2018). Size-Scale Effects of Labyrinth Weir Hydraulics. Daniel Bung, Blake Tullis, 7th IAHR International Symposium on Hydraulic Structures, Aachen, Germany, 15-18 May.
  23. Waldron, R. L. (2008). Physical modeling of flow and sediment transport using distorted scale modeling.
  24. Wang, H., & Chanson, H. (2016). Self-similarity and scale effects in physical modelling of hydraulic jump roller dynamics, air entrainment and turbulent scales. Environmental Fluid Mechanics, 16, 1087-1110.
  25. Zarrati, A., Tamai, N., & Jin, Y. (2005). Mathematical modeling of meandering channels with a generalized depth averaged model. Journal of Hydraulic Engineering, 131, 467-475.
  26. Zhao, G., Visser, P. J., Lu, J., & Vrijling, J. K. (2013). Similarity of the velocity profile in geometrically distorted flow model. Flow Measurement and Instrumentation, 32, 107-110.
Water and Irrigation Management
Volume 12, Issue 2
July 2022
Pages 375-387

Files

Share

How to cite

Statistics