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Flow Structures in Trapezoidal Compound Channels with Different Side Slopes of Main Channel

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Abstract

In a trapezoidal compound channel, the side slope of the main channel has a significant effect on the flow structure and the momentum exchange in the connecting region of the main channel and the floodplain. The three-dimensional compound channel flows with the 90°, 60°, 45° and 30° side slopes of main channel were simulated by solving the Navier–Stokes equations with the Reynolds Stress Model (RSM). The effects of main channel side slopes on the secondary currents, streamwise velocities, bed shear stresses, Reynolds shear stresses, turbulent intensities and the turbulence anisotropy were analyzed. The results show that (1) the secondary currents are modified as a result of the variation of the turbulence anisotropy \((\overline {{w^{\prime 2}}} - \overline {{v^{\prime 2}}} )\), which is caused by the varied momentum exchange between the main channel and the floodplain; (2) as the main channel side slope decreases, the intensity of the secondary currents and their direct influence on the streamwise velocity, the bed shear stress, the Reynolds shear stress and the turbulent intensity becomes weaker. The deceleration of the streamwise velocity in the connecting region becomes less remarkable. The bed shear stresses tend to follow a more uniform distribution and are found to have one drop at the bottom of the main channel sidewall and the other drop at the edge of the floodplain when the side slope of the main channel is not vertical. These are different from the case of the vertical main channel side wall, in which only one minimum and one maximum values are observed at the interface region. The total magnitude of the turbulence intensity near the junction edge increases by a much smaller extent. The discharge ratio of the main channel increases while that of the floodplain decreases. The magnitude difference of \(- \overline {{{{u}}^\prime }{w^\prime }}\) between the main channel and the floodplain in the interface region decreases, which implies the momentum transport becomes weaker due to the diminished secondary currents. These results will contribute for designing the most optimum cross-section shape for flood discharge of the compound channel.

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References

  1. Tominaga A, Nezu I (1991) Turbulent structure in compound open-channel flows. J Hydraul Eng 117(1):21–41

    Article  Google Scholar 

  2. Sayed-Abdul-Hamid S, Sayed-Hamed S, Hamed S (2016) Accuracy of numerical simulation in asymmetric compound channels. Int J Civ Eng. doi:10.1007/s40999-016-0113-3.

    Google Scholar 

  3. Ardeshir A (2004) Mathematical model of river bed variation prediction at Alluvial rivers under gradually varied flow condition. Int J Civ Eng 2(1):8–22

    MathSciNet  Google Scholar 

  4. Rezaei B, Knight DW (2009) Application of the shiono and knight method in compound channels with non-prismatic floodplains. J Hydraul Res 47(6):716–726

    Article  Google Scholar 

  5. Ackers P (1993) Flow formulae for straight two-stage channels. J Hydraul Res 31(4):509–531

    Article  Google Scholar 

  6. Babaeyan-Koopaei K, Ervine DA, Carling PA, Cao Z (2002) Velocity and turbulence measurements for two overbank flow events in River Severn. J Hydraul Eng ASCE 128(10):891–900

    Article  Google Scholar 

  7. Ackers P (1993) Stage-discharge functions for two-stage channels: the impact of new research. J Water Environ Manag 77(1):52–60

    Article  Google Scholar 

  8. Knight DW, Sellin RHJ (1987) The SERC flood channel facility. J Inst Water Environ Manag 1(2):198–204

    Article  Google Scholar 

  9. Güllü H (2012) Prediction of peak ground acceleration by genetic expression programming and regression: a comparison using likelihood-based measure. Eng Geol 141–142:92–113.

    Article  Google Scholar 

  10. Güllü H, Erçelebi A (2007) Neural network approach for attenuation relationships: an application using strong ground motion data from Turkey. Eng Geol 3–4(93):65–81.

    Article  Google Scholar 

  11. Yang KJ (2006) Flow resistance and sediment transport in compound channels (Doctoral dissertation). Sichuan University, Chengdu.

    Google Scholar 

  12. Yang ZH, Gao W, Huai WX (2010) Study on the secondary flow coefficient of over bank flow. Appl Math Mech 6:681–689

    Google Scholar 

  13. Yang ZH, Gao W, Huai WX (2010) Secondary flow coefficient of over bank flow. Appl Math Mech 31:709–718. doi:10.1007/s10483-010-1305-9.

    Article  MATH  Google Scholar 

  14. Yang KJ, Liu XN, Cao SY (2014) Stage-Discharge prediction in compound channels. J Hydraul Eng 140(4):1–8

    Article  Google Scholar 

  15. Bottacin-Busolin A, Marion A (2010) Combined role of advective pumping and mechanical dispersion on time scales of bed form-induced hyporheic exchange. Water Resour Res 46(8):W08518. doi:10.1029/2009WR008892

    Article  Google Scholar 

  16. Kang H, Choi S-U (2005) 3D numerical simulation of compound open-channel flow with vegetated floodplains by Reynolds Stress Model. KSCE J Civ Eng 9(1):7–11

    Article  Google Scholar 

  17. Jing H, Guo Y, Li C, Zhang J (2009) “Three-dimensional numerical simulation of compound meandering open channel flow by the Reynolds stress model. Int J Num Methods Fluids 59(8):927–943. DOI:10.1002/fld.1855

    Article  MathSciNet  MATH  Google Scholar 

  18. Daly BJ, Harlow FH (1970) Transport equations in turbulence. Phys Fluids 13:2634–2649

    Article  Google Scholar 

  19. Cardenas MB, Wilson JL (2007) Effects of current–bed form induced fluid flow on the thermal regime of sediments. Water Resour Res. doi:10.1029/2006WR005343

    Google Scholar 

  20. Rameshwaran P, Naden PS (2003) Three-dimensional numerical simulation of comound channel flows. J Hydraul Eng-ASCE 129:645–652

    Article  Google Scholar 

  21. Salehin M (2004) “Hydrodynamics of hyporheic exchange for complex natural streambed topography”, channel geometry and sediment structure, Ph.D. thesis; Northwestern University, USA.

  22. FLUENT. FLUENT 6.3 Documentation (2006). Retrieved from http://my.fit.edu/itresources/manuals/fluent6.3/help/index.htm. Last Accessed 28 Oct 2010. Fluent Inc., Lebanon,

  23. Launder BE, Spalding DB (1974) The numerical computation of turbulent flows. Comput Methods Appl Mech Eng 3:269–289

    Article  MATH  Google Scholar 

  24. Tominaga A, Nezu I, Ezaki K (1989) Three-dimensional turbulent structure in straight open channel flows. J Hydraul Res 27(1):149–173

    Article  Google Scholar 

Download references

Acknowledgements

This study was supported by the National Natural Science Foundation of China under Grant number 41323001; the Priority Academic Program Development of Jiangsu Higher Education Institutions under Grant number SYS1401; and the National Key Research and Development Program of China under Grant number 2016YFC0402605.

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Authors and Affiliations

  1. State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing, China

    Yang Xiao

  2. College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing, China

    Yang Xiao, Nairu Wang & Jieqing Liu

  3. Department of Engineering, University of Cambridge, Cambridge, UK

    Dongfang Liang

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  1. Yang Xiao
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  2. Nairu Wang
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  3. Dongfang Liang
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  4. Jieqing Liu
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Correspondence to Yang Xiao.

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Xiao, Y., Wang, N., Liang, D. et al. Flow Structures in Trapezoidal Compound Channels with Different Side Slopes of Main Channel. Int J Civ Eng 16, 823–835 (2018). https://doi.org/10.1007/s40999-017-0212-9

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  • DOI: https://doi.org/10.1007/s40999-017-0212-9

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