Transverse Velocities and Vortices in Compound Meandering Channel: Effect of Building Arrangement in the Floodplains

Document Type : Research Paper

Authors

1 Department of Civil Eng., Faculty of Eng., Urmia University, P O Box 165, Urmia 57561-15311, Iran.

2 Department of Water Eng., University of Zanjan, Zanjan 45371-38791, Iran.

Abstract

Numerical simulations were carried out in a compound meandering channel to investigate the effect of building arrangements in the floodplain on the flow field in the main channel. Three types of structural arrangements were used: structural obstacles parallel and perpendicular to the flow of the floodplain (MGT and MHT), and checkered structural barriers (MFT). Numerical simulation results showed that the building arrangements in the floodplain can significantly change the transverse velocities and flow angle in the main channel. Near the convex arc of the apex sections (CS1 and CS7), the transverse flow velocity increased by changing the building arrangements from parallel to the floodplain flow (MGT1) to perpendicular to the floodplain flow (MHT1) (517% increase), but in the center of the main channel in the middle section (CS4), the transverse flow velocity decreases with the change of the arrangement from the parallel state (MGT1) to the perpendicular state to the floodplain flow (MHT1) (47% decrease). In the CS4, the maximum transverse flow velocity in cases MFT1, MGT1 and MHT1 decreases by 84%, 49% and 80% on average respectively, compared to the smooth floodplain (MAT). In the center of the CS4, the change of arrangement has the greatest effect on the flow angle, so that the lowest flow angle is observed for cases with the arrangement of buildings perpendicular to the floodplain flow and checkered (MHT and MFT). Also, in the middle section, the strength of vortices rotation increases significantly in the case of MGT1 compared to the case of MHT1.

Keywords

Main Subjects


  1. Knight DW, Demetriou JD, (1983). Floodplain and main channel flow interaction. Journal of Hydraulic Engineering, 109(8), 1073–1092.
  2. Liu C, Wright N, Liu X, Yang K, (2014). An analytical model for lateral depth-averaged velocity distributions along a meander in curved compound channels. Advances in Water Resources, 74, 26-43.
  3. Shiono K, Muto Y, (1998). Complex flow mechanisms in compound meandering channels with overbank flow. Journal of Fluid Mechanics, 376, 221–261.
  4. Ismail Z, (2007). A study of overbank flows in non-vegetated and vegetated floodplains in compound meandering channels. Dissertation for the Doctoral Degree. Loughborough: University of Loughborough.
  5. Zhang HT, Dai WH, da Silva AMF, Tang H, (2022). Numerical study on resistance to flow in meandering channels. Journal of Hydraulic Engineering, 148, 1–14.
  6. Pu JH, (2019). Turbulent rectangular compound open channel flow study using multi-zonal approach. Environmental Fluid Mechanics, 19(3), 785-800.
  7. Pu JH, (2022). Editorial: Environmental Hydraulics, Turbulence and Sediment Transport. Fluids (MDPI), 7(48), 1-2.
  8. Moncho-Esteve I, Palau-Salvador G, García-Villalba M, Muto Y, Shiono K, (2018). A numerical study of the complex flow structure in a compound meandering channel. Advances in Water Resources, 116, 95–116.
  9. Liu C, Shan Y, Liu X, Yang K, Liao H, (2016). The effect of floodplain grass on the flow characteristics of meandering compound channels. Journal of Hydrology, 542, 1-17.
  10. Tsujimoto T, (1992). Spectral analysis of velocity and water surface fluctuations appearing in an open channel with vegetated and non-vegetated regions in a cross-section. In: Proceedings of the sixth IAHR International Symposium on Stochastic Hydraulics, IAHR, Taipei.
  11. Zhang HT, Dai WH, da Silva AMF, Tang HW, (2021). Numerical model for convective flow in meandering channels with various sinuosities. Journal of Hydraulic Engineering, 147, 04021042.
  12. Mahato RK, Dey S, Ali SZ, (2022). Planform evolution of a sinuous channel triggered by curvature and autogenic width oscillations due to generic grain transport. Physics of Fluids, 34, 044110.
  13. Wang M, Avital EJ, Bai X, Ji C, Xu D, Williams JJR, Munjiza A, (2020). Fluid–structure interaction of flexible submerged vegetation stems and kinetic turbine blades. Computational Particle Mechanics, 7, 839–848.
  14. Pu JH, Pandey M, Li J, Satyanaga A, Kundu S, Hanmaiahgari PR, (2022). Editorial: Urban Fluvial and Hydro-Environment System. Frontiers in Environmental Science, 10(1075282)1-3.
  15. Tang H, Tian Z, Yan J, Yuan S, (2014). Determining drag coefficients and their application in modelling of turbulent flow with submerged vegetation. Advances in Water Resources, 69, 134–145.
  16. Pu JH, Hussain A, Guo Y, Vardakastanis N, Hanmaiahgari PR, Lam D, (2019). Submerged Flexible Vegetation Impact toward Open Channel Flow Velocity Distribution: An Analytical Modelling Study on Drag and Friction. Water Science Engineering, 12(2), 121-128.
  17. Kundu S, Chattopadhyay T, Pu JH, (2022). Analytical models of mean secondary velocities and stream functions under different bed-roughness configurations in wide open-channel turbulent flows. Environmental Fluid Mechanics, 22(1), 159-188.
  18. Pan Y, Li Zh, Yang K, Jia D, (2019). Velocity distribution characteristics in meandering compound channels with one-sided vegetated floodplains. Journal of Hydrology, 578, 1-11.
  19. Naghavi M, Mohammadi M, Mahtabi G, (2022). An experimental evaluation of the blocks in floodplain on hydraulic characteristics of flow in a meandering compound channel. Journal of Hydrology, 612, 1-20.
  20. Naghavi M, Mohammadi M, Mahtabi G, (2023). The effect of building arrangement on the flow characteristics in meandering compound channels. Journal of Environmental Management, 331(1), 117288.
  21. Shukla DR, Shiono K, (2008). CFD modelling of meandering channel during floods. Proceedings of the Institution of Civil Engineers-Water Management, 161, 1–12.
  22. Sanjou M, Nezu I, (2010). Large eddy simulation of compound open-channel flows with emergent vegetation near the floodplain edge. Journal of Hydrodynamics, 22(5), 582-586.
  23. Naghavi M, Mohammadi M, Mahtabi G, Abraham J. (2023). Experimental assessment of velocity and bed shear stress in the main channel of a meandering compound channel with one-sided blocks in floodplain. Journal of Hydrology, 617, 129073.
  24. Naghavi M, Mohammadi M. A, Mahtabi G. (2019). Flow Velocity in Meandering Compound Channel under the Influence of Sinusoidal Change. Modares Civil Engineering journal, 19(5), 208-219.
  25. Naghavi M, Mohammadi M, Mahtabi G. (2020). Turbulence Intensity and Boundary Shear Stress in Meandering Compound Channel under the Influence of Sinusoidal Changes. Journal of Modeling in Engineering, 18(60), 53-69.
  26. Naghavi M, Mohammadi M, Mahtabi G. (2021). Numerical simulation of flow velocity distribution and shear stress in meandering compound channels. Iranian Water Researches Journal, 15(1), 23-34.
  27. Naghavi M, Mohammadi M, Mahtabi G. (2021). Transverse Flow Characteristics in the Meandering Compound Channels. Amirkabir Journal of Civil Engineering, 53(8), 3499-3516.
  28. Naghavi M, Mohammadi M, Mahtabi G. (2021). On the effect of relative flood depth on flow hydraulics in meandering compound channels. Irrigation and Water Engineering, 11(3), 55-78.
  29. Naghavi M, Mohammadi M, Mahtabi G. (2023). The effect of structures density in the banks of meandering rivers on the flow characteristics during floods. Journal of Water and Irrigation Management.
  30. Pu JH, Shao S, Huang Y, (2014). Numerical and experimental turbulence studies on shallow open channel flows. Journal of Hydro-environmental Research, 8(1), 9-19.
  31. Pu JH, (2015). Turbulence Modelling of Shallow Water Flows using Kolmogorov Approach. Computational Fluids, 115, 66-74.
  32. Yakhot V, Thangam S, Gatski TB, Orszag SA, Speziale CG, (1992). Development of turbulence models for shear flows by a double expansion technique. Physics Fluids, 4(7), 1-24.
  33. Xu D, Bai Y, Munjiza A, Avital E, Williams J, (2013). Investigation on the Characteristics of Turbulent Flow in a Meandering Open Channel Bend Using Large Eddy Simulation. In: Proceedings of 2013 IAHR World Congress, IAHR, China.
  34. Van CP, Deleersnijder E, Bousmar D, Soares-Frazão S, (2014). Simulation of flow in compound open-channel using a discontinuous Galerkin finite-element method with Smagorinsky turbulence closure. Journal of Hydro-environmental Research, 8(40), 396-409.
  35. Brevis W, García-Villalba M, Niño Y, (2014). Experimental and large eddy simulation study of the flow developed by a sequence of lateral obstacles. Environmental Fluid Mechanics, 14, 873–893.
  36. De Marchis M, Napoli E, (2008). The effect of geometrical parameters on the discharge capacity of meandering compound channels. Advances in Water Resources, 31, 1662–1673.
  37. Shan Y, Huang S, Liu C, Guo Y, Yang K, (2018). Prediction of the depth-averaged two-dimensional flow direction along a meander in compound channels. Journal of Hydrology, 565, 318–330.
  38. Liu X, Zhou Q, Huang S, Guo Y, Liu C, (2018). Estimation of flow direction in meandering compound channels. Journal of Hydrology, 556, 143-153.