A numerical simulation of overlay effect of rigid vegetation in a straight open channel by OpenFOAM

Document Type : Research Paper


1 Ph.D. Student, Department of Water Eng., & Hydraulic Structures, Faculty of Civil Engineering, Semnan University, Semnan, Iran.

2 Associate Professor, Department of Civil Engineering (Water and Hydraulic Structures), Faculty of Engineering, Urmia University, Urmia, Iran,

3 Associate Professor, Department of Water Eng., & Hydraulic Structures, Faculty of Civil Engineering, Semnan University, Semnan, Iran.


In order to understand the mechanism of flow patterns in vegetated channels, the flow located in a rectangular channel was numerically investigated by using OpenFOAM software. Firstly, two solvers of that software (i.e. icoFoam and pimpleFoam) were used to calculate the velocity profiles in both longitudinal and cross-sectional directions for four selected sections in a rectangular channel with a square cylinder. By comparing the simulation results with the available data, the icoFoam solver with a better performance (six Percent Error) was selected for the next developed model. A new model was then created with two tandem square cylinders with spacing ratios of two and a half and five. Flow patterns, velocity distribution and pressure characteristics in the channel with different inlet flow velocities were investigated for two cases. It was observed that a flow field disturbance occurred in all simulations and the current changed from steady state to unsteady one at a critical velocity. This instability occurred in a distance between the cylinders for the spacing ratio of five at an average Reynolds number of eight, while for the ratio of two and a half it is occurred at an average Reynolds number of 32. The maximum values ​​of longitudinal and transverse velocity timelines in a period of 200 seconds for four states (including two Reynolds numbers and two different spacing ratios) were plotted in two spatial ranges and fully investigated. According to the results, it can be said that the overlap has an important role on the flow characteristics in tandem arrangements and by increasing the distance ratio between the cylinders by 55 percent, the critical velocity value decreases by 74 percent.


Main Subjects

  1. Adeeb, E., Haider, B. A., & Sohn, C. H. (2018). Flow interference of two side-by-side square cylinders using IB-LBM Effect of corner radius. Results in Physics 10, 256-263.
  2. Ali, K. H., & Karim, O. (2002). Simulation of flow around piers. Hydraul. Res., 40, 161-174.
  3. Anjum, N., & Tanaka, N. (2019). Study on the flow structure around discontinued vertically layered vegetation in an open channel. of Hydrodynamics. https://doi.org/10.1007/s42241-019-0040-2
  4. Bai, H., & Li, J. W. (2011). Numerical Simulation of Flow Over a Circular Cylinder at Low Reynolds Number. Advanced Material Res, 255-260: 942.
  5. Breuer, M., Bernsdorf, J., Zeiser, T., & Durst, F. (2000). Accurate computations of the laminar flow past a square cylinder based on two different methods: lattice-Boltzmann and finite-volume. International Journal of Heat and Fluid Flow, 21, 186-196.
  6. Butt, U., & Egbers, C. (2013). Aerodynamic Characteristics of Flow Over Circular Cylinders with Patterned Surface. International Journal of Materials, Mechanics and Manufacturing, 1(2), 121.
  7. Cao, S., & Tamura, Y. (2008). Flow Around a Circular Cylinder in Linear Shear Flows at Subcritical Reynolds Number. of Wind Engineering and Industrial Aerodynamics, 96,10-11: 1961.
  8. Cao, Y., Tamura, T., & Kawai, H. (2020). Spanwise resolution requirements for the simulation of high-Reynolds-number flows past a square cylinder. Computers and Fluids, 196, 104320. https://doi.org/10.1016/j.compfluid.2019.104320
  9. Curran, J. C., & Hession, W. C. (2013). Vegetative impacts on hydraulics and sediment processes across the fluvial system, of Hydrology, 505, 364-376.
  10. Den Hartog, J. P. (2013). Mechanical Vibrations. Dover Publications. ISBN: 0486131858.
  11. Diwivedi, A. R., Dhiman, A., & Sanyal, A. (2022). Stratified Shear-Thinning Fluid Flow Past Tandem Cylinders in the Presence of Mixed Convection Heat Transfer With a Channel-Confined Configuration. Fluids Eng., 144(5), 051301. https://doi.org/10.1115/1.4052473
  12. Dupuis, V., Proust, S., Berni, C., & Paquier, A. (2016). Combined effects of bed friction and emergent cylinder drag in open channel flow. Environmental Fluid Mechanics. doi: 10.1007/s10652-016-9471-2
  13. Durao, D. F. G., Gouveia, P. S. T., & Pereira, J. C. F. (1991). Velocity characteristics of the flow around a square cross section cylinder placed near a channel wall. Experiments in Fluids, 11, 341-350.
  14. Etminan, A., Moosavi, M., & Ghaedsharifi (2011). Determination of flow configuration and fluid forces acting on two tandem square cylinders in cross-flow and its wake patterns. International Journal of Mechanics, 5(2).
  15. Gamet, L., Scala, M., Roenby, J., Scheufler, H., & Pierson, J. L. (2020). Validation of volume-of-fluid OpenFOAM® isoAdvector solvers using single bubble benchmarks. Computers & Fluids, 213. https://doi.org/10.1016/j.compfluid.2020.104722
  16. Gao, Y., Chen, W., Wang, B., & Wang, L. (2019). Numerical simulation of the flow past six‐circular cylinders in rectangular configurations. Journal of Marine Science and Technology. https://doi.org/10.1007/s00773-019-00676-7
  17. Gera, B., Sharma, P. K., & Singh, R. K. (2010). CFD Analysis of 2D Unsteady Flow Around a Square Cylinder. International J. of Applied Engineering Research, 1(3), 602.
  18. Ghisalberti, M., & Nepf, H. M. (2002). Mixing layers and coherent structures in vegetated aquatic flows, Geophys. Re, 107 (C2) 1-11.
  19. Greenshields, C. J. (2019). OpenFOAM User Guide version 7, OpenFOAM Foundation Ltd, CFD Direct Ltd. https://openfoam.org
  20. Haddadi, B., Jordan, C., & Harasek, M. (2018). OpenFOAM® Basic Training, 4th edition. Institute of Chemical, Environmental & Bioscience Engineering, Technische Universität Wien.
  21. Issa, R. I. (1985). Solution of the implicitly discretized fluid flow equations by operator-splitting. Comput Phys, 62, 40-65.
  22. Kanaris, N., Grigoriadis, D., & Kassinos, S. (2011). Three dimensional flow around a circular cylinder confined in a plane channel. Physics of fluids, 23, 064106. doi:10.1063/1.3599703
  23. Kang, H. (2013). Flow Characteristics and Morphological Changes in Open-Channel Flows with Alternate Vegetation Zones. KSCE J. of Civil Engineering, 17(5), 1157-1165.
  24. Kharlamov, A. A. (2012). Modeling of transverse self-oscillations of a circular cylinder in an incompressible fluid flow in a plane channel with circulation. of Applied Mechanics and Technical Physics, 53(1), 38-42.
  25. Kozlov, I. M., Dobergo, K. V., & Gnesdilov, N. (2011). Application of RES Methods for Computation of Hydrodynamic Flows by an Example of 2D Flow Past a Circular Cylinder for Re = 5–200. International J. of Heat and Mass Transfer, 54(4), 887. http://dx.doi.org/10.1016/j.ijheatmasstransfer
  26. Kumar, A., & Ray, R. K. (2018). Numerical Simulation of Flow Around Square Cylinder with an Inlet Shear in a Closed Channel. Applications of Fluid Dynamics, Proceedings ICAFD 2016, 297-304. https://doi.org/10.1007/978-981-10-5329-0_21
  27. Lam, K., Li, J. Y., Chan, K. T., & So, R. M. C. (2003). Flow pattern and velocity field distribution of cross-flow around four cylinders in a square configuration at a low Reynolds number. Journal of Fluids and Structures, 17, 665-679.
  28. Lopez, F., & Garcia, M. (2001). Mean flow and turbulence structure of open channel flow through non-emergent vegetation, ASCE J. Hydraul. Eng., 127 (5), 392-402.
  29. Lysenko, D. A., Ertesvag, I. S., & Rian, K. E. (2012). Large-eddy simulation of the flow over a circular cylinder at Reynolds number 3900 using the OpenFOAM toolbox. Flow Turbulence Combust, 89(4), 491-518.
  30. Montelpare, D. V. S., & Ricci, R. (2016). Detached–eddy simulations of the flow over a cylinder at Re = 3900 using OpenFOAM. Comput Fluids, 136(10), 152-169.
  31. Nakagawa, S., Nitta, K., & Senda, M. (1999). An experimental study on unsteady turbulent near wake of a rectangular cylinder in channel flow. Experiments in Fluids, 27, 284-294.
  32. Norberg, C. (2001). Flow around a circular cylinder: Aspects of fluctuating lift. Fluids Struct, 15 (3-4): 459–69.
  33. Ong, M. C., Utnes, T., Holmedal, L. E., Myrhaug, D., & Pettersen, B. (2009). Numerical Simulation of Flow Around a Smooth Circular Cylinder at Very High Reynolds Numbers. Marine Structures, 22, 142. http://dx.doi.org/10.1016/j.marstruc
  34. Park, J., Kwon, K., & Choi, H. (1998). Numerical solutions of flow past a circular cylinder at Reynolds numbers up to 160. KSME International J., 12(6), 1200-1205.
  35. Patankar, S. V. (1980). Numerical Heat Transfer and Fluid Flow, Hemisphere Publishing Corp., Fluid dynamics, Taylor & Francis, ISBN: 978-0-89116-522-4.
  36. Perumal, D. A., Kumar, G. V. S., & Dass, A. K. (2012). Numerical Simulation of Viscous Flow over a Square Cylinder Using Lattice Boltzmann Method. International Scholarly Research Network ISRN Mathematical Physics, 2012, Article ID 630801, doi:10.5402/2012/630801
  37. Rajani, B. N., Gowda, R. V. P., & Ranjan, P. (2013). Numerical Simulation of Flow past a Circular Cylinder with Varying Tunnel Height to Cylinder Diameter at Re 40. International J. of Computational Engineering Research (ijceronline.com), 3(1), 188-194.
  38. Rajani, B. N., Kandasamy, A., & Majumdar, S. (2009). Numerical Simulation of Laminar Flow Past a Circular Cylinder. Applied Mathematics Modeling, 33(3), 1228-1247.
  39. Reichi, P., Hourigan, K., & Thompson, M. C. (2005). Flow past a cylinder close to a free surface. Fluid Mech., 533, 269-296.
  40. Richardson, E. V., & Panchang, G. V. (1998). Three-dimensional simulation of scour-inducing flow at bridge piers. Hydraul. Eng., 124(5), 530-540.
  41. Samet, K., Hoseini, K., Karami, H., & Mohammadi, M. (2019). Comparison Between Soft Computing Methods for Prediction of Sediment Load in Rivers: Maku Dam Case Study. J. Sci. Technol., Trans. Civ. Eng., 43, 93-103.
  42. Sarwar Abbasi, W., Islam, S. U., Faiz, L., & Rahman, H. (2018). Numerical investigation of transitions in flow states and variation in aerodynamic forces for flow around square cylinders arranged inline. Chinese Journal of Aeronautics, 31(11), 2111-2123.
  43. Sohankar, A., Norberg, C., & Davidson, L. (1998). Low-Reynolds-number flow around a square cylinder at incidence: study of blockage, onset of vortex shedding and outlet boundary condition. International Journal for Numerical Methods in Fluids, 26, 39-56.
  44. Sumer, B. M., & Fredsøe, J. (1997). Hydrodynamics Around Cylindrical Structures. Advanced Series on Ocean Engineering, Volume 12. World Scientific, Singapore.
  45. Vojoudi Mehrabani, F., Mohammadi, M., Ayyoubzadeh, S. A., Fernandes, João N., & Ferreira, Rui M. L. (2020a). Turbulent Flow Structure in a Vegetated Non-Prismatic Compound Channel, Proceedings, Journal of River Research and Applications, Wiley, 36, 1868-1878.
  46. Vojoudi Mehrabani, F., Mohammadi, M., & Ayyoubzadeh, S. A. (2020b). Flow Behavior in Non-Prismatic Convergent Compound Channel with Submerged Vegetation on Floodplains, Proceedings, Iranian Journal of Hydraulics, IHA, 15(1). (In Persian)
  47. Wang, D., Liu, Y., Li, H., & Xu, H. (2021). Secondary instability of channel-confined transition around dual-circular cylinders in tandem. International Journal of Mechanical Sciences 208, 106692, https://doi.org/10.1016/j.ijmecsci.2021.106692
  48. Wang, Y., Wang, L., J, Y., Zhang, J., Xu, M., Xiong, X., & Wang, C. (2022). Research on the force mechanism of two tandem cylinders in a stratified strong shear environment. Fluids, 34, 053308. doi:10.1063/5.0089408
  49. Wu, Y. J., Jing, H. F., Li, C. G., & Song, Y. T. (2020). Flow characteristics in open channels with aquatic rigid vegetation. Journal of Hydrodynamics, 32(6), 1100-1108.
  50. Zhang, C. W. L, & Y. M. Shen, (2010). A 3D non-linear k-ε turbulent model for prediction of flow and mass transport in channel with vegetation, Math. Modell, 34, 1021-1031.