Numerical Simulation of Two-Phase Transient Flow Around Two Side-By-Side Circular Cylinders and Select Appropriate Turbulence Model Based on Vortex Shedding Frequency

Document Type : Research Paper

Authors

• Abolfazl Aslani Kordkandi ¹
• Meysam Bayati ²
• Freydon Vafai ³
• Aref Farhangmehr ²

¹ Department of Engineering, Payame Noor University (PNU), P.O. Box 19395‑4697, Tehran, Iran.

² Former M.Sc. Student of Marine Structures, K.N. Toosi University of Technology, Tehran, ‎Iran.

³ Associate Prof. of Marine Structures, Department of Civil Engineering, K.N. Toosi University of Technology, Tehran, Iran.

10.30495/wej.2023.23442.2215

Abstract

Abstract
Introduction: Nowadays, scouring is one of the important issues in river engineering as well as coastal ‎engineering. Based on the results of the investigations, the destruction of most of the bridges ‎built in the rivers is due to scouring around piers. For this reason, it has been the subject of ‎many researches conducted in recent years‏.‏ ‎ Investigation of the flow pattern around the piers ‎gives a more accurate understanding and vision for scouring prediction.‎
Methods: The flow pattern around two side-by-side circular cylinder with various gaps are investigated numerically in current study. The numerical calculations are carried out on quadrilateral mesh which is finer close to the cylinders vicinity in order to provide better description of boundary layer and gradually become coarser further places. In term of simulation of the free surface effect, the volume of fluid (VOF) method used. In this simulation based on the frequency of vortex shedding and Strouhal number. After selecting appropriate turbulence model (RNG k - ε) the value of velocity, turbulence and bed shear stress reported.
Findings: The results show that by reducing the gap between two cylinders, the velocity in middle of cylinders increases and the maximum velocity observed in G/D=1.5 while for smaller gaps (G/D<1.5) the velocity decreases due to blockage. In case of two side-by-side cylinders turbulence intensity in the middle of channel is higher than in bed which represent the significant impact of vortices. However, in case of single cylinder turbulence intensity in the bed of channel is higher than those of in middle which represent the significant impact of bed on turbulence intensity.

Keywords

• Numerical Simulation of two
• phase transient flow around two side
• by
• side circular cylinders

20.1001.1.20086377.1401.15.55.1.8

---

References

1.       Aslani-Kordkandi A. 2009. Experimental Investigation of Flow Pattern around Pile Groups (two piles). Master's thesis, Sharif University of Technology, Iran.

2.       Safaripour N, vaghefi M, mahmoudi A. 2018. Investigation of the effect of counter clockwise ‎submerged vanes on reduced scour around single bridge pier in the sharp bend. Journal ‎of Irrigation and Water Engineering. 8(2): 19-28. ‎

3.       Ghodsi H, Khanjani MJ. 2018. Experimental Investigation of Local Scour around Complex ‎Bridge Pier. Journal of Irrigation and Water Engineering. 8(3): 35-47. ‎

4.       ‎Ataie-Ashtiani B, Aslani-Kordkandi A. 2012. Flow field ‎around side-by-side piers with and without a scour hole. ‎European Journal of Mechanics-B/Fluids. 36: 152-166.‎

5.       ‎Ataie-Ashtiani B, Aslani-Kordkandi A. 2013. Flow field ‎around single and tandem piers. Flow, Turbulence and ‎Combustion. 90(3): 471-490.‎

6.       ‎Ahmed F, Rajaratnam N. 1998. Flow around bridge ‎piers. Journal of Hydraulic Engineering. 124(3): 288-‎‎300.‎

7.       ‎Ahmed F, Rajaratnam N. 2000. Observations on flow ‎around bridge abutment. Journal of Engineering ‎Mechanics. 126(1): 51-59. ‎

8.       ‎Akilli H, Akar A, Karakus C. 2004. Flow characteristics ‎of circular cylinders arranged side-by-side in shallow ‎water. Flow Measurement and Instrumentation. 15(4): ‎‎187-197‎

9.       ‎Barbhuiya A. K, Dey S. 2004. Measurement of ‎turbulent flow field at a vertical semicircular cylinder ‎attached to the sidewall of a rectangular channel. Flow ‎Measurement and Instrumentation. 15(2): 87-96.‎

10.    ‎Behrouzi, Z., Hamidifar, H., Zomorodian, M. 2021. ‎Numerical simulation of flow velocity around single and ‎twin bridge piers with different arrangements using the ‎Fluent model. Amirkabir Journal of Civil Engineering, ‎‎53(9)‎‏:‏‎ 1-15. ‎

11.    ‎Chang, C.K., Lu, J.Y., Lu, S. Y., Wang, Z. X., Shih, D. S. ‎‎2020. Experimental and Numerical Investigations of‏ ‏Turbulent Open Channel Flow over a Rough Scour Hole ‎Downstream of a Groundsill. Water, 12, 1488‎‏.‏‎ ‎

12.    ‎Dargahi B. 1989. The turbulent flow field around a ‎circular cylinder. Experiments in Fluids. 8(1-2): 1-12.‎

13.    ‎Hamidi,‎‏ ‏A., Siadatmousavi S. M. 2018. Numerical ‎simulation of scour and flow field for different ‎arrangements of two piers using SSIIM model. Ain Shams ‎Engineering Journal 9‎‏:‏‎ 2415‎‏-‏‎2426‎‏.‏

14.    ‎Hannah C. R. 1978. Scour at pile groups. Research ‎Report, University of Canterbury, New Zealand.‎

15.    ‎Melville B. W, Raudkivi A. J. 1977. Flow ‎characteristics in local scour at bridge piers. Journal of ‎Hydraulic Research. 15(4): 373-380.‎

16.    ‎Millero F. J., Feistel R, Wright D. J.,‎‏ ‏McDougall T. J. ‎‎2008. The composition of Standard Seawater and the ‎definition of the Reference-Composition Salinity Scale. ‎Deep Sea Research. 55(1): 50-72.‎

17.    ‎Sarker M. A. 1998. Flow measurement around scoured bridge piers using Acoustic-Doppler Velocimeter (ADV). Flow Measurement and Instrumentation. 9(4): 217-227.

18.    ‎Sumer B. M, Fredsøe J. 2002. The mechanics of scour ‎in the marine environment. World Scientific Publishing ‎Co Pte Ltd.‎

19.    ‎Tarek M, Imran J, Chaudhry H. 2004. Numerical ‎modeling of threedimensional‏ ‏flow field around circular ‎piers. Journal of Hydraulic Engineering. 130(2): 91-100.‎

20.    ‎Zdravkovich M. M. 1987. The effects of interference ‎between circular cylinders in cross flow. Journal of ‎Fluids and Structures. 1: 239-261.‎