Fig. 4 Current lines in the horizontal level in: a 0.70 and b 14 cm from the streambed in tandem pies

트윈 말뚝 주위의 유동장 3D 수치 시뮬레이션

Amini, A; Parto, AA
Amini, A (reprint author), AREEO, Kurdistan Agr & Nat Resources Res & Educ Ctr, Sanandaj, Iran.
, 2017; 65 (6): 1243

Abstract

이 연구에서는, 파일 그룹 주위의 흐름 패턴과 국소적 스크루 메커니즘을 식별하기 위해, 플로우 필드를 FLOW-3D 소프트웨어를 사용해 시뮬레이션했다. 편평한 침대 채널에 나란히 배열되어 있는 한 쌍의 말뚝이 조사되었다. Navier-Stokes 방정식을 확립하기 위해 RNGk-epsilon 난류 모델을 사용하였고 실험 데이터를 사용하여 결과를 검증하였다. FLOW-3D 기능의 경우, 소프트웨어가 파일 그룹 간의 예상 상호작용을 적절히 시뮬레이션할 수 있는 것으로 확인되었다. 플로우 필드 시뮬레이션 결과는 레이놀즈 숫자와 말뚝 간격이 vortices 형성에 가장 큰 영향을 미치는 변수라는 것을 보여주었다. 탠덤 더미 주변의 흐름과 웨이크 바이크 주변의 하향 흐름은 측면 배치와 단일 더미에 비해 더 강렬하고 복잡했다.

In this study to identify the flow pattern and local scour mechanism around pile groups, the flow field was simulated using FLOW-3D software. A pair of pile on a flat-bed channel with side by side and tandem arrangements was investigated. To establish Navier–Stokes equations, the RNGk-e turbulence model was used and the results were verified using experimental data. In case of FLOW-3D capability, it was found that the software was able to properly simulate the expected interaction between the pile groups. The results of flow field simulation showed that Reynolds number and the pile spacing are the most influential variables in forming vortices. The flow around tandem pile and the downward flow around wake vortices were more intense and complicate in comparison with side by side arrangements and single pile.

Keywords : Bridge, Sediment, Flow pattern, Pile group, Local scour

Fig. 1 General view of the channel and measured points a side by side b tandem arrangement
Fig. 1 General view of the channel and measured points a side by side b tandem arrangement
Fig. 2 Meshing around the two side by side piles: a plan and b side view
Fig. 2 Meshing around the two side by side piles: a plan and b side view
Fig. 3 Meshing around the two tandem piles: a plan and b side view
Fig. 3 Meshing around the two tandem piles: a plan and b side view
Fig. 4 Current lines in the horizontal level in: a 0.70 and b 14 cm from the streambed in tandem pies
Fig. 4 Current lines in the horizontal level in: a 0.70 and b 14 cm from the streambed in tandem pies
Fig. 5 Current lines in the horizontal level in: a 0.70 cm, and b 14 cm from the streambed in side by side piles
Fig. 5 Current lines in the horizontal level in: a 0.70 cm, and b 14 cm from the streambed in side by side piles
Fig. 6 Comparing iso-velocity line in longitudinal direction (u): a observed in 0.7 cm; b observed in 14 cm; c simulated in 0.7 cm and d simulated in 14 cm
Fig. 6 Comparing iso-velocity line in longitudinal direction (u): a observed in 0.7 cm; b observed in 14 cm; c simulated in 0.7 cm and d simulated in 14 cm
Fig. 7 Comparing iso-velocity line in latitudinal direction (v): a observed in 0.7 cm; b observed in 14 cm; c simulated in 0.7 cm and d simulated in 14 cm
Fig. 7 Comparing iso-velocity line in latitudinal direction (v): a observed in 0.7 cm; b observed in 14 cm; c simulated in 0.7 cm and d simulated in 14 cm
Fig. 8 3D velocity profiles in x–z plane in the center of the pile (Y = 0): a x = - 1.65D; b x = - 6.59D; c x = 0.69D; d x = 1.32D; e x = 3.69D and f x = 7.60D
Fig. 8 3D velocity profiles in x–z plane in the center of the pile (Y = 0): a x = – 1.65D; b x = – 6.59D; c x = 0.69D; d x = 1.32D; e x = 3.69D and f x = 7.60D
Fig. 9 Comparison of simulated and observed velocity in x–y plane in center of piles
Fig. 9 Comparison of simulated and observed velocity in x–y plane in center of piles

References

  • Akilli AA, Karakus C (2004) Flow characteristics of circular cylinders arranged side-by- side in shallow water. Flow Meas Instrum 15(4):187–189
  • Amini A, Mohammad TM (2017) Local scour prediction in complex pier. Mar Georesour Geotechnol 35(6):857–864
  • Amini A, Melville B, Thamer M, Halim G (2012) Clearwater local scour around pile groups in shallow-water flow. J Hydraul Eng (ASCE) 138(2):177–185
  • Amini A, Mohd TA, Ghazali H, Bujang H, Azlan A (2011) A local scour prediction method for pile cap in complex piers. ICE-water Manag. 164(2):73–80
  • Aslani A (2008) Experimental evaluation of flow pattern around double piles. MSc thesis, Sharif University, Tehran
  • Gu ZF, Sun TF (1999) On interference between two circular cylinders in staged arrangement at high sub-critical Reynolds numbers. J Wind Eng Ind Aerodyn 80:287–309
  • Hang-Wook P, Hyun P, Yang-Ki C (2014) Evaluation of the applicability of pier local scour formulae using laboratory and field data. Mar Georesour Geotechnol. https://doi.org/10.1080/ 1064119X.2014.954658
  • Hannah CR (1978) Scour at pile groups. Research Rep. No. 78-3, Civil Engineering, Univ. of Canterbury, Christchurch
  • Hosseini R, Amini A (2015) Scour depth estimation methods around pile groups. J Civ Eng KSCE 19(7):2144–2156
  • Lanca R, Fael C, Maia R, Peˆgo J, Cardoso A (2013) Clear-water scour at pile groups. J Hydraul Eng. ttps://doi.org/10.1061/ (ASCE)HY.1943-7900.0000770
  • Mohamed HI (2013) Numerical simulation of flow and local scour at two submerged-emergent tandem cylindrical piers. J Eng Sci 41(1):1–19
  • Palau-Salvador G, Stoesser T, Rodi W (2008) LES of the flow around two cylinders in tandem. J Fluids Struct 24(8):1304–1312
  • Papaionannou GV, Yuea DKP, Triantafylloua MS, Karniadakis GE (2008) On the effect of spacing on the vortex-induced vibrations of tandem cylinders. J Fluids Struct 24:833–854
  • Price SJ, Paidoussis MP (1989) The flow induced response of a single flexible cylinder in an in-line array of rigid cylinder. J Fluid Struct 3:61–82
  • Raudkivi AJ (1998) Loose boundary hydraulics. A. A. Balkema, Rotterdam, pp 8–28. https://doi.org/10.1080/02508069608686502
  • Salim MS, Cheah SC (2009) Wall y ? strategy for dealing with wallbounded turbulent flows. In: Proceedings of the international multiconference of engineers and computer scientists, vol II, IMECS, Hong Kong
  • Shin JH, Park HI (2010) Neural network formula for local scour at piers using field data. Mar Georesour Geotechnol 28(1):37–48
  • Sicilian JM, Hirt CW, Harper RP (1987) FLOW-3D. Computational modeling power for scientists and engineers. Report FSI-87-00-Flow Science. Los Alamos, NM
  • Solaimani N, Amini A, Banejad H, Taheri P (2017) The effect of pile spacing and arrangement on bed formation and scour hole dimensions in pile groups. Int J River Basin Manag 15(2):219–225
  • Sumer BM, Fredsøe J (2002) The mechanics of scour in the marine environment. World Scientific, Farrer Road, Singapore
  • Sumer B, Chua L, Cheng N, Fredsøe J (2003) Influence of turbulence on bed load sediment transport. J Hydraul Eng. https://doi.org/ 10.1061/(ASCE)0733-9429(2003)129:8(585)
  • Sun TF, Gu ZF, He DX, Zhang LL (1992) Fluctuating pressure on two circular cylinder at high Reynolds number. J Wind Eng Ind Aero. 42:577–588
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