Journal of Korean Society of Coastal and Ocean Engineers (한국해안·해양공학회논문집)

Korean Society of Coastal and Ocean Engineers (한국해안·해양공학회)
권호 표지
DOI QR코드

DOI QR Code

Numerical Analysis on Self-Burial Mechanism of Submarine Pipeline with Spoiler under Steady Flow

정상흐름 하에서 스포일러 부착형 해저파이프라인의 자가매설 기구에 관한 수치해석

  • Lee, Woo Dong (Institute of Marine Industry, Gyeongsang National University) ;
  • Hur, Dong Soo (Department of Ocean Civil Engineering, Gyeongsang National University) ;
  • Kim, Han Sol (Department of Coastal Management, Geosystem Research Corporation) ;
  • Jo, Hyo Jae (Naval Architecture and Ocean Systems Engineering, Korea Marine and Ocean University)
  • 이우동 (경상대학교 해양산업연구소) ;
  • 허동수 (경상대학교 해양토목공학과) ;
  • 김한솔 ((주)지오시스템리서치 연안관리부) ;
  • 조효제 (한국해양대학교 조선해양시스템공학부)
  • Received : 2016.04.22
  • Accepted : 2016.06.15
  • Published : 2016.06.30
Download PDF
⟨ Previous Next ⟩

Abstract

This study used Navier-Stokes Solver(LES-WASS-2D) for analyzing hydrodynamic characteristics with high order in order to analyze self-burial mechanism of pipeline with spoiler under steady flow. For the validity and effectiveness of numerical model used, it was compared and analyzed with the experiment to show flow characteristics around the pipeline with and without the spoiler. And the hydraulic(flow, vortex, and pressure) and force characteristics were numerically analyzed around the pipeline according to the incident velocity, and shape and arrangement of spoiler. Primarily, if the spoiler is attached to the pipeline, the projected area is increased resulting in higher flow velocity toward the back and strong vortex caused by wake stream in the back. Secondly, the spoiler causes vertically asymmetric flow and vorticity fields and thus asymmetric pressure field. It increases the asymmetry of force on the pipe and thus develops large downward fluid force. Both of them are the causes of selfburying of the pipeline with spoiler.

본 연구에서는 정상흐름 하에서 스포일러가 부착된 해저파이프라인의 자가매설 기구를 분석하기 위하여 유체역학적 특성을 고정도로 해석할 수 있는 Navier-Stokes Solver(LES-WASS-2D)를 이용하였다. 본 논문에서 적용하는 수치모형의 타당성 및 유효성을 확보하기 위하여 기존의 스포일러 유무에 따른 파이프라인 주변의 흐름특성을 나타낸 수리모형실험결과와 비교 분석하였다. 그리고 입사유속, 스포일러의 제원 및 배치에 따른 파이프라인 주변의 수리특성(유동, 와동, 압력)과 작용력 특성을 수치적으로 분석하였다. 그 결과 1차적으로 해저파이프에 스포일러가 부착된 경우에 투영면적이 증가함으로 인하여 배후로 빠져나가는 유속이 커지고, 동시에 배후에서 발생하는 후류에 기인한 강한 와동이 발생한다. 그리고 2차적으로는 스포일러의 영향으로 상하 비대칭적인 유동 및 와동장이 발생하고, 이로 인해 비대칭적인 압력장이 형성된다. 이것은 파이프에 작용하는 힘의 비대칭성을 증가시켜 하향의 유체력을 크게 발달시킨다. 이와 같은 두 가지의 큰 원인으로 인하여 스포일러 부착형 해저파이프라인이 자가매설 되는 것으로 이해된다.

Keywords

References

  1. Bakhtiary, A.D. and Zeinali, M. (2008). Numerical simulation of hydrodynamic forces on submarine pipeline with a spoiler. International Conference on Coasts, Ports and Marine Structures(ICOPMAS), Ports and Marine Organization, 8, 1-12.
  2. Barendse, C.A.M. (1988). Hydrodynamic forces on a near-bed offshore pipeline with spoiler during the selfburying process. TU Delft, Faculty of Civil Engineering.
  3. Brackbill, J.U., Kothe, D.B. and Zemach, C. (1992). A continuum model for modeling surface tension. Journal of Computational Physics, 100, 335-354. https://doi.org/10.1016/0021-9991(92)90240-Y
  4. Cheng, L. and Chew, L. (2003). Modelling of flow around a nearbed pipeline with a spoiler. Ocean Engineering, 30, 1595-1611. https://doi.org/10.1016/S0029-8018(02)00148-8
  5. Chiew, Y. (1993). Effect of spoilers on wave induced scour at submarine pipelines. J. Waterway, Port, Coastal, Ocean Engineering, 417, 417-428.
  6. Ergun, S. (1952). Fluid flow through packed columns. Chemical Engineering Progress, 48(2), 89-94.
  7. Germano, M., Piomelli, U., Moin, P. and Cabot, W.H. (1991). A dynamic subgrid-scale eddy viscosity model. Physics of Fluids, 3, 1760-1765. https://doi.org/10.1063/1.857955
  8. Han, Y. (2012). Study on the submarine pipeline with flexible spoilers. Key Engineering Materials, 501, 431-435. https://doi.org/10.4028/www.scientific.net/KEM.501.431
  9. Hur, D.S., Lee, K.H. and Choi, D.S. (2011). Effect of the slope gradient of submerged breakwaters on wave energy dissipation. Engineering Applications of Computational Fluid Mechanics, 5, 83-98. https://doi.org/10.1080/19942060.2011.11015354
  10. Hur, D.S., Lee, W.D. and Bae, K.S. (2008). On reasonable boundary condition for inclined seabed/structure in case of the numerical model with quadrilateral mesh system. Journal of Korean Society of Civil Engineers, KSCE, 28(5B), 591-594 (in Korean).
  11. Hulsbergen, C.H., (1984). Stimulated self-burial of submarine pipelines. Proceedings of the 16th Offshore Technology Conference, OTC 4667, 171-177.
  12. Hulsbergen, C.H. and Bijker, H., (1989). Effect of spoilers submarine pipeline stability. Proceedings of the 21st Offshore Technology Conference, OTC 6154, 337-350.
  13. Lilly, D.K. (1992). A proposed modification of the Germano subgrid-scale closure method. Physics of Fluids, 4, 633-635. https://doi.org/10.1063/1.858280
  14. Liu, S. and Masliyah, J.H. (1999). Non-linear flows in porous media. Journal of Non-Newtonian Fluid Mechanics, 86, 229-252. https://doi.org/10.1016/S0377-0257(98)00210-9
  15. Oner, A.A. (2010). The flow around a pipeline with a spoiler. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering, 224(1), 109-121. https://doi.org/10.1243/09544062JMES1699
  16. Sakakiyama, T. and Kajima, R. (1992). Numerical simulation of nonlinear wave interacting with permeable breakwater. Proceedings of 23rd International Conference on Coastal Engineering, ASCE, 1517-1530.
  17. Smagorinsky, J. (1963). General circulation experiments with the primitive equation. Monthly Weather Review, 91, 99-164. https://doi.org/10.1175/1520-0493(1963)091<0099:GCEWTP>2.3.CO;2
  18. Yang, L., Shi, B., Guo, Y. and Wen, X. (2012). "Calculation and experiment on scour depth for submarine pipeline with a spoiler." Ocean Engineering, 55, 191-198. https://doi.org/10.1016/j.oceaneng.2012.07.031
  19. Zhao, J. and Wang, X. (2009). CFD numerical simulation of the submarine pipeline with a spoiler. Journal of Offshore Mechanics and Arctic Engineering, 131, 031601. https://doi.org/10.1115/1.3124127
  20. Zhu, H., Qi, X., Lin, P. and Yang, Y. (2013). Numerical simulation of flow around a submarine pipe with a spoiler and currentinduced scour beneath the pipe. Applied Ocean Research, 41, 87-100. https://doi.org/10.1016/j.apor.2013.03.005

Cited by

  1. Numerical Simulation of Local Scour in Front of Impermeable Submerged Breakwater Using 2-D Coupled Hydro-morphodynamic Model vol.30, pp.6, 2016, https://doi.org/10.5574/KSOE.2016.30.6.484
  2. Self-Burial Structure of the Pipeline with a Spoiler on Seabed vol.30, pp.4, 2016, https://doi.org/10.5574/KSOE.2016.30.4.310