• Title/Summary/Keyword: Self Burial

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An Experimental Study for Analysis of the Self-Burial of Pipelines with Spoilers in Current

  • Kang, Min Joon;Lee, Seung Jae;Hwang, Jae Hyuk;Jo, Hyo Jae
    • Journal of Advanced Research in Ocean Engineering
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    • v.2 no.1
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    • pp.22-27
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    • 2016
  • This experimental study deals with the mechanism of spoilers that cause scouring around pipelines. The design methodology was applied to spoilers for accelerating pipelines that undergo self-burial into the sand-bed and evaluated using approaching experimental analysis. The experimental study was conducted to investigate the self-burial ability of submarine pipelines with two types of sand-bed models: silt and sand. Spoilers of different heights were attached to the top of the pipeline for each experiment case. The relationship between the relative scour depth and spoiler height was evaluated by applying different flow velocities and sand diameters and comparative analysis was performed with values obtained from similarity experiments and theory. The experimental study will be useful in establishing a database for the design of spoilers.

Self-Burial Structure of the Pipeline with a Spoiler on Seabed (해저지반에 설치된 스포일러 부착형 파이프라인의 자가매설 기능분석)

  • Lee, Woo-Dong;Hur, Dong-Soo;Kim, Han-Sol;Jo, Hyo-Jae
    • Journal of Ocean Engineering and Technology
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    • v.30 no.4
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    • pp.310-319
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    • 2016
  • If a spoiler was attached to the pipeline investigated in a previous study, a strong flow and vortex at the lower part caused scouring and thus an asymmetric pressure distribution, which assisted in the analysis of the self-burial structure where a down force was applied to the pipe. However, only the fluid-pipe interaction was considered, excluding the medium (seabed), when practically burying the pipeline. Thus, this study applied a numerical model (LES-WASS-2D) to directly analyze the non-linear interactions among the fluid, pipe, and seabed in order to perform numerical simulations of a pipeline with a spoiler installed on the seabed. This allowed the self-burial mechanism of a pipeline with a spoiler to be analyzed in the same context as the previous study that considered only the fluid-pipe interaction. However, when a pipeline was installed on the seabed, a strong flow and vortex were found at the front of the bottom, and a spoiler accelerated the fluid resistances. This hydraulic phenomenon will reinforce the scouring and down force on the pipeline. In the general consideration of the numerical analysis results by the specifications and arrangements of the spoiler, a pipeline with a spoiler was found to be the most effective for the self-burial function.

Scour around spherical bodies due to long-crested and short-crested nonlinear random waves

  • Myrhaug, Dag;Ong, Muk Chen
    • Ocean Systems Engineering
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    • v.2 no.4
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    • pp.257-269
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    • 2012
  • This paper provides a practical stochastic method by which the maximum equilibrium scour depth around spherical bodies exposed to long-crested (2D) and short-crested (3D) nonlinear random waves can be derived. The approach is based on assuming the waves to be a stationary narrow-band random process, adopting the Forristall (2000) wave crest height distribution representing both 2D and 3D nonlinear random waves, and using the regular wave formulas for scour and self-burial depths by Truelsen et al. (2005). An example calculation is provided.

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;Hur, Dong Soo;Kim, Han Sol;Jo, Hyo Jae
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.28 no.3
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    • pp.146-159
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    • 2016
  • 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.