• Title/Summary/Keyword: Tandem Oil Fence

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Analysis of Effectiveness of Tandem Oil Fences (이중유벽의 유효성에 관한 해석)

  • Han Dong Gi;Lee Choung Mook
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.4 no.1
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    • pp.38-46
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    • 2001
  • To assess the oil-containment effectiveness of tandem oil fences placed in currents, the movement of oil droplets in the fore and aft region of the fences is investigated by experimental and numerical methods. The effect of the flexibility of the fence skirt of single fence on the fence effectiveness is also investigated. Laboratory experiment is conducted to trace the path of a spherical solid particle of equivalent density to an oil droplet which was released in a uniform stream ahead of a model oil fence. Depending upon the releasing position and the flow condition there, it was observed that the particle floated up to the free surface, collided with the fence, or escaped below the fence. By analyzing the droplet trajectories, a numerical method is developed to predict the region ahead of the fore fence where an oil droplet initiating its motion eventually escapes beneath the fence. The effect of the relative sizes of the drafts of the fore and aft fences, the fence separation, and the bottom depth of the sea bed on the effectiveness of tandem fences is investigated using the numerically obtained trajectories of oil droplets.

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Analysis of Containment Capability of Oil Fence in Currents and Waves (조류와 파랑중에서의 유벽의 보유성능 해석)

  • Lee Choung Mook;Kang Kwan Hyoung
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.1 no.1
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    • pp.29-38
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    • 1998
  • This paper summarizes the results of the investigations performed by the authors for a number of years on the performance of oil fences in currents and waves. The leakage inception velocity of currents, the wave-exciting motion of fences and the deformation of the fence skirt due to currents are investigated. The results show that improvement of the fence performance is necessary in order to utilize the oil fences as an effective containing device for spilt oils in ocean environments. As an approach toward improving the fence effectiveness, tandem fences in currents are investigated. It was found that an appropriate deployment of tandem fences of identical configuration could significantly improve the oil containment capability.

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Effect of tip configuration of an oil fence on wake structure behind the fence (오일펜스의 tip 형상이 후류유동에 미치는 영향에 관한 연구)

  • Koh, Min-Seok;Lee, Sang-Joon;Lee, Choung-Mook;Chung, Sang-Kook
    • Proceedings of the KSME Conference
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    • 2001.06e
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    • pp.772-776
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    • 2001
  • The flow structures of turbulent shear layer behind oil fences with different tip configurations were investigated experimentally using flow visualization and PIV velocity field measurement. An oil fence was installed in a circulating water channel and the flow structure around the fence tip was mainly analyzed in this experiment. The four tip configurations tested in this experiment are knife edge; semi-circle edge, circular edge and rectangular edge. The 300 instantaneous velocity fields were measured using the single-frame PIV system and they were ensemble averaged to give the mean velocity field and spatial distribution of turbulent statistics. Free stream velocity was fixed at 10ms/sec and the corresponding Reynolds number based on the fence height was Re=4000. As a result, for the oil fence with rectangular edge, the streamwise velocity component was decreased. On the other hand it was increased for the oil fence with circular edge. For all four fences tested in this study, general flow pattern of the lower shear layer is analogous but the upper layer shows difference depending on the tip configurations. The oil fence with circular edge has more diffusive upper shear layer than that of the others. The shear layer of the oil fence with rectangular edge has relatively thin thickness. The oil fence with circular edge was found to be proper shape for tandem fence.

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On Oil-Water Interface of Oil Layer Contained in Tandem Oil Fences (이중유벽 사이에 가두어진 기름층의 거동특성)

  • Doh D.H.;Hyun B.S.;Choi S.H.;Hong S.H.
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.3 no.1
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    • pp.25-34
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    • 2000
  • A panoramic-PIV technique is employed to characterize the travelling tip vortices and the profile of oil-water Interface in the tandem fence arrangement. Instantaneous as well as time-averaged velocity profiles of the water layer close to the interface were obtained to evaluate the possibility of measuring the shear stress distribution on oil-water interface. It was proven that the present technique could provide some qualify data precise enough to resolve detailed flow structures inside a shear layer formed on oil-water interface provided it is nearly stationary.

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Behavior of Oil-Water Interface between Tandem Fences (이중 유벽 사이의 기름과 물의 계면의 거동)

  • Kang Kwan Hyoung;Lee Choung Mook
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.2 no.2
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    • pp.70-77
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    • 1999
  • The disturbance of oil-water interface confined between tandem fences caused by a sequence of traveling vortices below the interface is investigated. The traveling vortices are assumed to be those detached from the tip of the fore fence. The potential flow is assumed and the density interface is replaced as a sheet of vortex. The shape of the interface is predicted by tracing a finite number of marker particles placed at the interface. The velocity of the marker particles is determined by the Biot-Savart integral along the vortex sheet plus the contribution from the traveling point vortices. The rate of change of vortex-sheet strength is predicted by using an evolution equation for vorticity. The calculated results obtained for various conditions demonstrate that the large amplitude of interfacial wave following the moving vortek can be generated by the vortices.

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