• Title/Summary/Keyword: 취송류

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Lagrangian observation and modelling of sea surface wind-induced drift(skin drift) (해양 표면취송류(skin drift)의 라그랑쥐 측류 및 모델링)

  • Lee Moonjin;Kang Yong Q.
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.3 no.2
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    • pp.11-17
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    • 2000
  • The drift and movement of oil slick in the sea are closely related to the flows at the sea surface (at 0m depth) because specific gravity of an oil is lighter than that of sea water. As an effort toward a development of realistic model for oil spill drift on the sea surface, a study on sea surface wind-induced drift (skin drift) at 4 coastal regions of Korea was carried out. In this study, skin drifts were inferred from difference between the flow at the sea surface and that in underwater (at 1.5m depth). The average speed of skin drift in our experiments was 2.9% of wind speeds and the average direction of skin drift to wind was deflected to the right by 18.6°. The results of this experiment were used in the modelling of the skin drift as a prompt response of time-variable wind. The modelled skin drift, which corresponds to observed wind, successfully reproduced the observed trajectories of sea surface flows.

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Numerical Analysis of Wind Driven Current and Mesoscale Air Flow in Coastal Region with Land Topography (육상지형을 고려한 연안해역에서의 취송류에 관한 수치해석)

  • Lee, Seong-Dae;Kim, In-Ho;Hong, Chang-Bae
    • Proceedings of the Korea Water Resources Association Conference
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    • 2006.05a
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    • pp.1925-1930
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    • 2006
  • A quasi depth-varying mathematical model for wind-generated circulation in coastal areas, expressed in terms of the depth-averaged horizontal velocity components and free surface elevation was validated and used to understand the diurnal circulation process. The wind velocity is considered as a dominant factor for driving the wind generated current. In this paper, three dimensional numerical experiments that included the land topography were used to investigate the mesoscale air flow over the coastal regions. The surface temperature of the inland was determined through the surface heat budget consideration with inclusion of a layer of vegetation. A series of numerical experiments were then carried out to investigate the diurnal response of the air flow and wind-generated circulation to various types of surface inhomogeneities.

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An Effect of Drift Current on Generation Stage of Wind Waves (風波發생에 있어서 吹送流의 影響)

  • Choi, In june
    • 한국해양학회지
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    • v.19 no.2
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    • pp.195-199
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    • 1984
  • Effect of drift current on the first stage of wave generation by wind is studied theoretically. The viewpoint is similar to the one described by Phillips (1957) except that drift current is considered. It is found that inclusion of the effect of the drift current modifies significantly the results obtained by Phillips, particularly the resonance condition and wave spectrum.

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Numerical experiments for the changes of currents by reclamation of land in Kwangyang Bay (매립으로 인한 광양만의 유동변화 수치실험)

  • 추효상
    • Journal of Environmental Science International
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    • v.11 no.7
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    • pp.637-650
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    • 2002
  • This study presents an investigation of the changes of the currents in Kwangyang Bay due to the construction of harbor, reclamation and coastal developments. Currents were simulated by the numerical experiments with a diagnostic multi-level model and using the seasonal oceanographic data of temperature, salinity and ocean current. The values of kinetic and potential energies for the currents were calculated in cases of three topographical changes; before coastal developments, the existing state and after completion of the development project in Kwangyang Bay. The changes of currents due to the coastal developments are as follow; Kinetic energies of tide induced residual currents and wind driven currents decreased by 35~40 percent and 5 percent respectively, however those of density currents increased by 10 percent since the decrease of the coastal areas. Kinetic energy of residual currents including tide induced residual currents, density currents and wind driven currents reduced by 10 percent compared with before the coastal developments. Decrease of current velocity was greatest in summer. Therefore, in summer it was assumed that the Kwangyang Bay is more easily polluted by stratification and decrease of residual current than before the coastal developments carried out.

A study of Robust Diagnostic Model of residual current in coastal sea (연안해역에서 잔차류의 Robust진단 model에 관한 연구)

  • 신문섭;홍성근
    • Proceedings of the Korea Water Resources Association Conference
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    • 1996.05a
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    • pp.683-688
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    • 1996
  • The purpose of this study is to find seasonal variation of the water circulation in the Chenbuk coastal sea region. Chenbuk coastal sea is investigated with use of a robust diagnostic numerical model. Water circulations in four seasons are calculated diagnostically from the observed water temperature and salinity data and wind data from Kunsan mereorologcal station.

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Comparison of Turbulence Models in Homogeneous Channel Flows (등밀도 수로흐름에서 의 난류모형 비교)

  • 이종찬;최병호
    • 한국해양학회지
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    • v.30 no.1
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    • pp.13-26
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    • 1995
  • In this paper three turbulence models including two-equation model by Blumberg and Mellor (1987), one-equation model with mixing length formula of Blackadar's (1962), and zero-equation model of Prandtl's (1925) were compared in homogeneous, unstratified channel flows. Steady flows which a steep-sided trapezoidal trench with uniform discharge, tidal flow and steady wind-driven flow in finite channels are considered in detail. Steady flows in a trench and tidal flows in a finite channel were reproduced fairly accurately and there was virtually no difference among results of three turbulence models. However, In case of steady wind-driven flow only two-equation model reproduced the important features of experimental data. the other two models underestimated the surface velocity. In tidal and wind-driven flows with negligibly small adjective and diffusive effects, the two-equation model gives rise to parabolic profile of eddy viscosity with maximum at the mid0depth, and the one and zero equation model based on Blackadar formula linear profile with maximum at the surface.

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Numerical Simulation of Spilled Oil Dispersion in Taean Coastal Zone (태안유류유출사고의 유출유 초기확산 수치모의)

  • Jung, Tae-Sung
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.12 no.4
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    • pp.264-272
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    • 2009
  • Due to an oil spill accident occurred in Taean coastal zone wide range of coastal waters were polluted. Inaccurate prediction of spilled oil trajectory is known as a cause that has increased the pollution damage in the beginning stage. In this study, a numerical modeling of spilled oil dispersion has been conducted to know which physical factors caused the severe and wide pollution. Especially the simulation is focused on how to model hydrodynamic circulation accurately. The simulation results showed that the hydrodynamic flow is very important in predicting oil fate, specially, in the short-term dispersion of spilled oil.

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Numerical Computation of Near Shore Surface Flow due to Tide and Wind (조석 및 바람에 의한 실해역 표층유동의 계산)

  • J.H. Rho;B.S. Yoon
    • Journal of the Society of Naval Architects of Korea
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    • v.32 no.2
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    • pp.22-31
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    • 1995
  • In this paper, a 3-dimensional multi-layer current simulation program is allied to real shore area near Inchon harbor with highly irregular bottom and continental geometry. The effects of bottom topography on vertical structures of the ocean tidal current is investigated through comparing the calculated results by 2-dimensional depth averaged approach and the present method. Wind induced current, which may be more dominant factor in Predicting oil spill behavior, is also simulated by the present computation algorithm. Comparison shows quite large differences not only in vertical distribution of the current but also in the direction of the surface current.

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