• Title/Summary/Keyword: 심해역

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Field Observations of Spatial Structure of Hydrodynamics Including Waves and Currents in the Haeundae Coast (해운대의 파랑 및 흐름 구조의 특성파악을 위한 현장 관측실험)

  • Do, Kideok;Yoo, Jeseon;Lee, Hee Jun;Do, Jong-Dae;Jin, Jae-Youll
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.27 no.4
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    • pp.228-237
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    • 2015
  • Field observations were conducted to collect hydrodynamic and morphological data, which are needed to account for mechanisms of bathymetry changes caused by physical forcings, in Haeundae beach. In order to quantitatively describe characteristics of wave transformations and current patterns in space in winter and summer, in-situ sensors for measuring waves and current profiles were installed at three locations in the cross-shore direction and also three locations in the along-shore direction. As for the results of wave measurements, waves with main direction from the east dominate in winter while waves are incident from the S and the ESE in summer. Analysis of current data reveals that currents over the study domain are considerably influenced by a pattern of tidal motions, thereby, mainly oscillating in the direction of tidal currents, i.e., east-west directions, in both winter and summer. Currents tend to be influenced by local bathymetry in the shallow water region, with the direction changed along the depth contours and the magnitude reduced as they approach the shoreline. The results analysed from the hydrodynamic data through this study can be further combined with the morphological and bathymetry data, leading to the quantification of seasonal sediment transport rates and sand budget changes.

Variation of Harbor Response due to Construction of A New Port in Youngil Bay (영일만 신항 건설에 따른 항만 정온도의 변화)

  • Kim, Ji-Yeon;Lee, Joong-Woo;Lee, Hak-Seung;Yang, Sang-Yong
    • Journal of Navigation and Port Research
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    • v.28 no.5
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    • pp.421-428
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    • 2004
  • Introduction of wave model, considered the effect of shoaling, refraction, diffraction, partial reflection, bottom friction, breaking at the coastal waters of complex bathymetry, is a very important factor for most coastal engineering design and disaster prevention problems. As waves move from deeper waters to shallow coastal waters, the fundamental wave parameters will change and the wave energy is redistributed along wave crests due to the depth variation, the presence of islands, coastal protection structures, irregularities of the enclosing shore boundaries, and other geological features. Moreover, waves undergo severe change inside the surf zone where wave breaking occurs and in the regions where reflected waves from coastline and structural boundaries interact with the incident waves. Therefore, the application of mild-slope equation model in this field would help for understanding of wave transformation mechanism where many other models could not deal with up to now. The purpose of this study is to form a extended mild-slope equation wave model and make comparison and analysis on variation of harbor responses in the vicinities of Pohang Old Harbor and Pohang New Port, etc. due to construction of New Port in Youngil Bay. This type of trial might be a milestone for port development in macroscale, where the induced impact analysis in the existing port due to the development could be easily neglected.

Sulfate reduction and sulfur isotopic fractionation in marine sediments (해양퇴적물내에서의 황산염 환원과 황의 안정동위원소 분화)

  • 한명우
    • Journal of Environmental Science International
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    • v.2 no.1
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    • pp.43-49
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    • 1993
  • Concentrations of sulfate and 6-values of sulfate, $({\delta}^{34}SO_4_){pw}$, dissolved In pore waters were measured from the sediment cores of the two different marine environments : deep northeast Pacific (57-1) and coastal Kyunggi Bay of Yellow Sea (57-2) . Sulfate concentration in pore waters decreases with depth at both cores, reflecting sulfate reduction in the sediment columns. However, much higher gradient of pore water sulfate at 57-2 than 57-1 indicates more rapid sulfate reduction at 57-2, because of high sedimentation rate at the coastal area compared to the deep-sea. The measured 6-values, $({\delta}^{34}SO_4_){pw}$, follow extremely well the predicted trend of the Rayleigh fractionation equation. The range of 26.756 to 61.35% at the coastal core 57-2 is not so great as that of 32.4$\textperthousand$ to 97.8$\textperthousand$ at the deep-sea core 57-1. Despite greater graclient of pore water sulfate at 57-2, the 6-values become lower than those of the deep- sea core 57-1. This inverse relation between the 6-values and the gradients of pore water sulfate could be explained by the combination of the two subsequent factors : the kinetic effect by which the residual pore water sulfate becomes progressively enriched with respect to the heavy isotope of $^{34}S$ as sulfate reduction proceeds, and the intrinsic formulation effect of the Rayleigh fractionation equation in which the greater becomes the fractionation factor, the more diminished values of $({\delta}^{34}SO_4_){pw}$ are predicted.

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Nonlinear Interaction of Directional Irregular Waves (비선형 간섭을 고려한 다방향 불규칙파의 해석)

  • 홍기용
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.7 no.3
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    • pp.209-218
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    • 1995
  • Nonlinear interaction between directional wave components is theoretically analyzed in deep water. The perturbed solution for an irregular wave is derived accurate up to the third order of the wave steepness and it is shown that the wave characteristics are modulated due to the nonlinear interaction. The convergence rate of the perturbed solution depends on not only wave steepness but also wavelength ratio between wave components. The long-wave component of the perturbed solution converges rapidly. while the short-wave solution converges slowly or diverges. The short wave properties in a broad-band wave spectrum cannot accurately be obtained by the conventional wave-mode method because it fails to properly describe the modulation of short-wave frequency caused by the nonlinear interaction with much longer wave.

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Shoaling Characteristics of Boussinesq Models with Varying Nonlinearity (비선형 차수에 따른 Boussinesq 모형의 천수변형 특성)

  • Park, Seung-Min;Yoon, Jong-Tae
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.20 no.1
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    • pp.121-127
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    • 2008
  • Numerical experiments with weakly nonlinear MIKE21 BW module and fully nonlinear FUNWAVE model are performed to identify the nonlinear characteristics of Boussinesq models with varying nonlinearity. Generation of waves with varying amplitudes, nonlinear shoaling and wave propagation over submerged bar experiments showed the importance of nonlinear model in shallow water where nonlinearity becomes prominent. Fully nonlinear model showed the nonsymmetrical wave form more clearly and gave larger shoaling coefficients than those of weakly nonlinear model.

A Study on the Harbor Tranquility of Multi-directional Irregular Waves Condition (다방향 불규칙규파랑의 정온도에 관한 연구)

  • Park, Chul Ho;Shim, Kyu Tae;Shin, Bum Shick;Kim, Kyu han
    • Proceedings of the Korea Water Resources Association Conference
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    • 2015.05a
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    • pp.89-89
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    • 2015
  • 항만 및 어항 구조물을 구성하는 다양한 해안구조물은 파랑의 천수효과, 굴절, 회절, 부분반사, 해저마찰, 쇄파의 영향 등을 고려해야하며 파고 및 파향 등의 해양특성의 검토가 반드시 이루어져야 한다. 실제의 해양파가 방향스펙트럼을 갖는 다방향 불규칙파라는 것은 잘 알려져 있으며, 기존의 해안구조물의 내파설계 또는 천해역의 파랑변형 검토에 있어서도 실제 해양파에 보다 가까운 다방향 불규칙파를 이용한 수리모형실험에 의해 파랑현상을 정도 높게 재현하는 것은 매우 중요하다. 본 연구에서는 실제 해양파를 정도 높게 재현할 수 있는 다방향 불규칙파 조파장치를 사용하여 구조물 전면해역에서의 파랑스펙트럼을 재현하고, 심해에서 발달된 파랑이 천해로 진행될 때 지형에 의해 발생되는 천수변형과 구조물 주위에서 나타나는 파랑변형의 현상을 고려하여 항내로 유입되는 파랑의 분포 특성을 검토하였다. 특히, 다방향 불규칙파로 인한 항내 파고분포 특성을 검토하기 위하여 동일 파랑에 대한 규칙파 및 불규칙파랑을 조파하여 그 결과를 상호 비교하였다. 아울러, 정온수역유지를 위한 월파현상을 수리적으로 재현할 수 있는 3차원 수리모형실험 수행하여 월파현상이 항내정온도에 미치는 영향을 고찰, 해석하여 항만 시설물 계획시 안정한 정박 및 이용에 대한 가능한 정온유지여부를 검토하였다.

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Mixing Zone Analysis on Outfall Plume considering Influence of Temperature Variation (수온 변화의 영향을 고려한 방류관 플룸의 혼합역 분석)

  • Kim Ji-Yeon;Lee Joong-Woo
    • Journal of Navigation and Port Research
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    • v.28 no.10 s.96
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    • pp.947-953
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    • 2004
  • As a large scale port development in coastal waters proceeds step by step and populations in the vicinity of port are getting increased, the issue on 'how to dispose the treated municipal water and wastewater in harbor' brings peoples' concern. The submarine outfall system discharges the primary or secondary treated effluent at the coastline or in deep water, or between these two. The effluent, which has a density similar to that of fresh water, rises to the sea surface forming plume or jet, together with entraining the surrounding sea water and becomes very dilute. We intended in this paper to investigate the impact on dilution of effluent and the behavior of flume under the conditions of the seasonal and spatial temperature variations, which have not been noticeable in designing effective marine outfall system. To predict and analyze the behaviour and dilution characteristics of plume not just with the effluent temperature, but also with the seasonal variation of temperature of surround water, CORMIX( Cornell Mixing Zone Expert System)-GI have been applied. The results should be used with caution in evaluation the mixing zone characteristics of discharged water. We hope to help for the effective operation of outfall system, probable outfall design, protection of water quality, and warm water discharges from a power plant, etc.

Analysis of Numerical Experiment for Field Application of Cylindrical Slit Type Block Breakwater (실린더 슬릿형 소파블록 방파제의 실해역 적용을 위한 수치실험분석)

  • Park, Sang-Gil;Lee, Joong-Woo;Nam, Ki-Dae;Kim, Pill-Sung
    • Journal of Navigation and Port Research
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    • v.33 no.10
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    • pp.703-707
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    • 2009
  • In order to evaluate applicability of cylindrical slit type block breakwater to the field water, which was designed from the previous physical model study, it is analyzed the calmness of harbor area by the numerical model experiment. For a small fishery port in southern coast of Korea a SWAN model using the wave action balance equation was formulated. The reflection and transmission coefficients induced by the physical model test were introduced to the numerical model. The model response with cylindrical slit type breakwater was compared with the impermeable breakwater case and the possibility of water quality improvement through the water circulation by the new structure was investigated. For numerical simulation, parameters of deepwater design wave from the prediction report II for overall deepwater design wave by KORDI were used and wind parameters from the 50years return period observed for 37years(1970~2006) were adopted in the numerical model. The response of west breakwater in Mijo port applying the NE and NNE waves, which were dominant in this area, was analyzed. It was found that the transmission characteristic of designed cylindrical slit breakwater was well presented in the numerical model.

Tidal Computation of the Global Ocean using Fine-grid Numerical Model (세격자체계에 의한 전지구 해양 조석 산정)

  • 최병호;서경석
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.15 no.1
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    • pp.51-61
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    • 1997
  • A two-dimensional numerical tidal model with $1/3^\circ$ resolution has been established to investigate the distribution of semidiurnal constituents$(M_2,\;S_2,\;K_2,\;N_2)$ and diurnal constituents$(K_1,\;O_1,\;P_1,\;Q_1)$ of the global ocean. The $1/3^\circ$ numerical model has been applied to the computation of detailed tidal distributions in the marginal seas and the shelf seas. Tidal characteristics in shallow areas could be hardly resolved with the existing global chart due to the low resolution. Computed tidal charts obtained by $1/3^\circ$ numerical model have been compared with the existing global charts and the altimetry-derived tidal charts. Computed harmonic constants have also been com-pared with the pelagic tidal observations. The results obtained with fine-grid numerical model can be used to determine the time-independent sea surface topography by removing the tidal components from the altimetry-derived sea surface height.

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Determination of Design Parameters with SWAN Model at Southwest Coast (SWAN모형을 이용한 남서 도서해역에서의 설계 파라메타 추출)

  • Kim, Kang-Min;Kang, Suk-Hyung;Lee, Joong-Woo;Lee, Hoon;Kwon, So-Hyun
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.29 no.1
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    • pp.253-260
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    • 2005
  • Recently, the storms which hit Korean Peninsula are getting bigger, and the damages from the storms are wide spreaded. Thus, and approach with disaster prebention to offshore area and/or opened island area is neccessary. The existing wave design parameter was calculated with linear regular wave models inputting deep water design wave or wind sources. so it wasn't able to deal with wind-induced waves, interactions with waves, and redistribution of wave energy simultaneously. In this study, we made numerical simulation with SWAN(Simulation Waves Nearshore) Model which can consider development of waves and winds and their interference. The result from this model shows much different with those from existing model's. so the result from this study, especially in this modeling area, could be used for harbor design and coastal disaster prevention field in the future.

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