• Title/Summary/Keyword: wave hindcast

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Shallow-water Design Waves at Gangreung Beach through the Analysis of Long-term Measured Wave Data and Numerical Simulation Using Deepwater Wave Conditions (장기 파랑관측자료 분석 및 천해파 수치실험에 의한 강릉 해역의 천해설계파)

  • Jeong, Weon Mu;Jun, Ki Cheon;Kim, Gunwoo;Oh, Sang-Ho;Ryu, Kyong-Ho
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.24 no.5
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    • pp.343-351
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    • 2012
  • In this study, shallow-water design waves are calculated for the return period of 10, 20, 30, and 50 years, based on the extreme value analysis of the wave measurement data at Gangneung beach. These values are compared with the results of SWAN simulation with the boundary condition of the deep-water design waves of the corresponding return periods at the Gangneung sea area provided by the Fisheries Agency (FA, 1988) and Korea Ocean Research & Development Institute (KORDI, 2005). It is found that the shallow-water wave heights at Gangneung beach calculated by the deep-water design waves were significantly less than the observation data. As the return period becomes higher, the significant wave heights obtained by the extreme value analysis becomes higher than those computed by SWAN with the deep-water design waves of the corresponding return periods. KORDI computed the hindcast wave data from January 2004 to August 2008 by WAM with a finer-grid mesh system than those of previous studies. Comparisons of the wave hindcast results with the wave observation show that the reproducibility of the winter-season storm wave was considerably improved compared to the hindcast data from 1979 to 2003. Hereafter, it is necessary to carry out hindcast wave data for the years before 2004 using WAM with the finer-grid mesh system and to supplement the deep-water design wave.

Analysis on the Change of Wave Behaviour Due to Installation of Offshore Wind Turbine Foundations (해상풍력터빈 기초 구조물 설치로 인한 파랑거동 변화 검토)

  • Kim, Ji-Young;Kang, Keum-Seok
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.22 no.5
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    • pp.306-315
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    • 2010
  • As developing the large-scale offshore wind farm is expected, the preliminary environmental impact assessment is very essential. In this study, the wave hindcast model is verified based on observed data at the coast around Wido which is among the candidate sites for developing the offshore wind farm. In addition, the effect of the wind turbine foundations on wave height is analyzed when total 35 wind turbines including monopile foundations of 5 m in diameter are installed. Calculation result of significant wave height is in good accord with observed data since the RMS error is 0.35 m. Moreover, it is found that the presence of the wind turbine foundations hardly affects wave height as wave damping ratio is less than 1%.

Sea State Hindcast for the Korean Seas With a Spectral Wave Model and Validation with Buoy Observation During January 1997

  • Kumar, B. Prasad;Rao, A.D.;Kim, Tae-Hee;Nam, Jae-Cheol;Hong, Chang-Su;Pang, Ig-Chan
    • Journal of the Korean earth science society
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    • v.24 no.1
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    • pp.7-21
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    • 2003
  • The state-of-art third generation wave prediction model WAM was applied to the Korean seas for a winter monsoon period of January 1997. The wind field used in the present study is the global NSCAT-ERS/NCEP blended winds, which was further interpolated using a bi-cubic spline interpolator to fine grid limited area shallow water regime surrounding the Korean seas. To evaluate and investigate the accuracy of WAM, the hindcasted wave heights are compared with observed data from two shallow water buoys off Chil-Bal and Duk-Juk. A detailed study has been carried with the various meteorological parameters in observed buoy data and its inter-dependency on model computed wave fields was also investigated. The RMS error between the observation and model computed wave heights results to 0.489 for Chil-Bal and 0.417 for Duk-Juk. A similar comparison between the observation and interpolated winds off Duk-Juk show RMS error of 2.28 which suggest a good estimate for wave modelling studies.

Analysis of Wave Characteristics near Wangdeungdo through Southwest Sea Wave Hindcasting (서남해 파랑 후측모의 실험을 통한 왕등도 인근 파랑 특성 분석)

  • Young Ju Noh;Min Young Sun
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.36 no.2
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    • pp.61-69
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    • 2024
  • Wave conditions are crucial for offshore wind farm design, particularly in determining structural loads and layout. However, there is limited wave hindcasting research for the Wangdeungdo Island area, a potential offshore wind site. This study used the MIKE21 model for a year-long wave hindcast around Wangdeungdo in 2021. Validation showed high reproducibility for significant wave heights with RMSE values of 0.177 and 0.225 and Pearson correlations of 0.971 and 0.970 at Sangwangdeungdo and Buan buoys. Subsequent analysis of the wave characteristics near Wangdeungdo indicated significant seasonal variations and differences in maximum significant wave heights across locations, which are expected to significantly impact the design loads for offshore wind structures.

Correction Factor for Assessment of Nearshore Wave Energy (근해 파력에너지 산정을 위한 보정 기법에 관한 연구)

  • Kim, Gunwoo;Jeong, Weon Mu;Jun, Kicheon;Lee, Myung Eun
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.05a
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    • pp.164.1-164.1
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    • 2011
  • Previously, many researchers assessed nearshore wave energy in two ways. The first is a simulation with respect to the offshore wave time series to validate the wave buoy data and the wave model results, and the other is to simulate the representative waves of typical seasonal wave conditions. The former requires enormous computational time and effort. The latter yields inspection on the patterns for the spatial and temporal distribution of nearshore wave energy but tends to underestimates the amount of wave energy in the nearshore region owing to the correlation between the significant wave height and wave period. $\ddot{O}$zger et al. (2004) derived the stochastic wave energy formulation by introducing a correction factor explicitly in terms of the covariance of the wave energy and significant wave height. In this study, a correction factor was applied for the assessment of nearshore wave energy obtained by numerical simulation of wave transformation with respect to representative waves.

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Extreme Wave Hindcast in the Neighboring Seas of Korea from Loosely Coupled Wave-Tide-Surge Model (약결합된 해파-조석-해일 모형에 의한 한반도 주변해면의 최극해파 추정)

  • 최병호;엄현민
    • Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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    • 2000.09a
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    • pp.37-46
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    • 2000
  • 한반도 주변해역은 고조위와 태풍의 내습에 의한 강한 파랑으로 특징지워진다. 저조위때에 나타나는 1700$\textrm{km}^2$에 달하는 갯벌로 이루어진 서해안과 황해 동쪽 지역의 해안의 조건은 경기만에 l0m 범위의 높은 조위 차와 동계 계절풍과 태풍으로 인한 4-5m에 달하는 높은 파고를 발생시키는 고에너지와 높은 탁도 환경을 만들어 내는 매개체가 된다. (중략)

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Inner harbour wave agitation using boussinesq wave model

  • Panigrahi, Jitendra K.;Padhy, C.P.;Murty, A.S.N.
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.7 no.1
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    • pp.70-86
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    • 2015
  • Short crested waves play an important role for planning and design of harbours. In this context a numerical simulation is carried out to evaluate wave tranquility inside a real harbour located in east coast of India. The annual offshore wave climate proximity to harbour site is established using Wave Model (WAM) hindcast wave data. The deep water waves are transformed to harbour front using a Near Shore spectral Wave model (NSW). A directional analysis is carried out to determine the probable incident wave directions towards the harbour. Most critical threshold wave height and wave period is chosen for normal operating conditions using exceedence probability analysis. Irregular random waves from various directions are generated confirming to Pierson Moskowitz spectrum at 20m water depth. Wave incident into inner harbor through harbor entrance is performed using Boussinesq Wave model (BW). Wave disturbance experienced inside the harbour and at various berths are analysed. The paper discusses the progresses took place in short wave modeling and it demonstrates application of wave climate for the evaluation of harbor tranquility using various types of wave models.

Coastally Trapped Waves over a Double Shelf Topography(III) : Forced Waves and Circulations Driven by Winds in the Yellow Sea (양향성 대륙붕의 대륙붕파 (III): 강제파와 황해에서의 바람에 의한 해수순환)

  • PANG Ig-Chan
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.25 no.6
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    • pp.457-473
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    • 1992
  • The first order wave equation over a double shelf has wind stresses on both coastal boundaries and wind stress curl forcing across the shelf. In the Yellow Sea, the effect of wind stress curl can be neglected as a forcing of shelf waves. The decay distance of Kelvin waves is much greater than that of continental shelf waves so that Kelvin waves are transmitted nearly intact through the northern embayment. The numerical method of characteristics has been modified to accomodate wave propagation of opposite directions. Using a little more realistic coastline, the wave model hindcast has been improved for current velocity, but hardly for sea level. It means that Kelvin waves, which mainly determine sea levels, are affected little by the change of bottom slope. For a better hindcast of sea level, input energy of Kelvin waves transmitted from the East China Sea is needed. The basic structure of downwind flows along the coasts and upwind flows along the trough supports the seasonal circulations driven by monsoon winds in the Yellow Sea.

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