• Title/Summary/Keyword: sea state

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Rolling Dynamic Response Analysis of Mobile Harbor Crane by Sea State 3 Wave Excitation (해상상태 3의 파고에 따른 모바일 하버 크레인의 롤링 동응답 해석)

  • Han, Ki-Chul;Hwang, Soon-Wook;Choi, Eun-Ho;Cho, Jin-Rae;Lim, O-Kaung
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.23 no.5
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    • pp.493-499
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    • 2010
  • In the sea-floating logistics port called mobile harbor a crane system with the different structure from the conventional above-ground container crane is installed. And, the dynamic stability of whole mobile harbor by the wave excitation is definitely affected by the crane positioned at the top. This paper is concerned with the dynamic rolling analysis of the mobile harbor subject to sea state 3 wave excitation, for which two-step analysis procedure composed of theoretical and numerical approaches is employed. First, the rigid rolling of mobile harbor is obtained according to the linear wave theory. And then, the dynamic rolling response of the flexible crane system caused by the rolling excitation of mobile harbor is analyzed by finite element analysis. The coupled interaction effect between the sea wave and the mobile harbor is taken into consideration by the added mass technique.

Case Study on the State of Sea Surface with Low Atmospheric Pressure and Typhoon Conditions over the fellow Sea (저기압 및 태풍 통과시 서해상의 해상상태 사례 분석)

  • Pang, Ig-Chan;Lee, Ho-Man;Kim, Tae-Hee
    • Journal of the Korean earth science society
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    • v.25 no.4
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    • pp.277-288
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    • 2004
  • In this study, state of sea surface were analyzed comparatively for cases of low atmospheric pressure, which occurred in the middle area of China and moved eastward to the Korean Peninsula across the Yellow sea during April 9-12, 1999, and typhoons 'NEIL' May 1999 and 'OLGA' July 1999, which moved northward along the west coast of the Korean Peninsula. In cases of low pressure, wind speeds and phases were respectively stronger and faster in the center area than in the surrounding areas. The wave heights seem to a somewhat differing tendency from that of the wind speeds due to the influences of geometry. On the other hand, wave heights were lower under typhoon weather than under low pressures, except the instance of wave height over 5 m on Chilbal when typhoon Olga pass northward from the southern area. Storm surges also showed larger amplitudes under low pressures than under typhoons. The results suggest that wave sand storm surges may be larger for a slow passing synoptic low pressures than for a fast passing local typhoon.

Analysis of High Sea-worthiness Offshore Wind Turbine (고 내항성 해상풍력 발전기 해석)

  • Ahn, Gyu-Jung;Koo, Bon-Guk
    • Journal of the Institute of Convergence Signal Processing
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    • v.22 no.4
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    • pp.164-170
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    • 2021
  • Research was conducted to analyze and improve the kinetic performance of offshore wind power generators. The shape used in this study was taken with reference to the previous paper, and the size of the repair area was designed at 80%, 60%, 40%, and 20%, respectively, and the exercise performance was confirmed accordingly. The sea state was calculated in Sea State 4, 5, and 6. In the calculation process, the calculation was performed using commercial computational hydrodynamics (ANSYS) and AQUA. In the case of overall exercise performance, it was confirmed that the smaller the size of the repair area, the smaller the exercise such as heave, roll, and pitch. However, it was confirmed that in the case of a shape in which the size of the repair area was rapidly reduced, there may be cases in which the restoration performance was not satisfied when the restoration calculation was performed. In addition, it was confirmed that there may be an appropriate repair surface depending on the sea condition.

Salt and Sand Transport from Aral Sea Basin

  • Lee, Kwi-Joo;Shugan, Igor;Park, Na-Ra;Begmatov, A.;Mamatova, N.T.;Lee, Chung-Hwan
    • Journal of Ocean Engineering and Technology
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    • v.19 no.3
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    • pp.47-53
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    • 2005
  • Model for dust and salt transportation from the dried bottom of the Aral Sea is suggested. Theoretical analysis is based on the turbulent diffusion equation for the averaged function of passive impurity concentration. One-layer model of the atmospheric boundary layer is assumed. Impurity precipitation rates are calculated as the functions of the particle size and the distance source of particles. Analytical solutions for the point and two-dimensional sources of impurities are found. Model calculations for salt and sand transport from the Aral Sea basin are made on the basis of 2D source model with a constant intensity.

Effects of Critical Minimum Depth in the Coastal Region on Storm Surges using a Three-Dimensional Numerical Experiment (폭풍해일 예측 수치실험에 미치는 연안역 임계최소수심의 영향)

  • Hong, Chul-Hoon
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.47 no.2
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    • pp.168-173
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    • 2014
  • The effect of critical minimum depth in the coastal region on storm surges was examined using a three-dimensional primitive equation model (POM). Case studies using numerical experiments in a small coastal bay in the southern sea of Korea (Hanam Bay) have examined the 'critical depth' (CD) that stabilizes the numerical calculations. Dependence of the CD of typhoon tracks and tidal components such as M2, S2, O1, and K1 were examined. The model results clearly demonstrated that the numerically unstable state of the calculation was caused by the coarse resolution of sea surface elevation.

A Study on the Motion Sickness Incidence due to Sea State and Location of the Training Ship Kaya (실습선 가야호의 해상상태와 선내 위치에 따른 뱃멀미 지수에 관한 연구)

  • Han, Seung-Jae;Ha, Young-Rok;Kim, Jong-Hwa;Lee, Jong-Gun;Kim, In-Chul
    • Journal of Fisheries and Marine Sciences Education
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    • v.26 no.1
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    • pp.126-133
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    • 2014
  • For boarding comfort and pleasant boarding sensitivity of passenger in passenger ship, there are a few methods such as motion sickness rate or MSI(Motion Sickness Incidence) to assess safety of passenger ship. To find out MSI or motion sickness rate of the training vessel Kaya of Pukyong National University, we use lots of various factors: sea condition, incident angle in main sail way, economic speed, calculation position of motion sickness, sea state, work place and reduce zone of ship. In this paper, we adopted Maxsurf Seakeeper program based on Strip Theory and carefully compared theoretical results with experimental results.

Developments in Hull Strength Monitoring (Developments in Hull Strength Monitoring)

  • P. A. Thomson;Ph. D BMT SeaTech Ltd.
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.2 no.1
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    • pp.143-143
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    • 1996
  • Recent Class requirements and IMO recommendations concerning Hull Strength Monitoring (HSM) have prompted an increasing number of shipowner to adopt monitoring systems on bulk carriers and tanker. Such systems are designed to give warning when stress levels and the frequency and magnitude of ship motions approach levels which require corrective action. When fitted these systems provide enhanced operational safety and efficiency. This paper describes a development beyond the standard BMT HSM system through the integration of stress, motion and radar-based sea state monitoring with powerful, on-board, artificial intelligence (AI) tools. The latter utilises conceptual clustering techniques as an aid to pattern recognition in stress, fatigue. motion and sea state data clusters. This, in turn, provides additional operational guidance for ship's staff. Feedback from applications of the standard BMT HSM and extended HSM systems on board the British Steel Bulk Shipping fleet is described.

Wide Sargasso Sea: An Elegy of Class Conflict in Jamaica

  • Park, Jai Young
    • Journal of English Language & Literature
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    • v.57 no.6
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    • pp.1199-1212
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    • 2011
  • This paper is to scrutinize Jean Rhys' Wide Sargasso Sea through a Marxist criticism. While critics were industriously excavating discourses of feminism, post-colonialism, and racism in the novel, they tended to regard the Marxist attribute as supplementary material and to diminish the significance not considering as an independent subject to be examined. However, the novel, in which all the major relationships are based on capital, exemplifies class conflict between the bourgeois and the proletariat. Marx and Engels believe that the foundation of our society is capital and that society evolves through class conflict to obtain more capital, and thus they assert people's relations are the product of the commodification of individuals. Furthering their study, Louis Althusser specifies the power system through the (repressive) state apparatus and the ideological state apparatus. With the theories of the thinkers' above, this paper analyzes the relationship between Annette and Mason, Antoinette and her nameless husband, allegedly Rochester, Rochester and Amelie, and Rochester and Daniel Cosway. This paper offers an alternative reading of a classical feminist and post-colonial text.