• Journal of Advanced Marine Engineering and Technology
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• 제32권7호
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• pp.1003-1012
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• 2008

A three dimensional numerical study has been applied to predict the turbulent fluid flow and heat transfer characteristics for the rectangular channel with different types of baffles. Four different types of the baffles are used. The inclined baffles have the width of 19.8 cm, the square diamond type hole having one side length of 2.55 cm, and the inclination angle of $5^{\circ}$. Reynolds number is varied between 23,000 and 57,000. The SST k-${\omega}$ turbulence model is used in the present numerical study. The validity of the numerical results is examined with the experimental data. The numerical results of the flow field depict that the flow patterns around the different baffle type are entirely different and it significantly affects the local heat transfer characteristics. The heat transfer and friction factor depend significantly on the number of baffle holes. It is found that the heat transfer enhancement of baffle type II (3 hole baffle) has the best values.

• Corrosion Science and Technology
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• 제12권5호
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• pp.239-244
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• 2013

Marine equipment exposed to harsh environments requires not only excellent corrosion resistance but also improvement of physical characteristics against natural material degradation. With growing interests in ocean energy resources, the higher reliability for marine equipment has become more important in terms of material characteristics. ALBC3 alloy represents excellent corrosion resistance and is widely used in corrosive environments. However, cavitation damage occurs frequently due to its poor durability in high flow rate of marine environment. In this research, shot peening technology was employed as a surface modification with shot peening stand-off distance to mitigate cavitation damage. The effects of shot peening on extent of cavitation damage and weight loss were evaluated for both shot peened and non-peened specimens. The results revealed that the application of shot peeing decreased cavitation damage for all experimental conditions in comparison with the non-peened specimens. The optimum stand-off distance was determined to be 10 cm, since more than 35 % of cavitation damage reduction was observed.

• 대한조선학회논문집
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• 제49권6호
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• pp.504-511
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• 2012

The objective of this study is to investigate tank container to be used as fuel tank for LNG fueled ship. Feasibility of tank container to the fuel tank of LNG fueled ship is addressed and the advantage of tank container as fuel tank of ship is investigated. Conceptual configuration of the tank container is designed as well as structural analyses based on finite element method are carried out to meet the design regulation suggested by shipping register. Static loading is considered by structural analysis and impact test is performed. It is necessary to require SRS(shock response spectrum) in order to investigate structural safety which can meet.

• 동력기계공학회지
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• 제17권5호
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• pp.30-37
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• 2013

For vessels operating in the cold climate regions, the ballast water inside or hopper tanks above the waterline may be frozen, starting at the top of the tank and at the side walls. Therefore, countermeasures against freeze-up of the ballast tank such as air-bubbling system, hot steam injecting system, heating coil system and water circulating system are taken to prevent freeze-up phenomenon; however, there are no rigorous investigations of anti-freezing to examine the effectiveness and validity of systems against freeze-up of the ballast tank, in which the temperatures are about -$25^{\circ}C$ (ambient air temperature) and $0^{\circ}C$ (sea water), respectively. In this paper, to ensure reasonable specifications for cold regions if the measures from the above-mentioned systems against freeze-up are effective, the phenomenon of ballast tank freeze-up is simulated and discussed in low temperature conditions. With the results using the commercial CFD code, CFX 14, the most cost-effective solution is conducted to prevent being frozen along the outer surface.

• 한국표면공학회지
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• 제46권3호
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• pp.120-125
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• 2013

This investigation was to identify the electrochemical corrosion protection conditions to minimize the cavitation damage by generating hydrogen gas with the means of hydrogen overvoltage before the impact pressure of the cavity is transferred to the surface. The hybrid potentiostatic test method is designed to evaluate a complexed cavitation and electrochemical characteristic for ALBC3 alloy that is diverse and its broad applications fields in marine industry. The surface observation showed that neither the cavitation damage nor the electrochemical damage by the hydrogen gas generation occurred in the potential of -2.6 V under the cavitation environment. In the potentiostatic experiments under the cavitation environment, the cavities were reflected or cancelled out by the collision of the cavities with the hydrogen gas generated by the hydrogen overvoltage.

• 해양환경안전학회지
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• 제18권5호
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• pp.496-504
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• 2012

환경보호 분야에서는 국제협약의 원활한 이행을 위해 당사국 간의 긴밀한 협조가 요구되며, MARPOL 73/78 상 보고의무는 해양환경보호를 위한 국제협력의 일환으로서 중요한 역할을 하고 있다. 이 연구에서는 MARPOL 73/78 상 보고요건의 국제법적 의미에 대하여 살펴보고, 당사국들의 보고의무 이행현황을 조사하였다. 이를 위하여 2001년부터 2010년까지 지난 10년간의 MEPC/Circ.318의 각 항목에 따른 MARPOL 73/78 상 보고의무의 이행현황을 분석하였다. 또 다른 한편으로는 이러한 이행현황에 대한 분석을 통해 당사국의 보고의무 준수율을 향상할 수 있는 개선방안을 제시하였다.

• 한국항공운항학회지
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• 제29권3호
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• pp.24-33
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• 2021

Although it is the first transportation method to apply the 'Ground Effect' applied to aircraft to ships, WIG ships, which are classified as 'Ships' operating on the water under international law. The pilot aptitude test, which has the effect of preventing safety accidents in advance, has not yet been established as a legal system in S. Korea, after being certified by the Korean Register of Shipping (KR) for the first time in the world in March 2020. Therefore, the purpose of this study is to ensure that identifying the importance, recognition, correlation, etc. of the tools and items of aptitude testing, from a group of experts, can be used appropriately for future development of legal aptitude testing tools. As a method of study, the questionnaire method was used, and the analysis confirmed that the tools used on aircraft and ships could be used appropriately. In particular, Due to the characteristics of the WIG ships, it was confirmed that it is necessary to develop more specifically in the future, the operational qualifications and physical fitness items, which are the aptitude evaluation items.

• 한국CDE학회논문집
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• 제19권1호
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• pp.41-49
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• 2014

For the reuse of the existing 3D block model of a ship, we analyze the hull modeling process using AVEVA Marine which is a representative CAD (Computer-Aided Design) system for the shipbuilding. In the AVEVA Marine environment where the design engineer makes 3D model on the 2D view that is so-called 2.5D, it cannot be possible to copy to reuse the block model just simply copying the 3D feature model itself like in the general mechanical CAD system or Smart Marine 3D which are on the basis of the 3D model representation. In this paper, we analyze the scheme file where the 3D model is defined in AVEVA Marine so that we develop the program for the block copy and the translation using this scheme file. It is significant that this program can be immediately available as a real-world application on the AVEVA Marine environment.

• 대한조선학회지
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• 제24권4호
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• pp.19-36
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• 1987

In this research the coupling problem between the elastic structure and the fluid, specially the hydroelastic harmonic vibration problem, is studied. In order to couple the domains, i.e., the structural domain and the fluid domain, the boundary integral method(direct boundary integral formulation) is used in the fluid domain in combination with the finite element method for the structure. The boundary integral method has been widely developed to apply it to the hydroelastic vibration problem. The hybrid boundary integral method using eigenfunctions on the radiation boundaries and the boundary integral method using the series form image-functions to replace the even bottom and free surface boundaries in case of high frequencies have been developed and tested. According to the boundary conditions and the frequency ranges the different boundary integral methods with the different idealizations of the fluid boundaries have been studied. Using the same interpolation functions for the pressure distribution and the displacement the two domains have been coupled and using Hamilton principle the solution of the hydroelastic have been obtained through the direct minimizing process. It has become evident that the finite-boundary element method combining with the eigenfunction or the image-function method give good results in comparison with the experimental ones and the other numerical results by the finite element method.

• Journal of Advanced Marine Engineering and Technology
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• 제38권3호
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• pp.318-324
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• 2014

선원대피처는 해적의 승선침입이 임박한 상황에서 모든 선원이 피난할 목적으로 본선 내부에 지정 설치된 장소로서 해적의 침입시도에 일정기간 동안 버틸 수 있는 구조로 만들어져야한다. 국내외 규정에 따라 선박의 은밀한 장소에 설치되는 선원 대피처는 중화기로 무장한 소말리아 해적으로부터 선원들의 안전을 확보하는 데에 필요한 최후의 보루가 되고 있다. 본 연구에서는 선원 대피처에 관련된 국내외 규정에 대한 검토와 고찰을 통하여 현행 규정에 따른 선원대피처의 한계, 취약점 등을 식별하고, 우리나라 선박설비기준의 요건을 중심으로 향후 보다 안전하고 적용 가능한 개선 방안을 제시하였다.