• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.1
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• pp.40-46
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• 2017

Shipping activities have become possible in the Arctic Ocean due to melting ice by global warming. An increasing number of vessels are passing through the Arctic Ocean consequently bringing concerns of ship-iceberg collisions. Thus, most classification societies have implemented regulations to determine requirements for ice strengthening in ship structures. This paper presents the simulation results of an ice-strengthened polar class ship after an iceberg collision. The ice-strengthened polar class ship was created in accordance with the Unified Requirements for a Polar-Ship (IACS URI). An elastic-perfect plastic ice model was adopted for this simulation with a spherical shape. A Tsai-Wu yield surface was also used for the ice model. Collision simulations were conducted under the commercial code LS-DYNA 971. Hull deformations on the ice-strengthened foreship structure and collision interaction forces have been analysed in this paper. A normal-strength ship structure in an iceberg collision was also simulated to present comparison results. Distinct differences in structural strength against ice impact forces were shown between the ice-strengthened and normal-strength ship structures in the simulation results. About 1.8 m depth of hull deformation was found on the normal ship, whereas 1.0 m depth of hull deformation was left on the ice-strengthened polar class ship.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.379-381
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• 2011

2010년 3월 22일 "Ice Navigation"에 대한 경험과 자료 수집을 위하여 통영항(평택항)과 Sakhalin "Prigorodnoye항"을 운항하는 대한해운 소속의 "K. Jasmine"호를 승선하여 "Prigorodnoye항"에서 LNG $143,700M^3$를 선적하여 "통영항"에서 양하하는 과정을 경험하고 하선하였다. "K. Jasmine"호는 년 150만톤의 LNG 수입을 위한 "한국 ${\leftrightarrow}$ Sakhalin Project"에 투입된 LNG운반선으로서 "Russian Maritime Register of Shipping"의 "Ice Class LU2" 증서를 갖고 있는 선박이다. 이 증서는 선박이 60Cm 두께의 얼음 해역에서 Ice Breaker의 인도 아래 4Knots 이상의 선속을 유지할 수 있음을 보장받고 있다. 운항중 SEIC(Sakhalin Energy Investment Company)에서는 Ice map을 매일 제공하는 하고 있었으며, 이를 참조하여 본선에서는 계획된 항해를 수행하였다. 이 논문에서는 Ice Navigation선박의 성능 조건에 대하여 검토하여 향후 이 항로에 취항하는 선박에 지침이 되고자 한다.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.1
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• pp.294-306
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• 2019

On the basis of the Computational Fluid Dynamics technique (CFD) combined with the overlap grid method, this paper establishes a numerical simulation method to study the problem of ice-propeller interaction in viscous flow and carries out a simulation forecast of the hydrodynamic performance of an ice-class propeller and flow characteristics when in the proximity of milling-shape ice (i.e., an ice block with a groove cut by a high-speed revolving propeller). We use a trimmed mesh in the entire calculation domain and use the overlap grid method to transfer information between the domains of propeller rotation calculation and ice-surface computing. The grid is refined in the narrow gap between the ice and propeller to ensure the accuracy of the flow field. Comparison with the results of the experiment reveals that the error of the hydrodynamic performance is within 5%. This confirms the feasibility of the calculation method. In this paper, we calculate the exciting force of the propeller, analyze the time domain of the exciting force, and obtain the curve of the frequency domain using a Fourier transform of the time-domain curve of the exciting force. The existence of milling-shape ice before the propeller can greatly disturb the wake flow field. Unlike in open water, the propeller bearing capacity shows a downward trend in three stages, and fluctuating pressure is more disordered near the ice.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.5
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• pp.513-522
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• 2008

In this paper, one of the widely-used ice resistance prediction methods, introduced by Spencer(1992) of the Institute for Ocean Technology, Canada, is reviewed. Spencer's component-based scaling system for ship-ice model tests is analysed to estimate the ice resistance of various types of icebreaking vessels (Canadian MV Arctic, Terry Fox, R-Class icebreaker, US icebreakers Polar Star and Healy, Russian SA-15 cargo ships, Japanese PM Teshio and a model ship). The general form and the non-dimensional coefficients in ice resistance prediction formula are obtained using the published ice model test and full-scale sea trial data. The applicability of Spencer's method on R-Class icebreaker is discussed to estimate ice resistance for the larger icebreaking cargo vessels. Additional parameters to account for the difference in hull forms of icebreakers and cargo vessels are recommended to be included in the Spencer's original ice resistance prediction formula.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.5
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• pp.562-568
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• 2008

In this study, the target FSICR class is 1A whose target thickness of the brash ice is 46 mm in model scale. Normally ice floes for brash ice do not exceed 2 m in full scale, so the model ice sheet was cut by about 10 cm by 10 cm using hand saws. Since the target thickness of brash ice is 46 mm, 46 mm ice sheet makes one layer brash ice. For 23 mm thickness ice sheet, two layers should be accumulated to reach 46mm brash ice thickness. For 15mm thickness ice sheet, three layers need to be accumulated as the same as those in 23 mm ice sheet. New methodology to produce a brash ice was proposed. The results showed that it would be important to use multi-layer rather than single layer possibly because of significant thrust deduction from the propeller-ice interaction in the present ice condition (FSICR 1A).

• Journal of the Society of Naval Architects of Korea
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• v.48 no.5
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• pp.390-395
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• 2011

The main purpose of ice model basin is to assess and evaluate the performance of the Arctic ships and offshore structures because the full-scale tests in ice covered sea are usually very expensive and difficult. There are various ice conditions, such as level ice, brash ice, pack ice and ice ridge, in the real sea. To estimate their capacities in ice tank accurately, an appropriate model ice sheet and prepared ice conditions copied from actual sea ice conditions are needed. Pack ice is a floating ice that has been driven together into a single mass and a mixture of ice fragments of varying size and age that are squeezed together and cover the sea surface with little or no open water. So Ice-class vessels and Icebreaker are usually operated in pack ice conditions for the long time of her voyage. The most ice model tests include the pack ice test with the change of pack ice concentration. In this paper, the effect of pack ice size and channel breadth in pack ice model test is conducted and analyzed. Also we presented some techniques for the calculation of pack ice concentration in the model test. Finally, we developed a new model test methodology of pack ice condition in square type ice tank.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.17-18
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• 2006

최근 중동지방의 정세 불안과 원유 자원의 고갈로 인한 대체 지역으로 러시아 시베리아 유전이 각광을 받고 있임. 시베리아 유전 원유 수송이 파이프라인을 통해 발틱 연안에 위치한 프리모스크항 도달하여 해상을 통한 원유 수출이 증가함에 따라 ICE Class 대형 Tanker의 수요가 급격히 증가하고 있는 실정.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.10a
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• pp.110-111
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• 2013

우리나라 현대 글로비스사는 스웨덴의 Stena 해운사 소속인 M/T Stena Polaris호를 용선하여 화물(납사, 43,838톤)을 싣고 2013년 9월 15일 러시아 Ust Luga항을 출항하여 약 8,100마일 북극해 항로(North Sea Route)를 통하여 10월 17일경 여수 사포 1부두에 입항할 예정이다. 이는 금년 5월 15일 "북극해 이사회"의 영구옵서버 자격을 취득과 더블어 새로운 물류 시대의 개막이라고 할 수 있겠다. 이런 시점에서 한국해양수산연수원은 국내 Ice Navigator 교육시장 선점과 세계적 교육기관으로 도약을 하기 위하여 교육과정을 개설준비 하고 있으며, 금번 시범운항 행사를 위하여 방문한 9월 13일 Ice Navigation Training 교육과정이 이미 개설되어 있는 Russia Admiral Makarov State Maritime Academy측 총장 및 관계자와 Russia교수진의 협력 및 NSR 통과 선박의 승선실습을 요청하였으며, 교육인증을 위한 협력도 추진하기로 하였다. 따라서 현재 북극해 항로현황과 Ice Navigator교육과정 개발에 대하여 검토해 보고자 한다.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.326-336
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• 1997

Four ice nucleation-active bacteria (INA-bacteria), Pseudomonas syringae, Xanthomonas campestris, Escherichia coli JM109/pEIN229 and Gluconobacter oxydans/pKIN230, were treated with heat, pressure and gamma-irradiation to compare viability and their ice nucleation activity (INA) after sterilization. Gamma-irradiated INA-bacteria showed the least decrease in T90 value (the temperature at which the 90% of drops are frozen). According to cumulative INA spectra, gamma-irradiated INA-bacteria showed little decrease in class A ice nuclei $(nucleate\;H_{2}O\;at\;higher\;than\;-5^{\circ}C)$, pressurized INA-bacteria showed more than 90% decrease in class A ice nuclei, and heat-treated INA-bacteria barely showed class A ice nuclei. Differential scanning calorimetry (DSC) was used to examine the effect of INA-bacteria on the thermophysical properties of water at freezing temperature. Freezing peaks were appeared at about $11{\sim}15^{\circ}C$ higher on thermograms and enthalpies of phase change were decreased for the water containing INA-bacteria compared with the pure water, while melting peaks were not shifted. INA measured by DSC method were significantly correlated with INA measured by drop freezing method $(R^{2}>0.993,\;p<0.0001)$, indicating that DSC can be used as a new, simple and precise method for measuring INA.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.2
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• pp.135-142
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• 2019

Ice accretions on the ship equipment and areas are the most common issues for vessels operating in cold climate and ice-covered waters and it has effect on the vessel safety and operability of equipment and systems, thus ship machineries and structures exposed to low temperature environments should satisfy the winterization requirements specified in ice class rules. The main objective of this study is to review the state-of-the-art of winterization trend for vessels navigating in ice-covered waters. The hazard of icing and how ice accretions affect operations and safety are investigated firstly, and then winterized notations for each classification are summarized. In addition, winterization methods currently used in vessels operating in ice-covered waters are investigated for a better understanding of effective approach and its application. This information will provide a framework for future winterization issues to mitigate the ice accretion phenomena.