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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Society of Naval Architects of Korea
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Journal DOI :
The Society of Naval Architects of Korea
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Volume & Issues
Volume 49, Issue 6 - Dec 2012
Volume 49, Issue 5 - Oct 2012
Volume 49, Issue 4 - Aug 2012
Volume 49, Issue 3 - Jun 2012
Volume 49, Issue 2 - Apr 2012
Volume 49, Issue 1 - Feb 2012
Selecting the target year
SIS Design for Fuel Gas Supply System of Dual Fuel Engine based on Safety Integrity Level(SIL)
Kang, Nak-Won ; Park, Jae-Hong ; Choung, Choung-Ho ; Na, Seong ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 6, 2012, Pages 447~460
DOI : 10.3744/SNAK.2012.49.6.447
In this study, the shutdown system of the fuel gas supply system is designed based on the Safety Integrity Level of IEC 61508 and IEC 61511. First of all, the individual risk(
/year) and the risk matrix which are the risk acceptance criteria are set up for the qualitative risk assessment such as the HAZOP study. The natural gas leakage at the gas supply pipe is identified as the highest risk among the hazards identified through the HAZOP study and as a safety instrumented function the shutdown function for leakage was defined. SIL 2 and PFD(
) for the shutdown function are determined by the layer of protection analysis(LOPA). The shutdown system(SIS) carrying out the shutdown function(SIF) is verified and designed according to qualitative and quantitative requirements of IEC 61508 and IEC 61511. As a result of SIL verification and SIS conceptual design, the shutdown system is composed of two gas detectors voted 1oo2, one programmable logic solver, and two shutdown valve voted 1oo2.
Analysis of Large-Amplitude Ship Motions Using a Cartesian-Gridbased Computational Method
Yang, Kyung-Kyu ; Nam, Bo-Woo ; Lee, Jae-Hoon ; Kim, Yonghwan ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 6, 2012, Pages 461~468
DOI : 10.3744/SNAK.2012.49.6.461
In this study, a Cartesian-grid method based on finite volume approach is applied to simulate the ship motions in large amplitude waves. Fractional step method is applied for pressure-velocity coupling and TVD limiter is used to interpolate the cell face value for the discretization of convective term. Water, air, and solid phases are identified by using the concept of volume-fraction function for each phase. In order to capture the interface between air and water, the tangent of hyperbola for interface capturing (THINC) scheme is used with weighed line interface calculation (WLIC) method which considers multidimensional information. The volume fraction of solid body embedded in the Cartesian grid system is calculated using a level-set based algorithm, and the body boundary condition is imposed by a volume weighted formula. Numerical simulations for the two-dimensional barge type model and Wigley hull in linear waves have been carried out to validate the newly developed code. To demonstrate the applicability for highly nonlinear wave-body interactions such as green water on the deck, numerical analysis on the large-amplitude motion of S175 containership is conducted and all computational results are compared with experimental data.
An Analysis of Ice Impact Force Characteristics for the Arctic Structure Shape
Jeong, Seong-Yeob ; Cho, Seong-Rak ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 6, 2012, Pages 469~477
DOI : 10.3744/SNAK.2012.49.6.469
This paper describes the characteristic analysis of ice impact force for the Arctic structure shape. In the present study an energy method has been used to predict the impact force during the ice-structure collision. This study also employs two concepts for reference contact area and normalized stress in analysis procedure. The influences of factors, such as impact velocity, full penetration depth, structure shape and ice floe size, are investigated. Full penetration occurs, particularly at lower impact velocity when ice thickness increase. But "typical size" ice floe does not expected ever to achieve full penetration during the impact procedure. The structure shape is the dominant factor in ice impact force characteristic. The results for various ice-structure collision scenarios are analyzed.
Speed Trial Analysis of Korean Ice Breaking Research Vessel `Araon` on the Big Floes
Kim, Hyun Soo ; Lee, Chun-Ju ; Choi, Kyungsik ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 6, 2012, Pages 478~483
DOI : 10.3744/SNAK.2012.49.6.478
The speed performances of ice sea trial on the Arctic(2010 & 2011) area were shown different results depend on the ice floe size. Penetration phenomena of level ice was not happened on medium ice floe and tore up by the impact force because the mass of medium ice floe is similar to the mass of Araon which is Korean ice breaking research vessel and did not shut up by the ice ridge or iceberg. The sea trial on the Amundsen sea was performed at the big floe which is classified by WMO(World Meteorological Organization). Three measurements of ice properties and five results of speed trial were obtained with different ice thicknesses and engine powers. To evaluate speed of level ice trial and model test results at the same ice thickness and engine power, the correction method of HSVA(Hamburg Ship Model Basin) was used. The thickness, snow effect, flexural strength and friction coefficient were corrected to compare the speed of sea trial. The analyzed speed at 1.03m thickness of big floe was 5.85 knots at 10MW power and it`s 6.10 knots at 1.0m ice thickness and the same power. It`s bigger than the results of level ice because big floe was also slightly tore up by the impact force of vessel based on the observation of recorded video.
Proper Orthogonal Decomposition of Pressure Fluctuations in Moonpool
Lee, Sang Bong ; Woo, Bum ; Park, Dong Woo ; Ahn, You Won ; Go, Seok Cheon ; Seo, Heung Won ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 6, 2012, Pages 484~490
DOI : 10.3744/SNAK.2012.49.6.484
Experiments of circulating water channel and two dimensional numerical simulations were performed to investigate the fluctuating characteristics of pressure in moonpool. Based on the quasi-two dimensional characteristics of pressure fluctuations disclosed by the spatial cross-correlations, the numerical results showed qualitatively good agreement with experimental data. Proper orthogonal decomposition was employed to the spatial distributions of pressure fluctuations in order to find the first and second modes of fluctuations. The first mode of pressure fluctuations showed that the fluctuating characteristics of pressure were related to the behaviors of vortical structures. The velocity fluctuations were conditionally averaged to make clear that the coherent structures were responsible for the pressure fluctuations in moonpool.
Hull-Form Development of a Twin-Skeg Large Ro-Pax Ferry
Lee, Hwa Joon ; Jang, Hag-Soo ; Hong, Chun-Beom ; Ahn, Sung-Mok ; Chun, Ho-Hwan ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 6, 2012, Pages 491~497
DOI : 10.3744/SNAK.2012.49.6.491
A hull-form for a 32,000G/T class Ro-Pax ferry has developed in accordance with a need of ferry operators to reduce fuel oil consumption(FOC) due to the drastic increase in oil prices recently and strengthening of environmental rules and regulations such as CO2 emission. A twin-skeg type is applied as the hull-form in lieu of an open-shaft type in order to improve propulsion performance. In order to achieve this object, flow control devices are installed to reduce a propeller induced vibration which is a main reason to obstruct the application of twin-skeg type passenger vessels owing to an uncomfortable vibration level. Numerical simulation by using an in-house code and a commercial code (Fluent) has performed to find out an optimum design of the flow control devices and to check an improvement in cavity volume. Model tests in Samsung Ship Model Basin are carried out to evaluate propulsion performance with the developed twin-skeg type hull and a reference hull of open-shaft type. In conclusion, it is shown that the twin-skeg type hull is better than the open-shaft in FOC by around 7% and in cavity volume by 20% as well.
Vibration Source Signal Identification of Structures Using ICA
Kim, Kookhyun ; Kwon, Hyuk-Min ; Cho, Dae-Seung ; Kim, Jae-Ho ; Jun, Jae-Jin ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 6, 2012, Pages 498~503
DOI : 10.3744/SNAK.2012.49.6.498
Independent component analysis (ICA) technique based on statistical independency of the signals is known as suitable to identify the source signals by measuring and separating mixed signals through transfer paths and has successfully applied in the field of medical care, communications and so forth. In this study, the ICA technique is introduced for the identification of excitation sources from measured vibration signals of structures, which can be done by evaluating negentropy of centered and whitened vibration signals and correlation of separated signals. To validate the method, numerical analyses are carried out for a plate and a cylinder structure. The results show that the method can be applied efficiently to source identification of complex structures. Nevertheless, additional studies would be required to complement problems of occasional inaccuracy.
A Study and Design on Tank Container for Fuel Tank of LNG Fueled Ship
Kim, Tae-Woo ; Suh, Yong-Suk ; Jang, Ki-Bok ; Chun, Min-Sung ; Lee, Kang-Dae ; Cha, Kyong-Ho ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 6, 2012, Pages 504~511
DOI : 10.3744/SNAK.2012.49.6.504
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.
A Numerical Study on the Drag of Axial Cylinder
Lee, Hyun-Bae ; Choi, Jung-Kyu ; Kim, Hyoung-Tae ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 6, 2012, Pages 512~520
DOI : 10.3744/SNAK.2012.49.6.512
In this study, the numerical analysis for the flows around an axial cylinder is carried out in order to investigate the basic characteristics of drag of blunt body. A variation of drag and flow separation for the axial cylinder is investigated according to the length-diameter ratio. Also, the flow separation around the head is removed by rounding-off the front edge of the body to analyze the effect of drag reduction. Most of the drag turns out to be a pressure drag component and the variation of drag is caused by the change of pressure and velocity which is affected strongly by the flow separation at the edges of the axial cylinder. Especially, it is found that the pressure drag component acting on the back of axial cylinder, as known as the base drag, mainly changes the drag. As the length-diameter ratio of axial cylinder increases, the drag sharply decreases and the minimum is shown when the length-diameter ratio is about 2.4. Also, as the length-diameter ratio increases further above 2.4, the drag increases at a slower rate. The pressure drag is almost constant when the length-diameter ratio is greater than 8, but the increase of friction drag component is the reason for the increase of the drag. When flow separation is removed completely at the front edge of the axial cylinder, the pressure drag component is reduced to 12~17%, but the total drag is reduced to only 17%~32% due to the friction drag component that increases linearly proportional to the length-diameter ratio.
Enhanced Manufacturing and Performance Analysis of Flexible Composite Propeller
Lee, Sang-Gab ; Nam, Jae-Hyung ; Hyun, Beom-Soo ; Paik, Bu-Geun ; Lee, Chang-Sup ; Jang, Hyun-Gil ; Nho, In Sik ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 6, 2012, Pages 521~527
DOI : 10.3744/SNAK.2012.49.6.521
It is well known that flexible composite material propeller has superior radiation noise characteristics with outstanding damping effects. In this paper, three flexible composite material propellers were produced using compression molding process, and their hydrodynamic performances and radiation noise characteristics were measured. One propeller, C1, was made up from carbon/epoxy composite laminates, and the other two ones, G1 and G2, from glass/epoxy ones. Their fiber arrays were selected by the progressive damage structural analysis of propellers using composite material model MAT_162 (Composite_DMG_MSC) linked with LS-DYNA code. Carbon/epoxy and glass/epoxy composite specimen tests were performed, their damage mechanisms were figured out, and their parameters were calibrated by their progressive damage structural analysis according to their damage criteria.
Design Algorithm of Flexible Propeller by Fluid-Structure Interactive Analysis
Jang, Hyun-Gil ; Nho, In Sik ; Hong, Chang-Ho ; Lee, Chang-Sup ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 6, 2012, Pages 528~533
DOI : 10.3744/SNAK.2012.49.6.528
Flexible composite propellers are subject to large deformation under heavy loading, and hence the hydrodynamic performance of deformed propeller might deviate from that of the metallic propeller under negligible deformation. To design the flexible propeller, it is therefore necessary to be able to evaluate the structural response of the blades to the hydrodynamic loadings, and then the influence of the blade deformation upon the hydrodynamic loadings. We use the lifting-surface-theory-based propeller analysis and design codes in solving the hydrodynamic problem, and the finite-element-method program formulated with 20-node iso-parametric solid elements for the analysis of the structural response. The two different hydrodynamic and structural programs are arranged to communicate through the carefully-designed interface scheme which leads to the derivation of the geometric parameters such as the pitch, the rake and the skew distributions common to both programs. The design of flexible propellers, suitable for manufacturing, is shown to perform the required thrust performance when deformed in operation. Sample design shows the fast iteration scheme and the robustness of the design procedure of the flexible propellers.
A Comparison Study on the Simplified Formulae for Ship Motion and Global Loads in Waves
Choi, Mun-Gwan ; Park, In-Kyu ; Koo, Weoncheol ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 6, 2012, Pages 534~540
DOI : 10.3744/SNAK.2012.49.6.534
The global performance of various ships estimated by simplified formulae of classification societies is compared with the numerical results by a strip-theory-based whipping analysis program including slamming impact(USLAM). Heave acceleration, pitch angle and the vertical acceleration are compared and the effectiveness of simplified formulae is evaluated. Four different ship models are used for comparison study, which include S175, Flokstra, 6000TEU and 8100TEU container ships. In order to verify the numerical results, the vertical bending moment of S175 is compared with the results of ITTC workshop data.
A Study on the Anti-Icing Performance Evaluating and Design Guide by Heating Coil for Upper Deck of Icebreaking Vessels
Lee, Jong-Chan ; Seo, Young-Kyo ; Lee, Chun-Ju ;
Journal of the Society of Naval Architects of Korea, volume 49, issue 6, 2012, Pages 541~549
DOI : 10.3744/SNAK.2012.49.6.541
The study adopted a freezing prevention method of the upper deck which used heating coil, and carried out numerical analysis by using ANSYS 13.0 CFD for design guide of the vessel operating in cold region. It is based on the experimental results of the anti-icing performance tests which were carried at cold room chamber in MOERI. Numerical analysis for the design guide was performed by considering S.S.T. (Shear Stress Transport) turbulent model for flow separation effects and the turbulence which occurred in interfaces of the numerical model in order to express appropriate heat transmission phenomenon. The numerical result shows average temperature of the upper deck surface appeared similarly compared with the indoor chamber test. The design guide for optimum freezing prevention presented through heat transmission capability and interval of the heat coil in various outdoor temperature(
) and wind speed(1m/s~7m/s).