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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
Journal Basic Information
Journal DOI :
The Society of Naval Architects of Korea
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Volume & Issues
Volume 51, Issue 6 - Dec 2014
Volume 51, Issue 5 - Oct 2014
Volume 51, Issue 4 - Aug 2014
Volume 51, Issue 3 - Jun 2014
Volume 51, Issue 2 - Apr 2014
Volume 51, Issue 1 - Feb 2014
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A Comparison and Analysis of Ship Optimal Routing Scenarios considering Ocean Environment
Park, Jinmo ; Kim, Nakwan ;
Journal of the Society of Naval Architects of Korea, volume 51, issue 2, 2014, Pages 99~106
DOI : 10.3744/SNAK.2014.51.2.99
Weather routing of a ship provides an optimal route to the destination by using minimal time or fuel in a given sea condition. These days, weather routing came into a spotlight with soaring fuel price and the environmental regulations of IMO and several countries. This study presents three scenarios of voyaging strategies for a ship and compared them in terms of the fuel consumption. The first strategy fixes the speed of a ship as a constant value for entire sailing course, the second fixes the RPM of the ship as constant for entire course, and the third determines the RPMs of the ship for each segment of the course. For each strategy, a ship route is optimized by using the
search method. Wind, ocean current and wave are considered as ocean environment factors when seeking the optimal routes. Based on 7000 TEU container ship`s sea trial records, simulation has been conducted for three scenarios, and the most efficient routing scenario is determined in the view of fuel consumption.
A Study on Analysis of Ice Load Measured during the Voyage in the Arctic Sea
Lee, Tak-Kee ; Kim, Tae-Wook ; Rim, Chae Whan ; Kim, Heung-Sub ;
Journal of the Society of Naval Architects of Korea, volume 51, issue 2, 2014, Pages 107~113
DOI : 10.3744/SNAK.2014.51.2.107
The icebreaking research vessel, ARAON had her second ice trial in the Arctic Sea from 16th July to 12th August 2010. During the voyage, the local ice loads acting on the bow of port side were measured from 14 strain gauges. The measurements were also carried out in ice waters with various ice concentration ratio as well as the icebreaking performance tests. In this study, the ice loads measured during the `general` operation in ice waters were analyzed. As a first step, the relationship between the location of strain gauges and the ice loads were investigated, and then the possibility for observation of higher ice loads was estimated based on the probability density function. The relationship between the ship speed and the ice load was also investigated. 718 peak stresses data higher than 20 MPa obtained from strain gauges array attached in longitudinally and vertically was analyzed. In general, the ice load increases as the ship speed increases in the low ship speed range, and ice load decreases as the ship speed is greater than a certain speed.
Strength Assessment of LNG CCS using Strength Analysis Method for Composite Materials
Jeong, Han Koo ; Yang, Young Soon ;
Journal of the Society of Naval Architects of Korea, volume 51, issue 2, 2014, Pages 114~121
DOI : 10.3744/SNAK.2014.51.2.114
Liquefied natural gas(LNG) cargo containment system(CCS) has the primary function of ensuring both adequate structural safety with respect to sloshing load which is defined as a violent behaviour of the liquid contents in CCS due to external forced motions and thermal insulation keeping natural gas below its boiling point. Among different LNG CCS types such as independent B-type and membrane ones, Mark III CCS is considered in this paper to perform its strength assessment. Mark III CCS plate is designed and constructed by stacking various non-metallic engineering materials such as plywood, triplex, reinforced PU foam that are supported by series of mastic upon inner steel hull structure. From the viewpoint of structural analysis, this plated structure is treated as a laminated composite structure showing complex structural behaviour under external load. Advanced finite element models of Mark III CCS plate is generated and used in conjunction with ultimate strength based failure criteria from laminated composite mechanics for the strength assessment. The strength assessment is performed within the initial failure state of Mark III CCS plate. Results provide failure details such as failure locations and loads. Finally obtained results are reviewed using the loads from acceptance criteria suggested by classification.
Identification of Whipping Response using Wavelet Cross-Correlation
Kim, Yooil ; Kim, Jung-Hyun ; Kim, Yonghwan ;
Journal of the Society of Naval Architects of Korea, volume 51, issue 2, 2014, Pages 122~129
DOI : 10.3744/SNAK.2014.51.2.122
Identification of the whipping response out of the combined wave-vibration response of a flexible sea going vessel is one of the most interesting research topic from ship designer`s point of view. In order to achieve this goal, a novel methodology based on the wavelet cross-correlation technique was proposed in this paper. The cross-correlation of the wavelet power spectrum averaged across the frequency axis was introduced to check the similarity between the combined wave-vibration response and impulse response. The calculated cross-correlation of the wavelet power spectrum was normalized by the auto-correlation of the each spectrum with zero time lag, eventually providing the cross-correlation coefficient that stays between 0 and 1, precisely indicating the existence of the impulse response buried in the combined wave-vibration response. Additionally, the weight function was introduced while calculating the cross-correlation of the two spectrums in order to filter out the signal of lower frequency so that the accuracy of the similarity check becomes as high as possible. The validity of the proposed methodology was checked through the application to the artificially generated ideal combined wave-vibration signal, together with the more realistic signal obtained by running 3D hydroelasticity program WISH-Flex. The correspondence of the identified whipping instances between the results, one from the proposed method and the other from the calculated slamming modal force, was excellent.
A Development of an Integrated Inventory Managing System for Steel-Plates
Lee, Seok Hyun ; Yu, Ji Hun ; Kim, Hyun Chul ; Jang, Seok Min ; Lim, Rae Soo ; Kim, Ho Kyeong ; Heo, Joo Ho ;
Journal of the Society of Naval Architects of Korea, volume 51, issue 2, 2014, Pages 130~137
DOI : 10.3744/SNAK.2014.51.2.130
As one of the largest shipbuilding company in the world, STX Offshore & Shipbuilding currently developed an inventory managing system for steel-plates, which is applied to their steel stock yard. In a traditional way to manage steel yard, almost every work has been done by manually. The manual steel-plate piling process caused some problems such as process delay due to piling errors and the uncertainty of work plan due to lack of information. To solve these problems, we developed an integrated inventory managing system based on real-time crane tracking system which automatically updates steel-plates` piling status. We built the integrated steel-plate database, developed several programs including steel-plate input program, real-time steel-plate monitoring program and steel-yard management program, and constructed hardware system for tracking magnetic cranes. As a result, a supervisor of steel-yard can manage the inventory of steel-plates efficiently and furthermore plan an efficient piling schedule and crane working schedule.
Study on the Application of an Expert System to Arrangement Design of Submarine
Kim, Ki-Su ; Ha, Sol ; Ku, Namkug ; Roh, Myung-Il ;
Journal of the Society of Naval Architects of Korea, volume 51, issue 2, 2014, Pages 138~147
DOI : 10.3744/SNAK.2014.51.2.138
This paper proposed an application of expert system to submarine arrangement design. Since all components of the submarine should be placed in a restricted place called pressure hull, expert knowledge has great effects on design of submarine arrangement. In this regard, a suitable knowledge-based expert system shell was applied to design of submarine arrangement process. To use expert system on the design of submarine arrangement effectively, a template model for submarine arrangement, which is proper to use in optimum design process, was developed. The proposed system was applied to simplified example of submarine arrangement problem to choose optimal design alternative. From this study, it was verified that expert system could be used in design of submarine arrangement with effect.
An Algorithm for Automatic Determination and Calculation of Volumetric Spaces of Submerged Bodies
Park, Inha ; Nam, Jong-Ho ;
Journal of the Society of Naval Architects of Korea, volume 51, issue 2, 2014, Pages 148~153
DOI : 10.3744/SNAK.2014.51.2.148
Submerged bodies such as autonomous underwater vehicles (AUV) or remotely operated vehicles (ROV) are widely used in various fields of exploring underseas. Those bodies keep ballasting and deballasting for stable navigation and operation. Identifying the internal volumetric spaces of the bodies is a primary step for such an operation. Unfortunately, most CAD models given to the engineer do not properly represent the compartments since each face of a compartment exists as an independent entity rather than as a face that belongs to the compartment. In this paper, an algorithm that automatically identify the faces as a group that forms a closed volumetric space, i.e., a compartment is presented. A submerged body is sliced into a number of cross sections. Each sliced section is analyzed to yield closed loops that are sections of the compartment. Then, the associated closed loops are gathered along the longitudinal direction to form a compartment. The algorithm presented is shown to provide a practical and reasonable solution that can readily be used in various applications.
The Effect of Hull Appendages on Maneuverability of Naval Ship by Sensitivity Analysis
Kim, Dae Hyuk ; Rhee, Key-Pyo ; Kim, Nakwan ;
Journal of the Society of Naval Architects of Korea, volume 51, issue 2, 2014, Pages 154~161
DOI : 10.3744/SNAK.2014.51.2.154
Naval ships have hull appendages which are more exposed to the outside because of its small block coefficient compared with commercial ships. These exposed hull appendages like skeg, strut and shaft line affect the maneuverability of a ship. The effect of hull appendages has considered at initial design stage to estimate more accurate maneuverability. In this paper, sensitivity analysis is used to analyze the effect on maneuverability by hull appendages. 3 DOF maneuvering equations based on Mathematical Modelling Group (MMG) model are used and propeller & rudder model are modified to reflect the characteristics of twin propeller & twin rudder. Numerical maneuvering simulations (Turning test, Zig-zag test) for benchmark naval vessel, David Taylor Model Basin (DTMB) 5415 are performed. In every simulation, it is calculated that stability indices and maneuverability characteristics (Tactical Dia., Advance, 1st Overshoot, Time of complete cycle) with respect to the parameters (area times lift coefficient slope, attachment location) of hull appendages. As a result, two regression formulas are established. One is the relation of maneuverability characteristics and stability indices and the other is the relation of stability indices and hull appendages.
Fully Unstructured Mesh based Computation of Viscous Flow around Marine Propellers
Kim, Min-Geon ; Ahn, Hyung Taek ; Lee, Jin-Tae ; Lee, Hong-Gi ;
Journal of the Society of Naval Architects of Korea, volume 51, issue 2, 2014, Pages 162~170
DOI : 10.3744/SNAK.2014.51.2.162
A CFD(Computational Fluid Dynamics) analysis is presented to predict hydrodynamic characteristics of a marine propeller. A commercial RANS(Reynolds Averaged Navier-Stokes equation) solver, namely FLUENT, is utilized in conjunction with fully unstructured meshes around rotating propeller. Mesh generation process is greatly accelerated by using fully unstructured meshes composed of both isotropic and anisotropic tetrahedral elements. The anisotropic tetrahedral elements were used in the flow domain near the blade and shaft, where the viscous effect is important, having complex shape yet resolving the thin boundary layers. For other regions, isotropic tetrahedral elements are utilized. Two different approaches simulating rotational effect of the propeller are employed, namely Moving reference frame technique for steady simulation, and Sliding mesh technique for unsteady simulation. Both approaches are applied to the propeller open water (POW) test simulation. The current results, which are thrust and torque coefficients, are compared with available experimental data.
Propeller Wake Measurement of a Model Ship in Self Propulsion Condition using Towed Underwater PIV
Seo, Jeonghwa ; Yoo, Geuk Sang ; Lim, Tae Gu ; Seol, Dong Myung ; Han, Bum Woo ; Rhee, Shin Hyung ;
Journal of the Society of Naval Architects of Korea, volume 51, issue 2, 2014, Pages 171~177
DOI : 10.3744/SNAK.2014.51.2.171
A two-dimensional particle image velocimetry (2D PIV) system in a towing tank is employed to measure a wake field of a very large crude oil carrier model with rotating propeller in self propulsion condition, to identify characteristics of wake of a propeller working behind a ship. Phase-averaged and time-averaged flow fields are measured for a horizontal plane. Scale ratio of the model ship is 1/100 and Froude number is 0.142. By phase-averaging technique, trajectories of tip vortex and hub vortex are identified and characteristic secondary vortex distribution is observed in the hub vortex region. Propeller wake on the starboard side is more accelerated than that on the port side, due to the difference of inflow of propeller blades. The hub vortex trajectory tends to face the port side. With the fluctuation part of the phase-averaged velocity field, turbulent kinetic energy (TKE) is also derived. In the center of tip vortex and hub vortex region, high TKE concentration is observed. In addition, a time-averaged vector field is also measured and compared with phase-averaged vector field.