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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 43, Issue 6 - Dec 2006
Volume 43, Issue 5 - Oct 2006
Volume 43, Issue 4 - Aug 2006
Volume 43, Issue 3 - Jun 2006
Volume 43, Issue 2 - Apr 2006
Volume 43, Issue 1 - Feb 2006
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A Numerical Study on the Coupled Dynamics of Ship and Flooding Water
Hong, Sa-Young ; Kim, Jin ; Park, Il-Ryong ; Choi, Seok-Kyu ;
Journal of the Society of Naval Architects of Korea, volume 43, issue 6, 2006, Pages 631~637
DOI : 10.3744/SNAK.2006.43.6.631
This paper presents a numerical method to solve the ship motion coupled with internal fluid flow. Physically the internal fluid motion is coupled with the ship motion. Hitherto the previous numerical results of the coupled motion predict only the general tendency with experiments. The main reason of inaccuracy is that the coupled dynamics of ship motion and internal water motion is not accurately accounted. In this study CFD technique based on VOF is employed for the accurate analysis of flooding water motion. Some cases of the 24th ITTC stability committee's benchmark.study for tanker with internal fluid are analyzed by coupling the ship motion and sloshing dynamics. The calculated ship motion is compared with the experimental result to validate the coupled scheme and is in agreement with the experimental result.
Panel Cutting Method a New Approach in Hull Surface Panel Generation
Kim, Jin ; Van, Suak-Ho ; Park, Il-Ryong ; Kim, Kwang-Soo ; Choi, Hee-Jong ;
Journal of the Society of Naval Architects of Korea, volume 43, issue 6, 2006, Pages 638~646
DOI : 10.3744/SNAK.2006.43.6.638
In this paper a new hull-panel generation algorithm named 'Panel Cutting Method' was developed to solve the flow phenomena around a ship advancing on the free surface with a constant speed. In this algorithm the non-linearity of the free surface boundary conditions was taken into account using the iterative method and the raised panel was used at each iteration step. Numerical calculations were performed to investigate the validity of the developed algorithm using the series
hull The wave resistance coefficients, the wave patterns and the wave heights were compared between the computed and the experimental results at Fn=0.25 and 0.316. The comparison showed good agreement between computation and experiment.
On the Vertical Plane Dynamics Modeling and Depth Control of a Submerged Body Moving beneath Free Surface
Yeo, Dong-Jin ; Rhee, Key-Pyo ; Park, Jeong-Yong ; Choi, Ju-Hyuck ;
Journal of the Society of Naval Architects of Korea, volume 43, issue 6, 2006, Pages 647~655
DOI : 10.3744/SNAK.2006.43.6.647
In this paper, submerged body dynamics model in vertical plane which can include the effect of free surface and wave is suggested to simulate the motions of submerged body moving beneath free surface precisely. A controller is designed, which can maintain a constant depth below the mean sea level and minimize the pitch angle. Numerical simulations show that the designed controller is effective on depth keeping and minimizing pitch angle in regular waves and irregular waves.
Research of Elements Giving Effects on the Numerical Analysis for the LNG Carrier
Kim, Hee-Taek ; Kim, Hyoung-Tae ;
Journal of the Society of Naval Architects of Korea, volume 43, issue 6, 2006, Pages 656~666
DOI : 10.3744/SNAK.2006.43.6.656
Numerical analysis using the FLUENT is performed for the 138K LNG carrier of the MOERI. In this study, results according to the number and also the type of the grid, different turbulent models, variations of y+ are compared with experiments and computational results from the WAVIS. RSM model gives good result in comparison with other models, and the more the number of grid increase, the better the resistance converges to the constant value. Additionally, it is confirmed that the resistance and wake distributions vary with the change of y+, and O-O type grid yields better wake distributions than that of O-H type. Average velocity distributions and velocity profiles are mainly in accord with experiments and computational results of the WAVIS, however, present results in the region of transom and tip of leading edge of the rudder are poor for the lower velocity components comparing with that of the WAVIS.
A RANS-based Simulation for the Prediction of Hydrodynamic Rolling Moments around Rectangular Cylinders with Free Surface
Kim, Su-Whan ; Kim, Kwang-Soo ; Park, Il-Ryong ; Van, Suak-Ho ; Kim, Jin ;
Journal of the Society of Naval Architects of Korea, volume 43, issue 6, 2006, Pages 667~674
DOI : 10.3744/SNAK.2006.43.6.667
Accurate prediction of ship dynamics, particularly roll motion, is very important in ship safety. In the past, empirical or vortex based methods were commonly used for the hydrodynamic roll damping predictions but they could not be applied to practical ship roll motion cause of limitations about geometries ad design conditions. Recently RANS-based techniques are developed for the practical ship motion analysis. In this study, RANS based roil analysis about a rectangular cylinder with WAVIS developed by MOERI/KORDI are performed and compared with the experimental data and other RANS results.
Large Eddy Simulation of Turbulent flow around a Square Cylinder
Chun, Ho-Hwan ; Jung, Kwang-Hyo ; Yoon, Hyun-Sik ;
Journal of the Society of Naval Architects of Korea, volume 43, issue 6, 2006, Pages 675~682
DOI : 10.3744/SNAK.2006.43.6.675
This study has investigated the turbulent flow around a square cylinder by using LES (large eddy simulation). Numerical simulations are performed for turbulent flow fields with Re = 22,000. The computed results are in good agreement with existing computational and experimental data. The time-averaged and phase-averaged turbulent statistics around a square cylinder are discussed. Total 20 phase bins extracted from one cycle period showed detailed wake structures of the phase-averaged flow field. The center of Karman vortex sheets did not deviated
from centerline of square cylinder while moving downstream.
Application of Initial Stress Method on Elasto-plastic Problem in Boundary Element Method
Soo, Lyong-Lee ;
Journal of the Society of Naval Architects of Korea, volume 43, issue 6, 2006, Pages 683~692
DOI : 10.3744/SNAK.2006.43.6.683
The BEM, known as solving boundary value problems, could have some advantages In solving domain problems which are mostly solved by FEM and FDM. Lately, in the elastic-plastic nonlinear problems, BEM could provide the subdomain approach for the region where the plastic deformation could occur and the unknown nodal displacement of this region are added as the unknown of the boundary integral equation for this approach. In this paper, initial stress method was used to establish the formulation of such BEM approach. And a simple rectangular plate having a circular hole was analyzed to verify the suggested method and the result is compared with that from FEM. It is shown that the result of two methods are showing similar stress-strain curves at the root of perforated plate and furthermore the plastic deformation obtained by BEM shows more reasonable behavior than that of FEM.
A Study on Ship Shape Design Optimization for RCS Reduction Using Taguchi Method
Cho, Yong-Jin ; Park, Dong-Hoon ; Ahn, Jong-Woo ; Park, Cheol-Soo ;
Journal of the Society of Naval Architects of Korea, volume 43, issue 6, 2006, Pages 693~699
DOI : 10.3744/SNAK.2006.43.6.693
This paper proposes a design optimization technique for ship RCS signature reductions using Taguchi method. The proposed technique comprises of i)evaluating initial RCS signatures, ii)defining critical areas which should be modified as design parameters, and threat factors which can't be controlled artificially as noise parameters, and finally iv)finding optimum parameters via analyzing signal to noise ratios for designated characteristics. We applied the technique to a model ship and found that it is suitable for radar stealth designs. In addition, the proposed technique is applicable to submarine designs against sonar threats.
Development of Data Mining Tool for the Utilization of Shipbuilding Knowledge based on Genetic Programming
Lee, Kyung-Ho ; Park, Jong-Hoon ; Choi, Young-Bok ; Jang, Young-Hoon ; Oh, June ;
Journal of the Society of Naval Architects of Korea, volume 43, issue 6, 2006, Pages 700~706
DOI : 10.3744/SNAK.2006.43.6.700
As development of information technology, companies stress the need of knowledge management. Companies construct ERP system including knowledge management. But, it is not easy to formalize knowledge in organization. They experience that constructing information system help knowledge management. Now, we focus on engineering knowledge. Because engineering data contains experts' experience and know-how in its own, engineering knowledge is a treasure house of knowledge. Korean shipyards are leader of world shipbuilding industry. They have accumulated a store of knowledge and data. But, they don't have data mining tool to utilize accumulated data. This paper treats development of data mining tools for the utilization of shipbuilding knowledge based on genetic programming(GP).