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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 38, Issue 4 - Nov 2001
Volume 38, Issue 3 - Aug 2001
Volume 38, Issue 2 - May 2001
Volume 38, Issue 1 - Feb 2001
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Computation of Turbulent Flow around a Ship Model with Free-Surface
Jung-Joong Kim ; Hyoung-Tae Kim ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 1, 2001, Pages 1~8
The computations of the turbulent flow around the ship models with the free-surface effects were carried out. Incompressible Reynolds-Averaged Navier-Stokes equations were solved by using an explicit finite-difference method with the nonstaggered grid system. The method employed second-order finite differences for the spatial discretization and a four-stage Runge-Kutta scheme for the temporal integration. For the turbulence closure, a modified Baldwin-Lomax model was exploited. The location of the free surface was determined by solving the equation of the kinematic free-surface condition using the Lax-Wendroff scheme and a free-surface conforming grid was generated at each time step so that one of the grid boundary surfaces always coincides with the free surface. An inviscid approximation of the dynamic free-surface boundary condition was applied as the boundary conditions for the velocity and pressure on the free surface. To validate the computational method developed in the present study, the computations were carried out for beth Wigley and Series 60
ship model and the computational results showed good agreements with the experimental data.
A Study on the Flow Characteristics around a Hull Form of Coast-Canal Going Pusher-Barge
Sung-Yong Kim ; Young-Gill Lee ; Seung-Hee Lee ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 1, 2001, Pages 9~26
In this paper. the development of a pusher-barge hull form which enables the continuous transportation along the coast and canal is performed. For the design stage of the hull forms. these are developed for Kyungin canal which is will be drawn up as the next contribution project of the Korean government are adopted. The model tests for the designed ship are carried out in the Inha University Towing Tank and the numerical simulations are done with a finite difference method based on MAC scheme. At first, the experiments are performed with designed model ships from low speed to high speed including service speed(6knots) among the corresponding designed speed. Resistance characteristics of designed ships are compared with experimental results of other several pusher-barge hull shapes. Next, the numerical simulations are performed for three cases, that is pusher only, barge only and pusher-barge condition in the designed speed. Each calculations are carried out in deep and restricted water condition. The flow characteristics around hulls in the latter condition are compared with those in the former condition.
On the Transportation Efficiency of Barge System in Kyongin Canal
J.W. Lee ; Y.H. Kim ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 1, 2001, Pages 27~36
Recently, the coastal transportation of the Yellow Sea is increasing due to the vastly expanding trade among countries surrounding the Yellow Sea. As the 50 percentages of the total domestic container transportation are concentrated on the National Capital region, the traffic congestion in the key land transportation routes brings about the weakening of the global competitiveness. In this study, the efficient barge systems for sea-river shipping of the Han-river, the Kyongin canal and coastal ways of the Yellow Sea are considered based on the criterion of canal and cargo volumes. To find the efficient barge system of the model barge in the Kyongin canal. the transport efficiency factor and transport ability of each barge system with the variation of sailing speed and length are calculated.
An Experimental Study on Development of the Wave Absorber for Small Wave Flume
H.S. Lee ; S.H. Kwon ; H.J. Jo ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 1, 2001, Pages 37~42
This paper proposes a new wave absorber made of flexible net structures. The motivation of this research is that the wave absorbers which already invented are not effective in small wave flume. To test the efficiency of the proposed water absorber, experiments were done for various wave length, the length of the wave absorber, and the areas of the wave absorber. The proposed new wave absorber demonstrated its efficiency when used in small-length wave flume.
Computation of the Hydrodynamic Coefficients of Ships in Waves by Rankine Source Panel Methods
Jin-Ho Yang ; Ki-Jong Song ; Ho-Hwan Chun ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 1, 2001, Pages 43~51
The unsteady problems of ships in waves are analyzed by a low order panel method with Rankine source. Considering the basic flow as the uniform incoming flow(so called Kelvin flow) and also the double body flow. the solutions to satisfy the governing equation with the boundary conditions are obtained, and these two results are compared. The hydrodynamic coefficients for the modified Wigley hull and Series 60(
) are computed and compared with the experimental data available and also other computational results published. It is shown that the computational results by the double body approximation agree well with the experimental results compared with those by the uniform Kelvin flow approximation.
An Experimental Study on Stern Flow around a VLCC model with Drift Angles
Wu-Joan Kim ; Do-Hyun Kim ; Yeon-Gyu Kim ; Sun-Young Kim ; Suak-Ho Van ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 1, 2001, Pages 52~61
It is necessary to obtain the well-documented local flow measurement data for the validation of CFD prediction of hydrodynamic performance. In the present paper the local flow fields around the stern region of a VLCC model with drift angles of
are measured. Mean velocity components are documented at St. 2 and A.P. of both port and starboard side of KVLCC in KRlSO towing tank. Flow information associated with the formation of four discrete vortices in the stern region is explored. The present experimental data can provide a good test case to validate the accuracy of numerical modeling for stern flow and maneuverability prediction of modern tanker hull forms.
Computation of RCS and TES of Curved Objects Using a Curved-Patch Physical Optics Method
Sung-Youn Boo ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 1, 2001, Pages 62~71
Prediction of ship's signature of RCS(Radar Cross Section) and TES(Target Echo Strength) is mostly required in the initial design stage of naval craft, because RCS is directly related to the radar detection while TES to the sonar detection. In this research, a numerical scheme using a curved-patch physical optics method is proposed to evaluate signature of a perfectly reflecting curved object. The scheme is validated by comparing numerical RCS values of circular cylinder, sphere and NACA3317 airfoil with available data. It is also further applied to predict RCS of a surfaced submarine and TES of fully submerged one. Major reflectors of the surfaced or submerged submarine for the various incident angles of radar and sonar waves are investigated as well.
Strength Evaluation of a Doubler Plate of Ship Structure subjected to the Biaxial In-plane Compression
Juh-Hyeok Ham ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 1, 2001, Pages 72~85
A study for the structural strength evaluation on the doubler plate subjected to the biaxial in-plane compression has been performed through the systematic evaluation process. In order to estimate the proper static strength of doubler plate, elasto-plastic large deflection analysis is introduced including the contact effect between main plate and doubler. The characteristics of stiffness and strength variation are discussed based on their results. A1so, in order to compare the doubler structure with the original strength of main plate without doubler, a simple formula for the evaluation of the equivalent flat plate thickness is derived based on the additional series analysis of flat plate structure. Using this derived equation, the thickness change of a equivalent flat plate is analyzed according to the variation of various design parameters of doubler plate and some design guides are suggested in order to maintain the original strength of main plate without doubler reinforcement. Finally, correlation between derived equivalent flat plate formula and the developed buckling strength formulas by author et a1. is discovered and these relations are formulated for the future development of simple strength evaluation formula of doubler plate structure.
Development of the Design System for the Lifting Lug Structure
Juh-Hyeok Ham ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 1, 2001, Pages 86~98
Due to the rapid growth of ship building industry and the increment of ship construction in Korea, several hundred thousand of lifting lugs per year, have been installed at the lifting positions of ship block and removed after finishing their function, therefore. appropriate design system for the strength check or the optimal design of each lug structure has been required in order to increase the capability of efficient design. In this study, the design system of D-type lifting lug structure which is most popular and useful in shipyards, was developed for the purpose of initial design of lug structure. Developed system layout and graphic user interface for this design system based on the
language were explained step by step. Through the illustration of one example of D-type lug designs, the efficiency of this design system was proved. Therefore, more efficient performance of practical lug structural design will be expected on the windows of personal computer using this design system.
The examination of application possibility and development of new welding joint shape for aluminum alloy
Jong-Myung Kim ; Chong-In Oh ; Han-Sur Bang ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 1, 2001, Pages 99~107
Manufacture of fishing vessel is needed the effective material for light, strength, fire and corrosion of water in order to improve durability by high-speed and fishing. These fishing vessel can be divided into FRP and AI alloys fishing vessel. FRP fishing vessel is light and effective for strength but highly ignited and susceptible to heat during the manufacturing ship by-produce noxious component for human. In the case of a scrapped ship, it cause environmental pollution. On the other hand, aluminum is a material in return for FRP and has merit of high-strength and lightness. It's more heat proof and durable than FRP and superior to prevent from corrosion. Al alloys fishing vessel development is rising as an urgent matter. But, al alloy has some defect of bad weldability, welding transformation, cracks and overcost of construction. Therefore this study is to develop the new welding joint shape solving aluminum defects and mechanical behavior. First of all, strength was compared and reviewed by analysis of plate, stiffen plate, new model simplified by using plate theory. On the base of this result, plate and new model of temperature distribution, weld residual stress and strength of tensile, compressive force were compared and reviewed by finite element computer program has been developed to deal with heat conduction and thermal elasto plastic problem. Also, new model is proved application possibility and excellent mechanic by strength comparison is established to tensile testing result.
An experimental study on the performance of silencers for exhaust merchant ships considering air flow velocity
Jae-Kwang Eom ; Sa-Soo Kim ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 1, 2001, Pages 108~115
The noise level of the navigation bridge as well as topside of the superstructure is dominated by the exhaust gas noise of the high-powered main engine and generator engine of special purpose vessels. In the case of the noise radiated from the top of the funnel. the exhaust pipe can be fitted with a silencer to reduce the propagated noise level. This paper is prepared based on an experimental performance test results of the silencers for generator-engine exhaust gas noise with consideration of air velocity. Two silencers were examined to check the performance of noise reduction in cases of air velocity 0m/s and 32m/s. In the sound reduction test, 400mm and 600mm diameter pipe ducts equipped with an axial fan were used as exhaust gas pipe system in the actual ship. The test procedure and results are presented in detail.
A Study on the Fire Safety Assessment of a Ship
Jung-Hoon Lee ; Jae-Ohk Lee ; Young-Soon Yang ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 1, 2001, Pages 116~122
In this paper, to make a base of the fire safety assessment about ship's fire protection design and Classification Society rule, statistical informations and modeling techniques for the fire safety engineering are investigated and probabilistic safety assessment methods in the structural reliability engineering are introduced. FSEM(Fire Safety Evaluation Module) developed in this paper calculates the probability of fatality, which can be used as an index of fire safety. FSEM is used to calculate the probability of fatality of the evacuees in a small room installed according to the rules for fire-proof. Sensitivity analysis is executed to investigate FSEM's applicability to ship. From results, the necessity of new criterion for ship's fire safety design, the need to study the human behavior in the evacuation from fire, and the development of new fire progress model considering special situations in ships are acknowledged.