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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 36, Issue 4 - Nov 1999
Volume 36, Issue 3 - Aug 1999
Volume 36, Issue 2 - May 1999
Volume 36, Issue 1 - Feb 1999
Selecting the target year
Stability Analysis of a Small Racing Boat in Steady Wind and Wave Impact
S.H. Chun ; H.H. Chun ; M.K. Ha ; M. Nakato ;
Journal of the Society of Naval Architects of Korea, volume 36, issue 1, 1999, Pages 1~14
The simulation results of a small racing boat racing in steady wind and encountering waves are investigated by Nakato & Ha. The simulation of the race running is realized by referring the measured data of boats and the motions are described by a set of equations of motion in six degree of freedom as generals used in the aerodynamics. In this report, Nakato & Ha's motion equations are modified by equipping the flaps to generate the lift. The flaps of the racing boat could restrain considerably the boat from capsizing caused by superposed external disturbances, wind and encountering waves.
Test for Local Structural Identifiability of Linear Equations of Motion for Submergibles
Chan-Ki Kim ;
Journal of the Society of Naval Architects of Korea, volume 36, issue 1, 1999, Pages 15~21
In this paper, the issue of local structural identifiability of linear equations of motion with non-linear parametrizations is discussed. The test method is resented that provides analytical expressions for information matrices of which the rack determines identifiability. And this method is applied to investigate local structural identifiability of linear equations of motion for a submergible vehicle. As a result, it is showed that with given parameters, the linear equations of motion do not satisfy the definition of local identifiabiliy according Glover & Willems.
Experimental Study on the Effects of Water Jetting on a Flapped Rudder
Hae-Seong Ahn ; Hyo-Chul Kim ;
Journal of the Society of Naval Architects of Korea, volume 36, issue 1, 1999, Pages 22~29
In the development of high speed marine vehicle, lilting devices became important in sharing the pay load or controlling the attitude. The devices are also important to meet the IMO regulation to prevent the marine pollution by keeping the high rudder force for VLCC even in low speed operation. The high lift devices such as the Coanda device have been introduced to the aircraft as a common practice for a long time among the aero-engineers. If the Coanda device can be utilized to the flapped rudder, the severe requirement of rudder force could be provided for the VLCC in low speed operation. The performance of the rudder system has been investigated at the towing tank of Seoul National University.
Steady/Unsteady Analysis of Ducted Propellers by Using a Surface Panel Method
Kwang Kim ; Sang-Woo Pyo ; Jung-Chun Suh ;
Journal of the Society of Naval Architects of Korea, volume 36, issue 1, 1999, Pages 30~36
A surface panel method for the analysis of ducted propellers in both uniform and non-uniform onset inflow is developed. A low order, perturbation potential based panel method with an efficient numerical Kutta condition is used. The boundary surface is discretized with hyperboloidal panels and the boundary condition is applied at the panel centroids. The unsteady analysis is based on a time-step algorithm in time domain. Numerical implementation is employed into both steady and unsteady problems. The results with the resent method are shown to have good convergence on the circumferential distribution of circulation on the duct. The effect of the propeller tip clearance on the circumferential circulation on the duct is also presented Numerical results on forces and moments of the propeller and the duct are compared with other numerical results and experimental data.
Inception of Tip Vortex Cavitation on Ducted Rotors
K.S. Kim ; K.Y. Kim ; J.W. Ahn ; J.T. Lee ; E.D. Park ; H.B. Chae ; H.S. Lee ;
Journal of the Society of Naval Architects of Korea, volume 36, issue 1, 1999, Pages 37~46
The influence of the tip clearance upon the cavitation inception were investigated by experiments for ducted rotors having different tip clearances The axial and tangential mean velocities around the ducted rotors were measured using an L.D.V. system to investigate the correlation between tip vertex cavitation inception and hub vortex cavitation. Observation results for tip vortex cavitation and hub vortex cavitation show good agreement in trend with the analysis results of velocity measurement. An optimum tip clearance for ducted rotor was selected to delay the tip vortex cavitation.
An experimental study for prediction of the fluctuating pressure induced by a cavitating propeller
K.S. Kim ; I.S. Moon ; K.Y. Kim ; I.H. Song ; J.T. Lee ;
Journal of the Society of Naval Architects of Korea, volume 36, issue 1, 1999, Pages 47~52
The influence of propeller revolution on measurement of fluctuating pressure is almost minimized in the KRISO cavitation tunnel and the measurement accuracy of fluctuating pressure acting on a flat plate due to a cavitating propeller is improved. The measurement data for Sydney Excess propeller is compared with the measurement results of other research institutes loading to the conclusion that KRISO data is so stable and reasonable. The fluctuating pressure data measured on a model ship and the prototype ship is compared with the data measured on the flat plate. The solid boundary factor, derived from a calculation based on a lifting surface theory, is applied to predict full scale pressure level from the experimental data on the flat plate, showing quite reasonable agreement with full scale data.
A Study of Propeller Thrust in Dock Trials
K.N. Chung ; J.C. Won ; H.W. Seo ; G.I. Choi ;
Journal of the Society of Naval Architects of Korea, volume 36, issue 1, 1999, Pages 53~60
Prior to sea trials, dock trials are usually carried out in order to check the main propulsion system and auxiliaries. At that time the motion of a ship is limited by mooring ropes. In Hyundai Heavy Industries, a simple equation is used to obtain propeller thrust which is used as an input data of mooring analysis. Recently the ship size and the engine power become larger. Therefore a careful analysis of the mooring condition is necessary in order to avoid possible accidents. In this study propeller thrust at deck trials is reviewed and examined through a series of model tests.
Practical Method for Generating Surface Mesh using Offset Table
Wo-Joan Kim ; Suak-Ho Van ;
Journal of the Society of Naval Architects of Korea, volume 36, issue 1, 1999, Pages 61~69
To promote the usability of CFD techniques for the basic hull form design, a hull surface mesh generating program, based on given station offsets and centerline profile, is developed. The new method employs non-uniform parametric splines with predetermined waterline end-shapes of natural spline, normal spline, ellipse, parabola hyperbola, and their combinations. Generated hull surface meshes can be utilized for potential panel method immediately and can be also used as a boundary grid surface for 3-D field grid system. Mesh topology chosen to represent hull surface can be transformed into a rectangle, which he1ps the flow solvers to transform surface meshes for the nonlinear free surface condition or to define the turbulence quantities. To prove the applicability, a container ship with bow and stem bulb is chosen, and the procedures generating hull surface meshes are described.
Development of 3-D Field Grid Generating Method for Viscous Flow Calculation around a Practical Hull Form
Wu-Joan Kim ; Do-Hyun Kim ; Suak-Ho Van ;
Journal of the Society of Naval Architects of Korea, volume 36, issue 1, 1999, Pages 70~81
To predict the viscous boundary layers and wakes around a ship, the CFD techniques are commonly used. For the efficient application of CFD tools to practical hull farms, a 3-D field grid generating system is developed. The present grid generating system utilizes the solution of Poisson equation. Sorenson's method developed for 2-D is extended into 3-D to provide the forcing functions controling grid interval and orthogonality on hull surface, etc. The weighting function scheme is used for the discretization of the Poisson equation and the linear equations are solved by using MSIP salver. The trans-finite interpolation is also employed to assure the smooth transition into boundary surface grids. To rove the applicability, the field grid systems around a container ship and a VLCC with bow and stem bulb are illustrated, and the procedures for generating 3-D field grid system are explained
Optimum Structural Design Using AHP Technique
Young-Soon Yang ; Beom-Seon Jang ;
Journal of the Society of Naval Architects of Korea, volume 36, issue 1, 1999, Pages 82~89
A designer must make a lot of decisions in a design process. The decisions may be classified into selection decisions and compromise decisions. As the results of two decisions depends on the designer's intention it is necessary that the designer's intention should be reflected in the design systematically and precisely. As the AHP(Analytic Hierarchy Process) technique analyzes and evaluates a obscure selection problem hierarchically, designer's intention can be reflected in the design systematically. Also as qualitative attributes can be rated at quantitative criterion the designer's intention can be reflected consistently. Usually an engineering problem is a coupled problem in which a designer must select one alternative from a set of alternatives and find optimal characteristics of the alternative concurrently. As considered attributes are functions of the compromise system variables and the attributes's units and orders are different each other, attribute ratings must be normalized. This paper introduces a neural network at this normalization. So the attribute ratings can reflect designer's intention and the knowledge from his(her) experience automatically.
Optimum Design of Viscoelastic Layered Beam to Minimize Flexural Vibration
Sa-Soo Kim ; Dae-Seung Cho ; Min-Woo Lee ;
Journal of the Society of Naval Architects of Korea, volume 36, issue 1, 1999, Pages 90~98
For the control of vibration and noise of metal structures having relatively low damping, viscoelastic materials are widely used and usually attached at metal structures with an additional constraining layer to secure them. The damping and elastic properties of structures having constrained viscoelastic material layers are dependent on not only temperature and frequency but also their thicknesses. Hence, optimal design of the thicknesses of viscoelastic and constraining layers for a certain base structure are very important to maximize their efficiency and to lighten their weight. In this study, the variation of loss factor of beams having a constrained viscoelastic layer according to the change of thickness has been carefully investigated. From these, optimal design method of the minimum thickness beam having a given loss factor is suggested and numerically verified for a real beam.
A Study on Very High-rise Steel Artificial Reefs Based on Computer Graphics - part I (Design Aided Program Development)
Hyun-Kyoung Shin ; Ho-Gyun Park ;
Journal of the Society of Naval Architects of Korea, volume 36, issue 1, 1999, Pages 99~108
The solid modelling program was developed for the 3-D representation and analysis of VEry High-rise Steel Artificial Reefs(VEHSAR) using Visual C++ on the Microsoft's Windows 95(or Windows NT) based on MFC(Microsoft Foundation Class). Importing oriented-object program and CAD/CAM technique, this integrated design system which aims at low cost and high efficiency makes it possible to predict problems and to establish counterplans through visualizing the construction of Very High-rise Steel Artificial Reefs in advance. Also it is useful in enhancing productivity. Introduction of OpenGL makes it display high quality 3D graphics more faster.