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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 33, Issue 4 - Nov 1996
Volume 33, Issue 3 - Aug 1996
Volume 33, Issue 2 - May 1996
Volume 33, Issue 1 - Feb 1996
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Prediction of Unsteady Performance of a Propeller by Using Potential-Based Panel Method
I.S. Moon ; Y.G. Kim ; C.S. Lee ;
Journal of the Society of Naval Architects of Korea, volume 33, issue 1, 1996, Pages 9~18
This paper describes a potential-based panel method for the prediction of unsteady performance of a marine propeller operating in a non-uniform flow field. Boundary-value problem, formulated by distributing the normal dipoles and sources on the blade, the hub and the shed wake, is descretized and numerically analyzed in a discretized time domain. Through an extensive test and comparison with the analytic solution, the convergence in time step is verified for a two-dimensional foil. Unsteaty analysis is then carried out for the DTRC 4118 propeller operating in a harmonic wake, and compared favorably with the experimental result. The present method is shown applicable to the analysis of unsteady performance of the propellers.
A Study of a Correlation between Experiments and Calculations of Pressure Fluctuation on Hull Surface
Moon-Chan Kim ; Ki-Sup Kim ; In-Haeng Song ;
Journal of the Society of Naval Architects of Korea, volume 33, issue 1, 1996, Pages 19~26
An experimental and computational study of the pressure fluctuation induced by a propeller on a hull surface was carried out with three ship models and seven model propellers. The fluctuation of pressure on a flat plate was measured at KRISO cavitation tunnel and calculated by a panel and lifting surface method(XForShip code). To extend the measurement data on the flat plate into that on complex hull forms, the correction factor was determined as a ratio of the solid boundary factor(SBF). The computation of pressure fluctuation around complex hull forms was also performed to make the full scale prediction and compared with the corrected experimental data. The calculated values agreed well with the compensated experimental data and it was found that the correction factor was about 0.65-0.7.
On the Variation of Resistance Components due to Air Bubble Blowing on Bulb Surface of a Ship
Geun-Tae Yim ; Hyo-Chul Kim ;
Journal of the Society of Naval Architects of Korea, volume 33, issue 1, 1996, Pages 54~64
It seems that blowing air bubble out of the bulb surface of a ship of flat bottom will reduce the frictional resistance, since wetted area of the hull surface is reduced owing to air bubble staying close to the surface. To as certain this concept, at first, the limiting streamlines around the bow was observed, and local distribution of pressure and shear stress, due to the change of air-blowing position, air supply pressure, and the model speed, was investigated. It was found that the local friction was reduced near the bulb and air-bubble formations also play an important role as a drag component. This paper can be considered as a preliminary study on the drag reduction of conventional ships by the micro-bubble injection.
A Structural Design Expert System with Integrated Design Environments
K.H. Lee ; D.K. Lee ;
Journal of the Society of Naval Architects of Korea, volume 33, issue 1, 1996, Pages 135~144
In this article, an Expert System for MIDship section design(ESMID) is developed based on a general-purpose expert system shell. The system focuses on the integration of knowledge-based system and design resources such as an engineering database, graphical user interface, and engineering application program for the calculation of section modulus and longitudinal strength of ship structure. The validation of the ESMID system was examined and verified by applying the system to the 64K bulk carrier. The developed expert system can help a novice engineer in designing the midship section of ship.
Preliminary Design of a Ship by the Knowledge-Based Optimum Design System
Dong-Kon Lee ; Soo-Young Kim ;
Journal of the Society of Naval Architects of Korea, volume 33, issue 1, 1996, Pages 161~172
Although conventional computer programs use efficient and precise optimization algorithms, they can not emulate the problem solving capabilities of human experts. A design optimization process involves a number of tasks which require human expertise and experience. Traditional optimization systems have concentrated on numerical aspects of a design process and have not been successful in integrating the numerical parts with human expertise. On the other hand, most knowledge-based systems focus on symbolic reasoning and have been little concerned with the numerical processes. The objective of this paper is to develop a knowledge-based multiobjective optimum design system which has the capabilities of knowledge processing and numerical computation by integrating the multiobjective optimization method and the knowledge-based system. The knowledge-based system for symbolic processing is developed. Rules for knowledge representation and the inference mechanism of the system are written in LISP. The knowledge-based multiobjective optimum design system is finally developed by integrating the multiobjective optimization method and the knowledge-based system by applying shell programming technique. The system is applied to an optimum design model of a LNG carrier in the preliminary design stage. It is found that the system well simulate design variables and objective functions of the design model.