• Journal of the Society of Naval Architects of Korea
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• v.58 no.1
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• pp.32-39
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• 2021

Korean coastal fishery suffers from profitability degradation due to a decrease in fisheries resources, pollution in coastal waters, fuel coast increase, and market opening for aquaculture products. The next generation Korean fishing vessel aims at the improvement of energy efficiency, enhancement of crew welfare, and safety. These purposes can be accomplished by adopting a new standard hull form with improved resistance performance and a modernized residence facility on the deck. In order to improve resistance performance, this study attempts to optimize design variables for stern flaps for three kinds of fishing vessels - coastal multi-purpose, coastal trap, and dredged nets. A series of model tests for these fishing vessels was carried out in the towing tank of Pusan National University. The results indicate that for some cases, the stern flap caused the stern trim of the vessel to decrease, leading to the resistance reduction.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.2
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• pp.76-85
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• 2023

The present study aims to review the wave pattern resistance analysis method suggested by the International Towing Tank Conference. From the experimental database of a container carrier ship model, the wave pattern measurement and resistance test results are utilized. The wave pattern resistance at the design Froude number is obtained to be compared with the wave making resistance of experiments. Wave pattern resistance is lower than wave making resistance by 1978 ITTC and uniform regardless of transverse location of wave cut. The method is also applied to the wave height field by Computational Fluid Dynamics (CFD) analyses with Froude number variation. Although numerical damping suppressed waves in downstream, waves around the hull and wave pattern resistance are properly predicted.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.579-585
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• 2019

Increasing the detection probability of underwater targets necessitates securing the towing stability of the active towed SONAR. In this paper, to confirm the effects of tail wing fin on towing attitude and towing stability, two scale model experiments and one sea trials were conducted and the results were analyzed. The scale model tests measured the towing behavior of each of the tail fin shapes according to towing speed in a towing tank. The shape of the tail fin used in the scale model test was tested with an I-type tail fine and four Y-type tail fins, totaling five tail fins of the two kinds. The first scale model test confirmed that the Y-type tail fin was superior to the I-type tail fin in towing attitude and towing stability. The second scale model test confirmed the characteristics of the vertical tail fin height increase and the lower horizontal tail fin inclination angle application shape based on the Y-type tail fin. The shape of the application of the lower horizontal tail fin inclination angle showed the best performance. In order to verify the results of the scale model test, a full size model was constructed, sea trials were performed, and the towing attitude was measured. The results were similar to those of the scale model test.

• Journal of Biosystems Engineering
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• v.13 no.4
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• pp.30-37
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• 1988

A mathematical model was developed and programmed for computer simulation of a prototype hot water boiler system with rice hull furnace to predict the temperature distributions in the rice hull furnace and water tank, mass flow rate of hot water and thermal efficiency of the system under various operation and design conditions. The effects of feed rate of rice hull, thickness of the furnace wall, the type of heat exchanger, diameter of the water circulation pipe, etc, on the performance of the system can be evaluated with this model. The validity and simulation results of this model will be published in the next paper.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.2
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• pp.44-52
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• 2001

A modeling program was developed in Part I which represents the 3-D geometry, produces bill of material, automatically draws drawings and produces input data for structural analysis of Very High-rise Steel Artificial Reefs(VEHSAR). Model tests were carried out to measure drag forces acted on VEHSAR in the Ocean Engineering Wide Tank, the University of Ulsan and structural analyses were made to simulate structural behaviors of VEHSAR. The integrated package system is suggested to design VEHSAR with different geometries.

• Journal of Ocean Engineering and Technology
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• v.16 no.3
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• pp.1-7
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• 2002

In this paper, a numerical model to analyze the performance of a vertical slit-type wave absorber is developed under the assumption of inviscid water waves. The formulation combines the linear potential theory with a semi-empirical description of the eddy-shedding at a slit-type wave absorber. We investigated the reflection coefficients over a wide frequency range for a vertical slit-type wave absorber both with and without a solid rear wall. Model test was conducted at KRISO' s two dimensional wave tank to validate the theoretical results. It is found that the agreement between theoretical results and experimental data is surprisingly good. We found that the wave absorbing system using a vertical slit plate has sufficient potentials for breakwaters for ocean development.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.4 no.3
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• pp.156-160
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• 1992

The evolution of leading waves generated by a wavemaker in a two-dimensional tank has been studied. The front of wave trains can be described in general by the Schrodinger equation. In particular, when the slope of the carrier waves is steep, and hence nonlinearity becomes important, the cubic Schrodinger equation is proved to be an appropriate mathematical model. Computations are made by using the Crank-Nicolson algorithm and compared with experimental data. It is found that the numerical result predicts the evolution of leading waves fairly well and the evolution is significantly affected by nonlinearity for steep waves when kh＞1.36.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.11a
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• pp.563-568
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• 2001

본 연구에서는 3차원 그래픽 시뮬레이션 게임 제작 연구를 목적으로 하여 3차원 그래픽 전차모델을 제작하고 이를 이용한 전차전 시뮬레이션 게임 제작을 목표로 한다. 게임 상에는 아군과 대항군의 2대의 전차가 사용되며 대항군 전차는 통계적인 함수 모형을 이용하여 자체적인 전투 수행을 할 수 있도록 하고, 아군 전차는 사용자가 움직임을 통제한다. 본 논문의 결과를 사용자 탱크가 자유자재로 지형 위를 움직이며 상대편 탱크와 전투를 하는 시스템이 개발된다.

• Journal of Industrial Technology
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• v.5
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• pp.81-89
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• 1985

A Mise-$\grave{a}$-la-masse method is to use a subsurface conductive mass itself as one current electrode of a pair by connecting it directly to one pole of a voltage source, the second current electrode being placed on the ground surface at a great distance and connected to the other pole. This paper is to study the modified Mise-$\grave{a}$-la-masse method using a water tank, that is, the second current electrode is placed on the underground level instead of being placed at a great distance, to find the geometry and the continuity of ore bodies.

• Journal of the Society of Naval Architects of Korea
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• v.51 no.3
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• pp.231-238
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• 2014

In this study, the self-propulsion tests are performed in INHA towing tank. And the effective wake characteristics of the KVLCC2 and the KCS models are compared by the experimental results. The form factor is independent of Reynolds number. To estimate the hydrodynamic performance of a full scale ship, the form factor is determined to consider attendant on Reynolds number. In this research, the power predictions are carried out considering the form factor difference of model and full scale ship. The results of this research could be used as one of the fundamental data to the powering performance prediction.