• 대한조선학회논문집
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• 제48권4호
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• pp.357-362
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• 2011

It has been often reported that a water-jet propelled high speed vessel lost the course keeping ability in seaway. In this study, model tests of a high speed vessel were performed to measure the running attitude and to check the course keeping ability. The model ship may lose the course keeping ability due to bad running attitudes such as bow drop. So model tests were carried out to improve the running attitude by changing the position of longitudinal center of gravity and using appendages at the bow and the stern of a model. The position of lateral center of pressure moved toward stern and the course keeping ability was improved by modifying the transom wedge angle.

• Journal of Advanced Research in Ocean Engineering
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• 제1권2호
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• pp.94-105
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• 2015

In this study, a thruster allocation method of a deep-sea working vessel was proposed with the aims of producing the demanded generalized forces and moment for dynamic positioning while at the same time minimizing total power. For this, an optimization problem for thrust allocation was mathematically formulated with design variables, objective function, and constraints. The genetic algorithms (GA) was used to solve the formulated problem. The proposed method was applied to an example of finding optimal thrust allocation of the deep-sea working vessel having 5 thrusters. The result showed that the method could be used to determine better strategy for thruster allocation of the vessel as compared to existing study.

• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.12-23
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• 2021

In the conventional experiment to assess the towing operations, the towing stability of the towed vessel has been evaluated under the condition without lateral motion of the tug-boat. However, the tug-boats may have a lateral force to change the direction of the towed vessel. In this study, experiments have been conducted considering unsteady conditions in the towing system. First, a towing test system in a Circular Water Channel (CWC) using the conventional experimental method is built. Second, the towing characteristics of the towed vessel are investigated using the conventional method, and they are compared with other research results and stability discriminant criteria. Third, the lateral motion of the tug-boat was modeled as a sinusoidal motion using a forced oscillation device changing frequency and amplitude. Finally, the discussion is given in terms of both towing- and course-stability of the towed vessel according to the lateral motion of the tug-boat.

• 한국해양환경ㆍ에너지학회지
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• 제14권2호
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• pp.73-80
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• 2011

어선용 고효율 표준 프로펠러 개발에 대해 고찰해 보았다. 어선용 프로펠러의 경우 모형시험이나 이론해석을 통한 정도 높은 설계가 이루어지지 않고 시리즈 데이터(주로 MAU 시리즈)에 의존하여 초기설계 수준에 머무르고 있는 실정이다. 본 연구에서는 52톤 어선을 기준으로 개발되었으며 기존 MAU 형 프로펠러보다 성능이 우수한 프로펠러를 손쉽게 설계, 적용할 수 있는 NACA형 단면을 사용한 시리즈 프로펠러 자료를 제공하기위한 연구를 수행하였다. 또 한 기존의 복잡한 설계 방식 대신에, NACA형 프로펠러를 표준화하여 보다 편리하게 사용할 수 있도록 하였다. 향후 모형 시험을 통한 추진 성능 및 캐비테이션 성능 검증을 수행할 계획이다.

• Journal of Advanced Research in Ocean Engineering
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• 제2권2호
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• pp.67-80
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• 2016

The resistance performance of an icebreaking cargo vessel with varied stem angles is investigated numerically and experimentally. Ship-ice interaction loads are numerically calculated based on the fluid structure interaction (FSI) method using the commercial FE package LS-DYNA. Test results obtained from model testing with synthetic ice at the Pusan National University towing tank and with refrigerated ice at the National Research Council's (NRC) ice tank are used to validate and benchmark the numerical simulations. The designed icebreaking cargo vessel with three stem angles ($20^{\circ}$, $25^{\circ}$, and $30^{\circ}$) is used as the target ship for three concentrations (90%, 80%, and 60%) of pack ice conditions. The comparisons between numerical and experimental results are shown and our main conclusions are given.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.485-488
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• 2012

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.557-559
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• 2012

• 대한조선학회논문집
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• 제47권4호
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• pp.589-597
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• 2010

The indoor noise of the naval vessel is very important considering hearing protection, improvement of working environment and easily communication between crews. When the environment of the naval vessel suffering from the noise is considered, it is very important to be quiet in the living area where the crews have a rest sufficiently. In addition, the noise of the working area should be reduced in order to increase working efficiency. Therefore, in this research, the satisfactions about the indoor noise are survey for crews working in a naval vessel. Through this survey, the relationship between the indoor noise and crew's satisfaction about it can be found. As a result, the limit of sound pressure level which almost all crew can be satisfied with the indoor noise about their living and working area is suggested base on the survey in this research.

• International Journal of Naval Architecture and Ocean Engineering
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• 제8권5호
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• pp.442-455
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• 2016

The resistance and seakeeping performance of a high-speed monohull vessel were investigated through a series of model tests in a towing tank. The hull had a slender wave-piercing bow, round bilge, and small deadrise angle on stern. Tests on the bare hull in calm water were first conducted and tests on spray rails followed. The spray rails were designed to control the flow direction and induce a hydrodynamic lift force on the hull bottom to reduce trim angle and increase rise of the hull. The maximum trim of the bare hull was $4.65^{\circ}$ at the designed speed, but the spray rails at optimum location reduced trim by $0.97^{\circ}$. The ship motion in head seas was examined after the calm water tests. Attaching the rails on the optimum location effectively reduced the pitch and heave motion responses. The vertical acceleration at the fore perpendicular reduced by 11.3%. The effective power in full scale was extrapolated from the model test results and it was revealed that the spray rails did not have any negative effects on the resistance performance of the hull, while they effectively stabilized the vessel in calm water and waves.

• 대한조선학회논문집
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• 제49권5호
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• pp.416-424
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• 2012

The MAU series has been usually used for the fishing vessel's propeller, which has been improved in consideration of the efficiency as well as the cavitation point of view in Pusan National University. The high efficiency standard series propeller(KF series) has been applied to the design of 52ton class fishing vessel's propeller in the previous study. The experimental study for the performance of the design propellers called KF series for 52 ton class fishing vessel has been conducted with five cases in Korea Ocean Research & Development Institute towing tank. The model tests have been carried out at different pitch ratio and expanded area ratio in comparison with the standard propeller to make the series chart. The KF series chart and the formula for performance expression have been completed on the basis of the experiment result.