• 한국전산유체공학회:학술대회논문집
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• 2005.04a
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• pp.30-34
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• 2005

고속 선박을 추진하는 한 방법으로 널리 사용되는 물분사 추진은 물을 내부 덕트로 빨아들여 임펠러로 물을 가속시켜 노즐을 통해 분사시킴으로써 입출구의 운동량차이에 의해 추력을 얻는 추진장치이다. 선박의 목적에 따라 사용되는 다양한 형태의 물분사 추진기의 개발을 위하여 모형실험을 통하여 그 성능을 검증하는 부분에서 로터의 피치각 변화에 따른 추진기의 성능 실험을 하는 것은 많은 비용과 시간이 따른다. 따라서 이러한 문제를 해결하기 위하여 본 연구에서는 추진기 내부의 유동장을 4가지 피치각에 따라 추진력을 3차원 비압축성 Navier-Stokes 방정식을 이용하여 해석하였다. 로터의 회전을 고려하여 슬라이딩 다중 격자기법을 적용하였고 추력계수, 토크계수, 그리고 모멘텀을 해석 결과와 비교 분석을 통하여 추진기의 성능과 효율을 추정하였다.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.2 s.146
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• pp.164-170
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• 2006

To improve ship's maneuverability and carry out special goal POD propulsion system was equipped as propulsion and maneuvering system. To predict the maneuverability of a ship with POD propulsion system HPMM tests and POD open water test are carried out. In this paper modular model with 4 degree of freedom of a ship with twin POD propulsion system is presented. To use modular model the forces of POD propulsion system are measured separately from the hull forces. The measured forces and moments are analyzed by using modular model and whole ship model The simulation results of modular model are compared with those of whole ship model. From the present study it is Possible to analyze HPMM tests of a ship with twin POD propulsion system by modular model.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.4
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• pp.327-332
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• 2012

International Towing Tank Conference (ITTC) recommended verifying a ship's ability to move transversely at zero forward speed without altering heading by a crabbing test. In sea trial, all available propellers/rudders/thrusters should be used to find the maximum possible transverse speed. For estimating crabbing ability in the design stage, tests to estimate possible swaying force and yawing moment range using all available propellers/rudders/thrusters are conducted. By butterfly diagram, which compares possible swaying force and yawing moment range with external swaying force and yawing moment by wind, a ship's crabbing ability can be estimated. In this study, model tests of a cruise vessel equipped with bow thrusters and POD system were conducted to find out her crabbing ability in the design stage. To mimic quay condition, a model quay-wall was set in the towing tank.

• Journal of the Society of Naval Architects of Korea
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• v.50 no.6
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• pp.429-435
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• 2013

Recently, to improve the safety and maneuverability at fairway around harbor the POD system has been equipped on a ship. And the interest about maneuvering characteristics of a cruise ship has been increasing. In this paper the mathematical model of maneuvering motion of a cruise ship with twin POD system in general speed and slow speed are presented. And the maneuvering coefficients of mathematical model are obtained from the captive model tests using CPMC(Computerized Planar Motion Carriage). Computer simulation using mathematical model in general speed and slow speed are carried out and compared with the results of free running model test with the same model ship. The differences between the mathematical models are compared and discussed. In this paper the mathematical models, the results of captive model test and simulation results are presented.

• Journal of the Society of Naval Architects of Korea
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• v.61 no.3
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• pp.161-169
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• 2024

In order to investigate cavitation performance for the azimuth thruster in Large Cavitation Tunnel (LCT), the cavitation test apparatus was designed and manufactured. Generally the model scale is determined by the pod dynamometer with about 70mm diameter. Recently as ships with azimuth thruster have become bigger, the problem of the model ship installation was occurred. The model ship with pod dynamometer couldn't be installed in the LCT test section. The cavitation test apparatus and technique which can conduct the cavitation test without pod dynamometer were developed. The cavitation tests were conducted in torque identity method instead of thrust identity method. The target ship with azimuth thruster is 18K LNG bunkering vessel. As the full-scale ship test was conducted, the model cavitation tests were conducted at the same operating conditions. The fluctuating pressure levels of the full-scale ship were compared to those of the model tests. Another model cavitation test was conducted in the foreign institute and the cavitation observation results were compared to those of LCT. Through the comparison with the existing results, it is thought that the cavitation test for the azimuth thruster can be conducted in torque identity method.

• 한국전산유체공학회:학술대회논문집
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• 2001.05a
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• pp.209-214
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• 2001

RANS 방정식의 수치해법을 사용해서 tractor와 pusher 방식의 포드 프로펠러 주위 점성유동을 계산함으로써 포드형 전동 추진기의 추진 특성을 파악하고자 하였다. 본 연구에 사용한 수치해석 방법을 검증하기 위하여 최근 국내에서 모형 실험이 수행된 포드 프로펠러 형상에 대해 수치계산을 수행하고, 계산으로부터 얻어진 tractor와 pusher 방식의 포드 프로펠러에 대한 단독 성능을 실험 결과와 비교하였다. 또한, 포드에 작용하는 압력 및 프로펠러 날개 주위의 유동을 분석함으로써, 포드가 프로펠러의 추진 성능에 미치는 영향과 tractor와 pusher 추진 방식의 특성을 살펴보았다.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.3
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• pp.469-475
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• 2010

The operation scenarios, types of ice, draft and propulsion system are important design point on the beginning stage of the ice breaking vessel. The concept of hull form in ice breaking vessel has to compromise the performance according to the operation route especially if ship is operating in ice and ice free water. The several hull forms were proposed to optimize the capability of the vessel in this paper. The effect of hull form according to type of ice is also discussing and explaining the ice resistance in each ice type as like pack ice, brash ice, level ice, rubble ice and ice ridge. The draft effect was examined and propulsion system for example FPP(Fixed pitch propeller), CPP(Controllable pitch propeller) and POD system was compared focusing on the propulsion efficiency.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.98-99
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• 2016

The aim of study is to develop a dual driven ship berthing/deberthing system with $360^{\circ}$ steerability. A large ship used bow thruster, side thruster and pod propulsor etc. when approaching to a pier. But as marine leisure boats become large-scaled, the number of accidents is recently increasing what caused a ship to crash into a ship and a ship to crash into mooring facilities during berthing/deberthing on a marina. To solve the problem, the control responsiveness of a joystick connected with two motors and a propeller was checked and torque was increased by the electromagnetic design of magnetic gear. A sea trial test was carried out to investigate a performance of the developed system in the real sea.