• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 추계학술대회 논문집
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• pp.89-93
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• 2002

Resistance performance of 6.67 G/T class fishing vessel is experimentally investigated in low and middle speed ranges to find out the effect of a new chine. The tests are performed for four different cases in the circulating water channel(CWC). Wave patterns are observed together to make clear the relation between the resistance performance and the wave characteristics. The results show that the new chine can be one of the effective device to reduce the resistance.

• 대한조선학회논문집
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• 제46권3호
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• pp.268-278
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• 2009

The present study focused on evaluation for the performance of the Flow Control Flat Plate (FCFP) attached in the stern side of the ship. The important function of this FCFP is to enhance the resistance performance through the decrease of stern sinkage and the propulsive performance by the adjustment of inflow velocities in the propeller plane. Two different hull forms were considered to identify the effects of the FCFP. The attachment position, the angle and the size of the FCFP were studied in this numerical simulation. In this paper, the roles of the FCFP were intended to analyze fully through the numerical interpretation.

• 해양환경안전학회지
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• 제24권4호
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• pp.467-474
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• 2018

본 연구의 목적은 2가지 선속에서 운항하는 선박의 선형 설계 자동화에 관한 것이다. 가장 기본적인 선박의 형상을 가지는 60계열($C_B=0.6$) 선박을 대상선박으로 선택하여 연구를 수행하였다. 선박 형상의 향상 방향은 저항성능 향상의 관점이며, 특히 선박의 형상과 밀접한 관계를 가지는 조파저항성능을 향상하기 위한 선박 형상 설계 자동화를 수행하였다. 본 연구의 목적을 실현하기 위하여 최적화 기법과 저항 성능을 예측하는 기법 그리고 선형의 형상을 변경하는 기법을 접목하여 선박 형상 설계 자동화 소프트웨어를 개발하였으며, 개발된 소프트웨어를 대상선박에 적용하였다. 최적화 기법으로는 순차이차계획법(sequential quadratic programming method)를 사용하였으며, 조파저항성능을 예측하기 위하여 포텐셜기저 패널법(potential-based panel method)을 사용하였다. 선박 형상의 변경은 가우시안형 수정함수법(Gaussian-type modification function method)를 개발하여 적용하였다. 개발된 소프트웨어를 사용하여 대상선박의 서로 다른 두 가지 선속에 대하여 설계를 수행하고 그 결과를 서로 비교하였다. 그리고 개발된 프로그램의 타당성을 검증하기 위하여 모형시험을 수행하여 구한 실험값과 수치해석을 수행하여 구한 계산값을 서로 비교하였다.

• 한국해양공학회지
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• 제29권2호
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• pp.111-119
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• 2015

In the initial ship design stage, performance predictions are generally carried out before and after the hull form design. The former is based on the main dimensions and power information, and the latter is based on the geometry of the hull form and propeller. This paper deals with the practical application of neural networks for the prediction of a ship's performance factors before and after the hull form design. For this, the hull form parameters that affect the performance are studied, and an optimal neural network structure based on the SSMB database is constructed. By comparing the results predicted by neural networks and the model test results, we confirmed that neural networks can be applied to practically evaluate the performance in the initial ship design stage.

• 대한조선학회논문집
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• 제41권6호
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• pp.33-39
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• 2004

The performance of a deep water drillship, is investigated with the view of the characteristics of the thrusters and the resistance increasement due to moonpooi. The model tests have been performed to obtain the resistance of two drillships with the moonpooi open and closed including shape changes of moonpool step. To design the DP system, thrust forces of azimuth thrusters have been measured during azimuthing at zero speed condition. Thrusters, azimuthing under the bottom of ship, have the interactions of the other thrusters due to flow changes made by other thrusters, and the existence of ship hull makes the thrust deduction higher than when the thrust operates by itself. The resistance increasement due to the moonpooi is highly dependent on the step height of the moonpool and the draft. It is found that the height of moonpool step can reduce the resistance increasement by moonpool.

• 한국항해항만학회지
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• 제36권10호
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• pp.787-793
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• 2012

최적화기법과 선형변환 자동화기법을 도입하여 고속 중형 Ro-Pax선박의 조파저항성능을 향상시킬 수 있는 선형설계방법에 대하여 연구하였다. 최적화기법으로는 SQP(sequential quadratic programming)을 적용하였으며, 선형변환 자동화기법으로는 NURBS(Non-Uniform Rational B-Spline)기법을 적용하였다. 목적함수인 선박의 조파저항성능을 예측하기 위하여 비선형 자유수면 경계조건과 선체의 침하량을 고려한 비점성 유동 해석 기법인 패널법을 적용하였다. 기준선형에 대하여 선형최적화를 수행하였으며 그 결과로 도출된 최적선형에 대하여 모형선을 제작하여 모형시험을 수행하였다. 기준선형과 최적선형에 대한 수치해석을 수행하여 얻은 결과와 최적선형에 대한 모형시험을 수행하여 얻은 결과를 서로 비교하였다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1998년도 춘계학술발표회 논문집
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• pp.90-100
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• 1998

There is a limitation for a ship which is sailing on sea to gather weather and seastate informations. To make up for this weakness , land organizations can gather wider variety of information and evaluate the seakeeping performance on ship. and supply this information to the ship. In this study, calculated the response amplitude of ship motions with the weather information provided in real time, the norminal speed loss with obtaining increased of resistance caused by wave and stochastic process of the seakeeping performance elements. And the results have been achieved to develop a system whichcan evaluate the synthetic seakeeping performance. Using this system , the results have been studied to determine the feasibility of using this simulation inactual operation onboard ship.

• 대한조선학회논문집
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• 제31권1호
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• pp.50-62
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• 1994

본 논문에서는 비대선형에서 구상선수의 형상변화가 저항성능에 미치는 영향을 조사해 보기 위하여 구상선수 계열들을 창안하고 이들의 모형시험 결과를 비교 분석한 내용이 기술되었다. 구상선수의 형상을 결정짓는 7가지의 변수를 생각하고 이들을 체계적으로 변화시켜 구상선수 형상변화의 영향을 실험적으로 조사하도록 계획하였다. 총 23개 선형의 모형선을 제작하였으며, 각 선형에 대하여 저항시험, 유선조사시험 및 선측파고 계측시험이 수행되었다. 구상선수의 형상변화와 모형시험 결과와를 상호 비교 분석하기 위하여 유사한 특성의 구상선수들을 모아서 9개 그룹으로 분류하였으며 각 그룹 별 저항성분의 변화 경향을 분석해 본 결과 비대선에서는 형상저항이 전저항에 지배적인 영향이 있음을 확인하였다. 또한 모형시험 결과 및 이의 통계적 분석 자료로부터 비대선에서는 구상선수 주위의 유선의 방향이 저항성분들과 밀접한 관계가 있으며 저항성분들 중에서도 형상저항과 더욱 밀접한 관계가 있다는 사실을 발견하였다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.11-19
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• 2020

In recent years, oil prices have continued to be low owing to the development of unconventional resources such as shale gas, coalbed methane gas, and tight gas. However, shipping companies are still experiencing difficulties because of recession in the shipping market. Hence, they devote considerable effort toward reducing operating costs. One of the important parameters for reducing operating costs is the frictional resistance of vessels. Generally, a vessel is covered with paint for smoothing its surface. However, frictional resistance increases with time owing to surface roughness, such as that caused by fouling. To prevent this, shipping companies periodically clean or repaint the surfaces of vessels using analyzed operating data. In addition, studies using various methods have been continuously carried out to identify this phenomenon such as fouling for managing ships more efficiently. In this study, numerical simulation was used to analyze the change in the resistance performance of a ship owing to an increase in surface roughness using commercial software, i.e., Star-CCM+, which solves the continuity and Navier eStokes equations for incompressible and viscous flow. The conditions for numerical simulation were verified through comparison with experiments, and these conditions were applied to three ships to evaluate resistance performance according to surface roughness.

• 수산해양기술연구
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• 제59권4호
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• pp.344-353
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• 2023

In the actual sea, the additional resistance due to external force such as wind, current and wave is accompanied, and the required power is added in response to these resistance. Especially when the ship is sailing at low speed, the effects of wind and current have a great impact on the safe control of the ship. Likewise, it is thought that the effects of wind and current have a great impact on the trawl ship control since the towing speed of a bottom trawl ship is a low speed of 3 to 4 knots. If the reduce of ship speed and the increase of engine power due to the influence of wind and current can be identified, the safe towing power can be calculated based on a given engine output. Thus, the appropriate size of a fishing gear can be determined. In this study, a total of 20 trawl operations were conducted for seasonal maritime research in the same research area according to the operation mode of propeller. Based on navigation data, trawl fishing data, and engine performance data acquired during the towing fishing gear, and data of ship speed, hull resistance, fishing gear resistance, wind force and current force according to an incidence angle were estimated. The overall power for these loads was calculated and compared with the measured engine power, and the effects of wind force and current force on the engine power were investigated.