• Journal of the Society of Naval Architects of Korea
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• v.34 no.2
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• pp.27-38
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• 1997

This paper is concerned with the calculation of the wave resistance for SWATH ships based on a low order Rankine source panel method. Two types of free surface boundary conditions, Dawson type (double model approximation) and Kelvin type (free stream approximation) are used. For the free surface boundary calculation, an analytic differentiation is employed instead of implementing a finite difference scheme. Then, the radiation condition is satisfied by, so called, the panel shift method. The numerical results using the above two methods are compared with those using the thin ship/modified slender body approximation and also with the experimental results. The SWATH models considered are a single strut SWATH and a twin strut SWATH together with the variations of two demihull separation distance. In order to prove the validity of the program developed, the numerical calculations for a Wigley mono hull and Wigley twin hulls are compared with the available experimental results.

• Journal of the Society of Naval Architects of Korea
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• v.29 no.4
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• pp.66-74
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• 1992

A panel method in the spirit of Hess & Smith(1962), and also of Dawson(1977) was developed to compute the wave resistance of a submerged, or a surface piercing, body moving in the water of finite depth. As a boundary condition on the free surface what is called the Poisson equation is used, while Yasukawa(1989) chose the Dawson equation for which the double-body flow is regarded as the basic one. In order to satisfy the boundary condition on the bottom surface automatically, the sum of a Rankine source and its image with respect to the bottom surface is chosen as the Green function, and hence the singularity is distributed only on the body and on the free surface thereby decreasing the required number of panels dramatically, compared to that of Yasukawa, without the consequential loss of accuracy. Calculations were done for a submerged sphere and for the Wigley hull, and the results are compared with other existing analytical and numerical data.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.138-140
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• 2007

폰툰형 레저보트는 쌍동식 또는 삼동선식의 안전성이 확보된 선체와, 다양한 기능을 만족할 수 있는 상부구조로 구성, 건조비 뿐만 아니라 레저 접근성이 용이한 보트로서, 해양레저 선진국에서는 내수면뿐만 아니라 해수면에서도 함께 즐길 수 있는 가족형 레저보트로 인식되어 최근 보급이 확대되고 있는 추세이다. 그러나 폰툰형 레저보트는 최적의 공간활용을 위해 사각모양의 갑판형태로 인해 유체의 저항에 취약한 단점이 있다. 이로 인해 선저형상, 추진시스템 및 조향운전장치 뿐만아니라 선수선저부의 슬래밍 충격에 대비한 구조강도 등 체계적인 연구를 통한 개발이 필요하다. 이에 본 연구에서는 2가구 4인 가족단위로 함께 즐길 수 있는 안전성이 높고, 낚시, 스쿠버 둥을 위한 편의시설이 확보한 선형 최적형상 연구 및 구조강조 해석을 통한 9인승 규모의 폰툰형 레저보트를 개발하고자 한다.

• Journal of computational fluids engineering
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• v.21 no.4
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• pp.78-84
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• 2016

In this paper, turbulence models for considering roughness in the open source code(OpenFOAM) was investigated. Wall function in the RANS(Reynolds-averaged Navier - Stokes) turbulence model was modified considering roughness on the flat plate by using roughness function. Correlation between the first layer height in the CFD model and roughness height of the plate was observed, and the most proper roughness function, and the first layer height from the plate wall in the CFD analysis was suggested in this paper.

• Journal of Ocean Engineering and Technology
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• v.27 no.1
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• pp.31-36
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• 2013

In this paper, the effects of a foil attached to a ship on the ship motion, added resistance, and thrust generation in waves are analyzed. The unsteady theory for a two-dimensional foil is introduced to determine the coupled motion responses of the ship and foil. The thrust caused by the oscillating foil is evaluated and compared to the added resistance of the ship, so that a positive net thrust can be possible in waves. A comparison of the results of unsteady, quasi-steady, and experimental analyses is performed.

• Journal of Ocean Engineering and Technology
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• v.16 no.6
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• pp.71-75
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• 2002

In this paper, a study on the principal performance of the purse seiner ship in two vessel formations was conducted. For this task, the outline of the purse seiner fishing system in two vessel formations was reviewed. At the same time, based on the general arrangement plan, hull from of the main vessel was developed. And the stability and ship motion characteristics of the ship design were estimated. Finally, to verify the characteristics of the resistance and self-propulsion coefficient, a model test in a circulating water channel was performed. As n result, it is anticipated that this presentation will be used as the foundation material for research of purse seiner.

• Journal of computational fluids engineering
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• v.20 no.1
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• pp.57-64
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• 2015

This paper describes a volume of fluid(VOF) method, mRHRIC for the simulation of free surface flows around ship hulls and provides its validation against benchmark test cases. The VOF method is developed on the basis of RHRIC method developed by Park et al. that uses high resolution differencing schemes to algebraically preserve both the sharpness of interface and the boundedness of volume fraction. A finite volume method is used to solve the governing equations, while the realizable ${\kappa}-{\varepsilon}$ model is used for turbulence closure. The present numerical results of the resistance performance tests for DTMB5415 and KCS hull forms show a good agreement with available experimental data and those of other free surface methods.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.187-193
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• 2011

In this report, We compared the actual test with the result of pow calculation and Resistance/Self-propulsion of the ship using STAR-CCM+ which is the commercial Reynolds Averaged Navier-Strokes(RANs) Solver. The calculation model was the KRISO Container Ship and 205K Bulk Carrier of Sungdong shipbuilding company. For this calculation, We used Realizable K-Epsilon model for flaw analysis, VOF method for the free surface creation, Moving Reference Frame method for reducing the POW calculation time, and Sliding Mesh method for Self-Propulsion analysis. Calculation of Resistance and Self-Propulsion includes the free-surface. And all calculations in this report were based on unstructured grids.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.83-83
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• 2014

선박건조에 사용되는 도료 중 SPC(self-polishing copolymer) A/F(anti-fouling) 도료의 주된 기능은 해양생물의 부착 등 해양생물에 의한 오염을 방지하는 방오성능으로 인식되어 왔으나, 최근 방오성능 뿐 아니라 선박의 운항 시 선체저항을 줄임으로써 발생되는 연료절감효과와 선박의 미관을 위한 변색지연 등 SPC A/F 도료의 다른 기능에 많은 관심을 가지게 되었다. 이러한 관심과 사용자의 요구에 따라 도료사에서는 항력의 감소를 가져 올 수 있는 Silyl acrylate copolymer로 디자인 된 Silyl acrylate SPC A/F 도료를 개발하였으나 SPC A/F 도료의 방오제(biocides) 종류에 따른 방오성능 차이를 비교 평가 할 수 있는 객관적 자료가 부족하여, 본 연구를 통해 SPC A/F 도료의 종류 별 방오성능을 평가하고자 한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.216-217
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• 2018

소형 활주선의 경우, 대형 저속선 대비 항주자세의 변화가 크기 때문에 CFD 해석시 저항성능과 운동성능 결과에 오차가 발생할 수 있다. 본 연구에서는 Warped 2 선형을 대상으로 상용 CFD 코드인 STAR-CCM+ v9.04를 사용한 CFD해석을 수행하여, 이를 모형시험 결과와 비교하여 오차를 확인하였고, 또한 오차의 원인을 분석했을 때, 선체 하부의 Numerical ventilation 현상과 Spray 영역에 문제가 있다고 판단하였다. 추후 연구에서는 오차 해결 방법으로 VOF Phase replacement 기법과 Spray 영역에 대한 격자 최적화 방법을 연구하고자 한다.