• 대한조선학회논문집
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• 제44권6호
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• pp.551-563
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• 2007

Numerical analysis for flow characteristics of a twin skeg container ship was carried out according to skeg vertical angles($0^{\circ}$, $10^{\circ}$, $20^{\circ}$) and skeg distances(16m, 20m, 24m) by using a commercial CFD code, FLUENT. Computed: pressure distributions, wake distributions and resistance coefficients have been compared with experimental and WAVIS results carried out by MOERI. Flow characteristics from numerical analysis such as nominal wake fractions, wake distribution and directions of the transverse vectors give good agreement with WAVIS results, even though there are quantitative discrepancy comparing with experimental measurements at the propeller plane. It is found that the better resistance performance can be obtained with the increase of the skeg vertical angle and the decrease of the skeg distance, which are mainly caused by viscous pressure resistance due to the skeg form and pressure recovery around the skeg. In addition, a vertical angle of the skeg gives more effect to the resistance coefficient comparing with the skeg distance. On the basis of results of the present study, it shows that numerical analysis using the commercial code, FLUENT, is useful and efficient tool for the evaluation of the complex stern hull form with twin-skegs.

• 기술사
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• 제34권3호
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• pp.46-51
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• 2001

Patent Technology Map analysis of future ship type. Example ship type : Hydrofoil Craft. Air Cushion Vehicle Surface Effect Ship, Twin Hull Ship, Wing In Ground Effect Ship, Elelctrial Propulsion Ship, Icebreaking Ship, Submarine, LNG Ship Conclusion of future shipbuilding Technology Policy

• 해양환경안전학회지
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• 제1권1호
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• pp.95-106
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• 1995

The small-waterplane-area-twin-hull(SWATH) ship has been recognized as a promising high performance ship because of her superior seakeeping characteristics and large deck area for various operations compared to the conventional monohull ship. significant advances in analytical technics for the prediction of the ship motions, wave loads and structural responses, structural fatigue and its prediction, and hull vibration for ship motions, wave loads and structural responses, structural fatigue and its prediction, and hull vibration for SWATH ship have been much developed during the last twenty years. Based on these developments in technology an integrated computational procedures for prediction wave loads and structural responses can be used to get a accurate results. But the major problem of SWATH ship's structural design is the accurate prediction of structural responses by the maximum critical loads likely to be experienced during the life of SWATH. To get a easier and safer computational procedures and the analytical approach for determining the accurate structural responses, a case study has been presented through the project experienced.

• 대한조선학회지
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• 제23권4호
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• pp.35-43
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• 1986

Recently, the SWATH concept hull form which is capable of high speed navigation with small oscillatory motions in waves, was developed from the catamaran type hull forms. This paper discribes a method to predict motion responses of a SWATH ship in regular waves using the strip theory. The 2-dimensional hydrodynamic problem was solved using the improved Green integral equation which is free from the irregular frequencies. The effects of viscous drag which is dominant in heave damping of the SWATH ship are taken into account. Further, the effects of the stationary stabilizing fins which is important in high speed performance of the SWATH ship are included in the equation of motions. It seems that the motion responses calculated by the present method show better agreement with experimental results than other existing numerical results.

• International Journal of Naval Architecture and Ocean Engineering
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• 제7권3호
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• pp.466-477
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• 2015

In this study, a numerical prediction method on manoeuvrability of Wind Turbine Installation Vessel (WTIV) is presented. Planar Motion Mechanism (PMM) captive test for the bare hull of WTIV is carried out in the model basin and compared with the numerical results using RANS simulation based on Open-source Field Operation And Manipulation (OpenFOAM) calculation to validate the developed method. The manoeuvrability of WTIV with skeg and/or without skeg is investigated using the numerical approach along with the captive model test. In the numerical calculations, the dynamic stability index which indicates the course keeping ability is evaluated and compared for three different hull configurations i.e. bare hull and other two hulls with center skeg and twin skeg. This paper proves that the numerical approach using RANS simulation can be readily applied to estimate the manoeuvrability of WTIV at the initial design stage.

• 대한조선학회지
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• 제19권4호
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• pp.39-45
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• 1982

A floating rig, which has been used to develop the ocean resources has a common characteristics with the catamaran ship that it is composed of the two simple hulls. So the motion responses of the floating rig can be predicted theoretically with the aid of the strip method as those of the catamaran. And for the strip method, the two-dimensional hydrodynamic coefficients are the most important inputs to predict the results accurately. In this report, a theoretical method is proposed for calculating two-dimensional hydrodynamic forces and moments acting upon arbitrary shaped twin-hull cylinders, which are forced to make a heaving, swaying and rolling oscillation about their mean position on the free surface of a finite depth water. The theoretical results by making use of the singularity distribution method are presented. The accuracy of the coefficients was confirmed to be reasonable by the comparison with the Ohkusu's results for two circular cylinders in an infinite depth water. The depth effects on two-dimensional hydrodynamic coefficients for two circular cylinders are also checked. In some range of wave numbers, large differences in the behavior of hydrodynamic coefficients between for a finite depth and for an infinite depth are shown.

• 대한조선학회논문집
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• 제31권4호
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• pp.109-118
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• 1994

본 연구에서는 쌍동형 표면효과선 선체 구조의 최소 중량 설계를 수행하는 방법을 제시하고, 이에 따르는 전산 프로그램을 개발하고자 한다. 본 방법은 DnV의 설계 하중 및 강도 기준을 이용하며, 격자 구조 해석을 통해 종거어더와 횡늑골의 상호 영향을 반영하여 설계에 활용하고, 쌍동 선체 사이의 연결 구조에 대해 비틂 강도 해석을 수행하여 횡격벽 설계를 수행한다. 또한 부분구조의 최적화를 통해 중앙 단면 전체의 최적화에 도달하는 방법을 적용함으로써 최적화의 효율을 증가시키고 있다. 본 방법을 적용한 결과, 초기 설계 결과에 비해 20% 정도의 선체 중량 감소효과를 확인할 수 있고, 최적의 횡늑골 간격도 계산될 수 있다.

• 동력기계공학회지
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• 제11권1호
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• pp.98-106
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• 2007

This paper presents a statistical prediction procedure for the propeller racing of ships with twin screw propellers sailing in ocean waves. The propeller racing is one of the most important factors of seakeeping qualities in relation to the safety of main engine and shafting system. It is especially significant key word for designing the twin-screw-propeller-type ship in view of allowable maximum propeller diameter etc.. In former studies, the propeller racing generally means the situation (propeller exposed) in which the relative motion amplitude between ship hull and wave surface would exceed a depth of point in rotary disk propeller. Therefore, it seems that the magnitude of the amplitude and its exceeding frequency have been examined as a principal subject of study as usual. However, the time during which the amplitude exceeds a depth of point must be also one of most important factor affecting the trend of propeller racing. This paper proposes a simply practical method for estimating the time lasting of exposed propeller related to twin screw propeller racing in rough confused seas on the basis of the statistics. Then, it is confirmed that the practical method is useful and convenience for considering the propeller racing in the stage of the basic design.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2017년도 공동학술발표회
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• pp.129-130
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• 2017

본 연구에서는 쌍동형 카페리에 대한 기본 구조 설계 및 구조 해석을 위한 기법을 제시한다. 카페리와 같이 길이 50미터 이상 길이와 폭/비가 12보다 큰 중/소형 고속 선박의 강도 해석에 대한 규정이나 방법론은 아직까지 명확하게 제시되지 않고 있다. 따라서 본 논문에서 부재의 스캔틀링은 한국선급기준을 적용하였고, 설계안에 대한 구조강도 검증을 위해서 카페리 전용선박 기준에 의해 추가적으로 검증하였다. 특히, 카페리 전용선박 기준을 적용하여, Hull girder ultimate strength를 추가적으로 수행하여, 현재 기준에 의한 설계의 모호성을 극복하도록 제안하였다. 본 연구를 통해 도출된 연구 결과는 앞으로 고속 쌍동형 카페리의 구조설계 및 구조해석에 관련된 기본적인 자료로 유용하게 활용될 것으로 예상된다.

• 대한조선학회논문집
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• 제33권4호
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• pp.60-65
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• 1996

1축 1타선에 대한 조종운동 수학모델은 통상적인 경우 이미 확립되어 널리 사용되고 있다. 또한 저속이나 천수역에서의 조종운동계산에도 응용되고, 새로운 국면의 조종운동 해석에도 기존의 조종수학 모델이 근간이 되고 있다. 한편 2축 2타선과 같은 특수선형에 대해서는 Lee 등에 의한 상세한 구속모형시험 결과로 그 특성이 알려지게 되었고, 1축 1타를 기본으로 하는 기존 수학모델에 약간의 수정을 가함으로서 충분이 조종운동을 추정할 수 있음을 보였다. 본 논문에서는 2축 2타선에 대한 Propeller Effective Wake($1-w_p$)와 유효중립타각 (Effective Neutral Rudder Angle) ${\delta}_R$에 대한 추정모델을 제안하고, Hull의 유체력에 관해서도 Inoue의 추정식을 사용하여, 초기설계단계에서 선박의 주요치수, Propeller 및 타 제원만으로서 개략적인 2축 2타선의 조종운동 계산을 가능하도록 하였다. 이 추정법에 의한 조종운동 계산결과를 엄밀한 구속모형 시험 Data에 의한 계산과 비교하여, 본 논문에서 제안된 추정법의 유용성을 검증하였다.