• Journal of Ship and Ocean Technology
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• 제12권2호
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• pp.41-52
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• 2008

The development of a high-lift rudder is needed because low speed full ships such as the VLCC(Very Large Crude oil Carrier) have difficulty for obtaining enough lifting force from a common rudder. The rudder of a ship is generally positioned behind the hull and propeller. Therefore, rudder design should consider the interactions between hull, propeller, and rudder. In the present study, the FLUENT code and body fitted mesh systems generated by the GRIDGEN program are adopted for the numerical simulations of flow characteristics around a rudder that is interacting with hull and propeller. Sliding mesh model(SMM) is adopted to analyze the interaction between propeller rotation and wake flow behind hull. Several numerical simulations are performed to compare the interactions such as hull-rudder, propeller-rudder, and hull-propeller-rudder. Also, we consider relationships between the interactions. The results of present numerical simulations show the variation of flow characteristics by the interaction between hull, propeller, and rudder, and these results are compared with an existing experimental result. The present study demonstrates that numerical simulations can be used effectively in the design of high-lift rudder behind low speed full ship.

• 대한조선학회논문집
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• 제48권4호
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• pp.346-356
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• 2011

Rudder is to be located in extremely complicated flows generated and disturbed behind a hull and a propeller in operation. In order to estimate the rudder efficiency, it is quite important to investigate the disturbed flows due to the interaction under the hull-propeller and rudder condition. The purpose of the present research is to investigate the interaction between the hull-propeller and a high-lifting horn-type rudder through both numerical computations and experiments. A horn-type rudder implementing the Coanda effect of USB (Upper Surface Blowing) type is selected for its high efficiency of lifting force, and a 1/85 scaled model of 47K PC(Product Carrier) is manufactured for the purpose of the model test. The forces acting on the rudder during the experiment are measured using a three-component force gauge. Both cases are investigated in the hull-propeller-rudder condition and rudder open-water condition, which confirms that the flows generated under the former condition is considerably different from that of the latter condition.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2018년도 추계학술대회
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• pp.4-6
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• 2018

Traditional methods of research on ship maneuvering performance were estimated in calm water. Ship maneuverability in waves is of vital importance for navigation safety of a ship (ITTC, 2008). The accurate estimation of force and moment acting on the ship and rudder behind propeller are necessary because the rudder, propeller and hull interaction is of key importance. In addition, course-keeping ability and maneuvering performance of a ship can be significantly affected by the presence of wave. In this study, the model test is performed in the regular wave in the square wave tank in Changwon National University and the hydrodynamic force acting on the ship hull and rudder behind the propeller in various wave directions is investigated. The effect of wavelength and wave direction on hydrodynamic force acting on ship and rudder behind propeller in regular waves is discussed.

• 해양환경안전학회지
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• 제7권3호
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• pp.1-16
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• 2001

선박의 항행안전의 문제가 중요시됨에 따라 선박조종시뮬레이터를 이용한 운항훈련, 안전성 검토 등이 필요성이 중요하게 인식되고 있다. 또한 추진성능을 향상시킬 목적으로 다양한 선종이 출현되고 있고, 이에 따라 선박조종시뮬레이터의 개발에 있어서 선박의 데이터베이스는 필수적이라고 할 수 있다. 따라서 선종에 따른 수학모델을 각각 선박조종시뮬레이터에 적용시킴으로써 다양한 조종 시뮬레이션을 가능하게 할 수 있다. 본 논문에서는 우수한 추진성능을 목적으로 한 2축2타선박을 대상으로 조종운동 수학모델을 정식화하였다. 구체적으로 항만내에서의 저속시 조종운동을 구현할 수 있는 수학모델에 대해서 검토하였으며, 선체·프로펠러·타의 상호간섭에 대해서도 고려하였다. 또한, 수치시뮬레이션을 수행함으로써 2축2타선박의 기본적인 조종성능을 확인하였다.

• Journal of Ship and Ocean Technology
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• 제8권2호
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• pp.1-12
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• 2004

To keep the ocean environment from pollutions, strict international requirements on the controllability are arisen to the VLCC. Especially in low speed operations near the harbor, the VLCC is often supported by tug to replenish the insufficient rudder force. When water jet is blown to the flapped rudder, the Coanda effect induces a high-lift force by delaying stall and re-enforcing circulation in a large angle of attack (Lachmann 1961, Ahn 2003). Based on numerous research efforts, the rudder system supported by the Coanda effect was devised and its performances were evaluated in the towing tank for a large VLCC model. Hydrodynamic forces acting on the rudder system were measured with a water jet blowing on the rudder surface and compared with those acting on a conventional rudder. The effectiveness of the new rudder system was proven through an experimental evaluation.

• 대한조선학회논문집
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• 제59권1호
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• pp.1-8
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• 2022

To understand physical phenomena of ship maneuvering deeply, a numerical study based on computational fluid dynamics is required. A computational method that can simulate the interaction between the ship hull, propeller, and rudder will provide informative local flows during ship maneuvering tests. The analysis of local flows can be applied to improve a physical model of ship maneuvering that has been widely used in maneuvering simulations. In this study, the numerical program named as WAVIS that has been developed for ship resistance and propulsion problems is extended to simulate ship maneuvering by free-running tests. The six degree-of-freedom of ship motion is implemented based on Euler angles and the overset technique is applied to treat the moving grid of ship hull and rudder. The propulsion force due to a propeller is calculated by a panel method that is based on the lifting-surface theory. The newly extended code is applied to simulate turning and zig-zag tests of KCS and the comparison with the available experimental data has been made.

• 한국항해학회지
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• 제18권4호
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• pp.49-57
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• 1994

In marine transportation of bulk cargoes such as crude oil. ore, coal etc., a lot of full form ship which have poor manoeuvrability were presented in many countries. Since ship manoeuvrability depends upon many parameters namely hydrodynamic derivatives, interference factors etc., as external forces, it is of great importance that we investigate these values of parameters on analysis of manoeuvrability. In this paper, we investigated and analyzed interaction coefficients among hull-propeller-rudder for a full form ship by captive model test in circulating water channel, and then compared with experimental results by PMM test. A tanker model ship which has 0.83 as block coefficient and MMG mathematical models were used in this experiment. Almost same tendencies were found in qualitative analysis, even though more serial experiments were demanded in quantitative analysis.

• 대한조선학회논문집
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• 제37권1호
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• pp.40-49
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• 2000

본 논문에서는 흔타를 장착한 유조선의 조타기 토오크를 초기 설계 단계에서 추정할 수 있는 경험식을 통계분석 방법을 사용하여 개발하였다. 흔타의 타단독 상태에서의 유체역학적 특성은 Molland의 수정 양력선 이론에 따라 계산하였고, 선미 와류 내의 추진기와 선체의 영향은 실적선 자료의 회귀 분석을 통하여 추정하였다. 끝으로 본 방법에 의해 얻어진 조타기 토오크 추정경험식을 실적선에 적용한 후 그 결과를 비교하였으며, 매우 유의성이 높음을 확인하였다.

• 대한조선학회논문집
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• 제41권6호
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• pp.75-83
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• 2004

Ice rubble pieces broken by the bow impact load and side hull of an icebreaking vessel usually pass along the ship's bottom hull and may hit the propeller/rudder or other stern structures causing serious damage to ship's hull . Therefore it is important to estimate the size of broken ice pieces during the icebreaking process. The dynamic interaction process of icebreaker with infinite ice sheet is simplified as a wedge type beam of finite length supported by elastic foundation. The wedge type ice beam is leaded with vertical impact forces due to the inclined bow stem of icebreaking vessels. The numerical model provides locations of maximum dynamic bending moment where extreme tensile stress arises and also possible fracture occurs. The model can predict a failure length of broken ice sheet given design parameters. The results are compared to Nevel(1961)'s analytical solution for static load and observed pattern of ice sheet failure onboard an icebreaker. Also by comparing computed failure length with the characteristic length, the meaning of ice rubble sizes is discussed.

• 대한조선학회논문집
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• 제35권4호
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• pp.19-26
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• 1998

본 논문은 선박의 조종성능을 추정하기 위하여 선체에 작용되는 유체력과 선체-프로펠라-타 상호 간섭 계수들에 대해 실험 및 반경험적 방법을 사용한 유사선 개념[1,2]을 도입하였다. 유사선 개념은 새로운 선박과 가장 유사한 선박의 기 실험된 데이타를 기본으로 채택한다. 유사선 개념을 적용하기 위해 기 실험된 선박에 대한 실험데이타가 존재해야 되며, 선체력의 변화를 평가하기 위한 반경험적방법이 채택되어야 하고, 기 실험된 선박의 데이타를 수정할 방법이 반드시 존재해야 된다. 유사선 개념을 근간으로, 만재흘수 상태의 실험결과를 이용하여 경하 및 하기만재흘수 상태에서의 선박조종성능을 추정하였고, 또한 유사선으로 기 실험된 선박을 선택하여 새로운 선박의 조종성능을 추정하였다. 본 논문의 계산 방법이 초기 설계단계에서 선박의 조종성능을 정확하게 추정할 수 있음을 확인하였다.