• 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.

• International Journal of Naval Architecture and Ocean Engineering
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• 제9권6호
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• pp.677-692
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• 2017

A numerical approach based on a potential flow method is developed to simulate the unsteady interaction between propeller and rudder. In this approach, a panel method is used to solve the flow around the rudder and a vortex lattice method is used to solve the flow around the propeller, respectively. An iterative procedure is adopted to solve the interaction between propeller and rudder. The effects of one component on the other are evaluated by using induced velocities due to the other component at every time step. A fully unsteady wake alignment algorithm is implemented into the vortex lattice method to simulate the unsteady propeller flow. The Rosenhead-Moore core model is employed during the wake alignment procedure to avoid the singularities and instability. The Lamb-Oseen vortex model is adopted in the present method to decay the vortex strength around the rudder and to eliminate unrealistically high induced velocity. The present methods are applied to predict the performance of a cavitating horn-type rudder in the presence of a 6-bladed propeller. The predicted cavity patterns compare well with those observed from the experiments.

• 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.

• 대한조선학회논문집
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• 제50권6호
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• pp.421-428
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• 2013

This study aims at numerically investigating the angle of attack characteristics of the rudder behind a rotating propeller. The rotating propeller of 5 blades and the full spade rudder are placed in the numerical water tunnel with a uniform flow condition to consider propeller-rudder interaction. The turbulence closure model is employed to simulate the three-dimensional unsteady incompressible viscous turbulent flow around the propeller and the rudder. The present numerical method are well verified by comparing with the experimental results. In order to identify the dependence of the angle of attack of the rudder on the rudder angle, a wide range of rudder angles is considered. The present study carried out the quantitative and qualitative analysis of the angle of attack in terms of the pressure distribution, streamlines and the evaluation of the flow incidence, resulting in that the angle of attack increases as we move from the root and the tip to the center of the rudder, regardless of the rudder angle. The distribution of the angle-of-attack along the span is strongly affected by rotating propeller flow and rudder angle. Consequently, the distribution of the angle-of-attack of the oncoming flow against the rudder leading edge plays a role in determination of rudder performance.

• International Journal of Ocean System Engineering
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• 제3권4호
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• pp.169-174
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• 2013

The computational fluid dynamics software FLUENT is used to calculate and compare the hydrodynamic performance of the propeller-rudder system of a 42-m trawler, which is installed with a ducted propeller. The effects of rudder on the hydrodynamic performance of the ducted propeller and the wake flow behind the propeller are firstly investigated. In addition, the different rudder angles are also considered to further study the performance of this system.

• 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.

• 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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• 제38권4호
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• pp.11-22
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• 2001

프로펠러-WIG(Wing in Ground Effect)선의 상호작용 및 성능을 포텐셜 유동에 의해 해석하였다. 프로펠러는 보오텍스 격자법(VLM)을 사용하였고 WIG선은 포텐셜 기저 패널법을 사용하여 각 경계조건을 만족시키면서 반복계산을 통하여 상호작용 및 성능을 해석하였다. 자유수면은 강체로 가정하여 경상법을 사용하였다. 프로펠러-WIG의 상호작용 및 성능을 해석하기에 앞서 발표된 실험결과와 계산결과가 있는 MP101 프로펠러와 MR-21 타의 상호작용 및 성능해석을 수행하여 개발된 프로그램의 정도를 검증하였다. 프로펠러-WIG선의 상호작용해석은 프로펠러의 부착위치, 직경 및 회전수의 변화에 따른 비행고도 높이 변화에 대한 양력 및 피치모멘트를 계산하여 비교하였다. 날개 앞에 부착된 프로펠러는 WIG선의 양력을 급격히 향상시키며 정적안정성을 향상시킴을 알았다. 따라서 적절한 프로펠러의 크기, 부착위치 및 회전수의 선택이 PARWIG선의 성능향상을 위해 필수적임을 알았다.

• 대한조선학회논문집
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• 제47권4호
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• pp.553-564
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• 2010

This paper studies on the rudder shapes for the suppression of the cavitation around a horn-type rudder. To improve the problems due to cavitation, there have been several studies. However, these some studies are recognized as incomplete ways to suppress the rudder cavitation. In this study, the section shapes to suppress the cavitation phenomena are determined by moving the location of maximum thickness for reducing the curvature variation and changing the radius of leading edge. Also, in the pintle part, the curvature radius of the inlet outlet edge of rudder plate is changed. During the design of rudder shape, two-dimensional numerical simulations are firstly performed because those offer some advantages with that cavitation phenomena becomes predictable for a short time, and then the three-dimensional numerical simulations are performed to confirm the determination. The time mean distribution of the propeller slipstream is imposed on the inlet boundary condition. As some results, this paper shows the effects reducing the range of the occurrence of cavitation, and suggests the references on the design of a horn-type rudder for the suppression of cavitation phenomena.

• 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.