• International Journal of Ocean System Engineering
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• 제3권2호
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• pp.77-89
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• 2013

The propeller performance has been investigated using a benchmark Duisburg Test Case ship with RANSE. First, the hydrodynamic characteristics of propeller in case of open water have been analyzed by a commercial CFD program and the results are compared with those of experimental data. Later, the flow around the bare hull has been solved and the frictional resistance value and form factor of the ship have been obtained and compared with those of ITTC57 formulation and experimental results for validation. The free surface effect has been ignored. A good agreement has been obtained between the results of RANSE and experiments at both stages. Then the ship - propeller interaction problem was solved by RANSE and the differences in thrust, torque and efficiency of propeller as compared with the open-water numerical results have been discussed.

• 수산해양기술연구
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• 제40권2호
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• pp.149-154
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• 2004

본 논문에서는 펌프 노즐이 부착된 잠수 선형의 유동에 관해 수치해석 결과를 보여준다. 이는 속도분포, 양력계수, 영각의 값을 갖는 펌프젯 노즐이 선체와 부착되었을 때와 부착되지 않았을 때의 종강도 모멘트 등의 값들을 계산한다. 선형의 속도 분포에 따른 노즐의 영향면적과 양력계수(변호의 특성요인) 종강도 모멘트, 영각에 따른 도함수 등을 보여준다.

• 대한조선학회논문집
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• 제29권4호
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• pp.132-145
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• 1992

추진 효율 향상을 위한 대칭형 전류 고정날개-프로펠러 추진시스템의 설계, 이론성능해석 및 모형시험 과정을 정리하였다. 프로펠러 후류에서의 회전방향 운동에너지 회수를 통한 추진효율 향상을 도모하기 위하여 프로펠러 전방에 반대방향의 회전 속도를 주기 위한 고정날개를 설치하였다. 모형시험 결과 대칭형 전류 고정날개 추진시스템이 단독프로펠러에 비하여 3%정도 추진효율의 향상이 있음을 확인하였다. 실선 장착시에는 선체 반류에서의 난류 강도증가 및 레이놀드수 증가에 따른 고정날개 표면에서의 박리현상 감소에 의하여 고정날개 항력계수가 감소할 것으로 추정되며 그에 따라 본 추진시스템의 추진효율 증가량이 더욱 커지리라 판단된다.

• 한국전산유체공학회지
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• 제21권1호
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• pp.72-77
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• 2016

In this study, effects of thurster axis tilting angle on the thruster-hull interaction and propulsion performance in a dynamic positioning system of offshore plant are numerically investigated. Straight and 7-degree tilted downward thruster models as a form of ducted propeller are considered. For numerical simulations, Reynolds averaged Navier-Stokes equations with SST turbulence model are solved by using STAR-CCM+. Results show that thruster-hull interaction is reduced in 7-degree tilted thruster model with lower vortex strength between thruster and hull bottom, although the propulsion performance does not have noticeable difference in a bollard condition.

• 해양환경안전학회지
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• 제26권1호
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• pp.15-21
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• 2020

본 연구는 ISO19030 - 선체 및 프로펠러 성능 모니터링 방법을 실선 178 k 벌크선박에 적용한 결과에 관한 것이다. 최근 온실가스 저감 규정 대응과 해운 경쟁력 확보를 위해 에너지 저감 솔루션을 선박에 적용하려는 시도가 증가하고 있다. 하지만 정량적으로 선박 성능을 분석하기 쉽지 않아 에너지 저감 솔루션의 평가가 쉽지 않았다. 이러한 해운 산업의 요구에 따라 2016년 ISO19030이 표준화되어 선박 성능 분석을 정량화할 수 있는 기반이 마련되었다. 하지만 ISO19030에서 제안하는 환경 보정법은 각 날씨 영향을 고려한 보정이 아닌 정수(Calm Sea) 상태에서 운항한 데이터만 분석하는 방식이다. 이러한 분석 방식은 선박의 운항 구간에 따라 데이터가 필터링 되는 편차가 심하고 정확한 환경 보정을 하지 않아 6개월 이하의 분석은 신뢰하기 어렵다. 본 연구에서는 ISO19030을 실제 3척 선박 3년 이상 장기간 운항 데이터에 적용하였다. 적용 결과를 토대로 ISO19030 효용성과 한계점을 파악하고 ISO19030에서 제안하는 필터링 방식 대신 ISO15016의 파도 보정(STA-WAVE2)을 통해 성능 분석 방법을 개선하고자 한다.

• 대한조선학회논문집
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• 제41권3호
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• pp.13-21
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• 2004

This paper deals with a theoretical and experimental method for the design of a biased asymmetric pre-swirl stator propulsion system which is an energy saving device by recovering a propeller rotational energy. In the case of slow-speed ships, the upward flow is generated along the afterbody hull form at the propeller plane. The generated upward flow cancels the rotating flow of the propeller at the starboard part while it increases at port part. The present biased asymmetric pre-swirl stator propulsion system consists of three blades at the port and one blade at the starboard which can recover the biased rotating flow effectively. This paper provides the design concept which gives more simple and a high degree of efficiency and the experimental results for the compound propulsion system.

• 대한조선학회논문집
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• 제50권5호
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• pp.282-290
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• 2013

The effects of the combination of blade number for forward and after propeller on the propeller shaft forces of a contra-rotating propeller (CRP) system are presented in the paper. The research is performed through the numerical simulations based on the Reynolds-Averaged Navier-Stokes equations (RANS). The simulation results of the present method in open water condition are validated comparing with the experimental data as well as the other numerical simulation results based on the potential method for 4-0-4 CRP (3686+3687A) and 4-0-5 CRP (3686+3849) of DTNSRDC. Two sets of CRP are designed and simulated to study the effect of the combination of blade number in behind-hull condition. One set consists of 3-blade and 4-blade, while the other is 4-blade and 4-blade. A full hull body submerged under the free surface is modeled in the computational domain to simulate directly the wake field of the ship at the propeller plane. From the simulation results, the fluctuations of axial force and moment are dominant in the case of same blade numbers for forward and after propellers, whereas the fluctuations of horizontal and vertical forces and moments are very large in the case of different blade numbers.

• 대한조선학회논문집
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• 제40권5호
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• pp.17-25
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• 2003

Velocity field behind a container ship model with a rotating propeller has been investigated using PIV (particle image velocimetry) system. Four hundred instantaneous velocity fields were measured at 4 different blade phases and ensemble-averaged to investigate the spatial evolution of vortical structure of near wake within one propeller diameter downstream. The phase-averaged mean velocity fields show the potential wake and the viscous wake formed due to the boundary layers developed on the blade surfaces. The interaction between bilge vortex developed along the hull surface and the tangential velocity component of incoming flow causes to have asymmetric flow structure in the transverse plane.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권2호
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• pp.899-913
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• 2019

In order to provide a complementary perspective to the effects of the maneuvering motions on the unsteady propeller performance, the numerical simulation of the flow field of the hull-rudder- propeller system is performed by Unsteady Reynolds-averaged Naiver-Stokes (URANS) method. Firstly, the flow fields around the submarine model without the presence of propeller in straight ahead motion and the steady diving maneuvers with submergence rudder deflections of 4°, 8° and 12° are predicted numerically. The non-uniformity characteristic of the nominal wake field is exacerbated with the increase submergence rudder angle. Then the flow field around the SUBOFF-G submarine fitted with the 4381 propeller is simulated. The axial, transverse and vertical unsteady propeller forces in different maneuvering conditions are compared. In general, as the submarine maneuvers more violently, the harmonic amplitudes of the unsteady force at the 2BPF and 3BPF increased more significantly than that at BPF.

• 수산해양기술연구
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• 제43권3호
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• pp.222-231
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• 2007

This paper represents a basic statistical examination on the navigability of ocean-going ship from the point of estimating the time lasting period when propeller racing occurred by using the basic probability theory and the statistics. The propeller racing is one of the most important seakeeping qualities in relation to the safety of the main engine and shafting system. The trend of the racing has been mainly investigated in order to estimate allowable maximum propeller diameter, operation of ocean-going ships, etc.. In those studies, the propeller racing generally and mainly 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 of propeller racing have been examined as a principal subject of study as usual. However, the time during which the amplitude exceeds the depth of point, that is, the propeller exposes in the air, must be also one of most important factor affecting the trend of propeller racing. Then, this paper proposes a new practical method for estimating the time lasting of exposed propeller related to propeller racing in rough-confused seas on the basis of the linear strip theory and the statistics. And, numerical examples of estimating the propeller racing probability are given for four wide ship forms. Finally the usefulness of the proposed method for predicting propeller racing based on the time lasting period is discussed.