• 제목/요약/키워드: Free Running Model Ship

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횡경사상태 선박의 조종성능변화에 관한 실험적 연구 (An Experimental Study on the Manoeuvrability of a Ship in Heeled Condition)

  • 윤근항;여동진
    • 대한조선학회논문집
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    • 제56권3호
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    • pp.273-280
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    • 2019
  • Predicting ship manoeuvrability is attracting widespread interest in the field of analyzing maritime accident to simulate a highly accurate track of a ship in abnormal accident situations. This study investigated the manoeuvrability of a ship in abnormally heeled condition. Free Running Model Tests (FRMT) with 1/65.83 scaled KCS (KRISO container ship) were conducted in three heeled conditions; $35^{\circ}$ turning circle tests and 20/20 zigzag manoeuvring tests were conducted in $0^{\circ}$, $-10^{\circ}$, and $-20^{\circ}$ conditions. The test results showed that the heeled to port condition significantly affected starboard turning and zigzag characteristics; the tactical diameters in the turning circle tests decreased, and the first overshoot angles in the zigzag tests increased when the ship was in the larger heeled condition. These results indicate that the roll angle of the ship considerably affects yaw rate and speed decrease of the ship. The turning and zigzag indices from trajectory and navigation data in the study were provided for benchmark data sets.

1/42.0 KCS 모형선의 조종성능에 관한 연구 (A Study on the Manoeuvrability of 1/42.0 Scaled KCS)

  • 윤근항;김동진;연성모;김유철;김연규;양경규
    • 대한조선학회논문집
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    • 제59권5호
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    • pp.262-270
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    • 2022
  • The emergence of new concept ships, such as autonomous ships, has drawn much attention on the manoeuvrability of ships because of the safe navigation and operation of ships. Although the manoeuvrability of KRISO Container Ship(KCS) has been frequently reported, there have been few documents of representative manoeuvre cases conducted in various methods by one institute. This paper presents the manoeuvrability of the ship in 1/42.0 model scale by 3 methods: free running model tests, horizontal planar motion mechanism tests, and computational fluid dynamics analysis. KRISO reports KCS manoeuvre data: 35° turning circle tests and 20/20(10/10) zigzag manoeuvring tests. In addition, a simple formula for integrating and comparing manoeuvre indices, Manoeuvrability Comparing Simple Index(MCSI), is proposed.

쌍축선의 정적 횡경사각에 따른 조종성능 변화에 관한 실험적 연구 (An Experimental Study on the Change in Manoeuvring Performance According to the Static Heel Angle of a Twin-Screw Ship)

  • 권창섭;윤근항;여동진
    • 대한조선학회논문집
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    • 제58권6호
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    • pp.407-414
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    • 2021
  • The manoeuvrability of a ship with an unwanted heel angle due to a maritime accident is changed from the original characteristics. The purpose of this study is to quantitatively investigate the change in the manoeuvring performance of a twin-screw ship under various hee angles and speed conditions. A series of free running model test campaigns were performed in the Ocean Engineering Basin of Korea Research Institute of Ships & Ocean Engineering (KRISO) for a twin-screw car ferry vessel. Turning circle test and zig-zag 10/10 and 20/20 tests were carried out on the heel angles of 0, -10, and -19.5 degrees. In addition, two-speed conditions were considered to understand the effect of ship speed. In order to examine the effect of the bilge keel, a heel angle of -22 degree where the bilge keel is exposed outside the water surface, was considered. Finally, the change of manoeuvring characteristics according to the heel angle for a twin-screw and a single-screw vessel is discussed.

Low energy ultrasonic single beacon localization for testing of scaled model vehicle

  • Dubey, Awanish C.;Subramanian, V. Anantha;Kumar, V. Jagadeesh
    • Ocean Systems Engineering
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    • 제9권4호
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    • pp.391-407
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    • 2019
  • Tracking the location (position) of a surface or underwater marine vehicle is important as part of guidance and navigation. While the Global Positioning System (GPS) works well in an open sea environment but its use is limited whenever testing scaled-down models of such vehicles in the laboratory environment. This paper presents the design, development and implementation of a low energy ultrasonic augmented single beacon-based localization technique suitable for such requirements. The strategy consists of applying Extended Kalman Filter (EKF) to achieve location tracking from basic dynamic distance measurements of the moving model from a fixed beacon, while on-board motion sensor measures heading angle and velocity. Iterative application of the Extended Kalman Filter yields x and y co-ordinate positions of the moving model. Tests performed on a free-running ship model in a wave basin facility of dimension 30 m by 30 m by 3 m water depth validate the proposed model. The test results show quick convergence with an error of few centimeters in the estimated position of the ship model. The proposed technique has application in the real field scenario by replacing the ultrasonic sensor with industrial grade long range acoustic modem. As compared with the existing systems such as LBL, SBL, USBL and others localization techniques, the proposed technique can save deployment cost and also cut the cost on number of acoustic modems involved.

빙 해역에서 유조선의 조종 모형시험에 대한 연구 (Maneuvering Experiments in Ice on a Single Screw Tanker)

  • 김현수
    • 대한조선학회논문집
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    • 제45권5호
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    • pp.495-501
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    • 2008
  • Samsung Heavy Industries (SHI) and NRC's Institute for Ocean Technology (IOT) collaborated on a project to predict the performance of a new design for a Suezmax size tanker that had acceptable open water performance but was also capable of operating in ice. The resulting hull form was a single screw, single rudder design with a bulbous bow, modified for operation in ice. An important design consideration is the ability of the ship to maneuver in different ice conditions. This paper presents the results of maneuvering experiments in pack ice and level ice, using a free running model.

Planar Motion Mechanism Test of the Mobile Harbor Running in Design Speed in Circulating Water Channel

  • Yoon, Hyeon-Kyu;Kang, Joo-Nyun
    • 한국항해항만학회지
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    • 제34권7호
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    • pp.525-532
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    • 2010
  • Mobile Harbor (MH) is a new transportation platform that can load and unload containers onto and from very large container ships at sea. It could navigate near harbors where several vessels run, or it could navigate through very narrow channels. In the conceptual design phase when the candidate design changes frequently according to the various performance requirements, it is very expensive and time-consuming to carry out model tests using a large model in a large towing tank and a free-running model test in a large maneuvering basin. In this paper, a new Planar Motion Mechanism(PMM) test in a Circulating Water Channel (CWC) was conducted in order to determine the hydrodynamic coefficients of the MH. To do this, PMM devices including three-component load cells and inertia tare device were designed and manufactured, and various tests of the MH such as static drift test, pure sway test, pure yaw test, and drift-and-yaw combined test were carried out. Using those coefficients, course-keeping stability was analyzed. In addition, the PMM tests results carried out for the same KCS (KRISO container ship) were compared with our results in order to confirm the test validity.

저속시 선체에 작용하는 조종유체력 및 조종성능에 관한 연구 (Hydrodynamic Forces and Manoeuvring Characteristics of Ships at Low Advance Speed)

  • 손경호
    • 한국항해학회지
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    • 제15권4호
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    • pp.27-39
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    • 1991
  • 출발, 정지, 후진, 가속, 감속 등을 포함하는 저속 항행시의 조종운동을 예측하기 위해서, 선체, 프로펠러, 타에 작용하는 유체력의 특징을 검토하여 이를 수식모델화 하였으며, 제안된 수식모델을 이용하여 유조선, 가스운반선 두 선박에 대해 저속시의 조종운동 시뮬레이션 계산을 수행하여 실험결과와 비교 검토하였다

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GM 및 종경사 변경에 따른 선박의 조종성능변화에 관한 실험적 연구 (An Experimental Study on the Manoeuvrability of a Ship in Different GM and Trim Conditions)

  • 윤근항;김동진;여동진
    • 대한조선학회논문집
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    • 제57권4호
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    • pp.230-240
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    • 2020
  • The aim of this study was to investigate the manoeuvrability of a ship in different Center of Gravity (CG) conditions. Free Running Model Tests (FRMT), such as 35°turning circle tests, 20/20 zigzag manoeuvring tests, and 10/10 zigzag manoeuvring tests, were conducted in three GM and three trim conditions with 1/65.83 scaled KRISO Container Ship (KCS). The test results indicated that KCS in the lower GM condition and the trim by bow condition showed reduced advance and tactical diameter in turning circle tests and increased overshoot angles in zigzag tests, and those manoeuvring indices were strongly related with roll angle. In addition, sensitivity indices for three-axis CG position were suggested with prior research, and it showed that y-axis CG position significantly affected manoeuvrability of KCS due to the low GM. Therefore, in the case of KCS, it is evident that the roll angle during manoeuvre is closely related with manoeuvring indices.

저속시 선체에 작용하는 조종유체력 및 조종성능에 관한 연구 (Hydrodynamic Forces and Maneuvering Characteristics of Ships at Low Advance Speed)

  • 손경호
    • 대한조선학회논문집
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    • 제29권3호
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    • pp.90-101
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    • 1992
  • 선박이 일정속도 이상의 전진속도를 갖일 때의 조종성능 평가법은 지금까지 많이 제안되어 왔으나, 이들을 항만내에서의 다양한 운동모드 즉, 출발, 정지, 후진, 미속조종 등에는 적용에 무리가 있다. 본 연구에서는 출발, 정지, 후진, 미속조종 등을 포함하는 저속항행시의 조종운동 특성의 평가법을 제안하기 위해서, 대각도 횡류각 뿐만 아니라 광범위한 프로펠러 작동하에서의 선체, 프로펠러, 타에 작용하는 유체력의 특성을 수식모형화 하였다. 제안된 수식모형을 이용하여 액화가스 운반선, 대형유조선 두 선박에 대해 저속항행시의 조종운동 시뮬레이션 계산을 수행하여 실선시험 또는 모형시험 결과와 비교, 검토하였다.

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고속 활주선의 선형에 따른 저항 성능 및 규칙파 중 운동 성능 고찰 (Effects of Hull Form Variations on Resistance and Seakeeping Performance of Planing Hulls with and without Incoming Regular Waves)

  • 김동진;김선영;김성환;서정화;이신형
    • 대한조선학회논문집
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    • 제51권5호
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    • pp.369-379
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    • 2014
  • Planing hull forms have significant influences on those hydrodynamic performances in calm water and in waves. Therefore, the hydrodynamic performance of a planing vessel should be predicted by model tests or theoretical calculations, and be confirmed whether it shows the performance requirements at the design stage. In this study, four planing hull forms are designed with the goal of the improvement of resistance and seakeeping performance, and 1/6.5 scale model tests are carried out in Seoul National University towing tank. The effects of design parameters such as length-to-beam ratio, deadrise angle and forebody shape on the hydrodynamic performance are investigated, based on model test results. Running attitude and resistance of model ships in calm water are also estimated by empirical formulae proposed by Savitsky (1964; 2007; 2012), and compared with the model test results. It is shown that calm water performance of non-prismatic planing hulls can be predicted well by Savitsky (2012)'s formula which improves the original Savitsky(1964/2007)'s formula by taking into account the variations of deadrise angles, and the actual angles between the hull bottom and the free surface.