• Title/Summary/Keyword: 횡동요

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Rolling Motion Simulation in the Time Domain and Ship Motion Experiment for Algorithm Verification for Fishing Vessel Capsizing Alarm Systems (어선전복경보시스템 알고리즘 검증을 위한 어선 횡동요 시험 및 시간영역 횡동요 시뮬레이션)

  • Yang, Young-Jun;Kwon, Soo-Yeon
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.23 no.7
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    • pp.956-964
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    • 2017
  • This study contributes to deepening understand of the characteristics of fishing vessel rolling motions to improve the development of capsizing alarm systems. A time domain rolling motion simulation was performed. In order to verify capsizing alarm systems, it is necessary to carry out experiments assuming a capsizing situation and perform actual fishing vessel measurements, but these tasks are impossible due to the danger of such a situation. However, in many capsizing accidents, a close connection with rolling motion was found. Accordingly, the rolling motion of a fishing boat, which is the core of a fishing vessel capsizing alarm system, has been accurately measured and a time domain based on a rolling motion simulation has been performed. This information was used to verify the algorithm for a capsizing alarm system. Firstly, the characteristics of rolling motion were measured through a motion experiment. For small vessels such as fishing vessels, it was difficult to interpret viscosity due to analytical methods including CFD and potential codes. Therefore, an experiment was carried out focusing on rolling motion and a rolling mode RAO was derived.

Roll Damping Moment of a Small Fishing Vessel by Free Rolling Test in Calm Water (평수중 자유 횡동요 시험에 의한 소형어선의 횡동요 감쇠모멘트에 관한 연구)

  • H.H. Chun;S.H. Chun;S.Y. Kim
    • Journal of the Society of Naval Architects of Korea
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    • v.37 no.1
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    • pp.1-9
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    • 2000
  • The roll damping characteristics of the three models of a 3 ton class fishing vessel such as the bare hull, hull with bilge keels, and hull with bilge keels and a central wing are investigated by the free roll tests in calm water in a towing tank with the variations of the forward speed, initial angle and OG. The experimental results are compared with the numerical results of mathematical modellings by the energy method for these three models and the energy dissipation patterns are also compared.

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A Study on the Statistical Characteristics of Rolling Motion of Ships Using Multiple Time Scales (다중 시간법에 의한 선박 횡동요 응답의 통계적 특성 연구)

  • Yun-Cheol Na;Sun-Hong Kwon;Dong-Dai Ha
    • Journal of the Society of Naval Architects of Korea
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    • v.31 no.1
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    • pp.102-110
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    • 1994
  • The roll response of ships to the narrow band random exciting moment is investigated based on the multiple time scale technique. The results are compared with those calculated from statistical equivalent linearization method. The calculation results have shown that the results calculated from multiple time scale technique eve wider range of multiple values. Numerical simulations of rolling motion of ship are performed to confirm the results.

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Development of Apparatus for Pure Roll-Motion Test of Underwater Vehicles (수중운동체의 순수 횡동요 시험 기구 개발)

  • Kim, Dong-Hwi;Baek, Hyung-Min;Lee, Seung-Keon;Kim, Eun-Soo
    • Journal of Navigation and Port Research
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    • v.45 no.1
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    • pp.16-25
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    • 2021
  • Hydrodynamic coefficients should be accurately estimated to predict the maneuverability of underwater vehicles. Various captive model tests have been performed as part of estimation methods for these coefficients. Estimating hydrodynamic coefficients related to roll motion is important because underwater vehicles are sensitive to changes of roll moment. In this research, a pure roll motion equipment was newly designed to simply estimate hydrodynamic coefficients with respect to roll motion. Roll motion was implemented through a brief mechanical mechanism. The principle of operation, application process, and system identification of the equipment are described. An analysis method of the pure roll test is also suggested. Repeated tests of the newly equipment were carried out to check its reproducibility.

A Study on the Performance of Active Anti-Rolling Tank Stabilizer System (능동형 횡동요 감쇠장치의 성능에 관한 연구)

  • Choi, Chan-Moon;Ahn, Jang-Young;Lee, Chang-Heon
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.40 no.2
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    • pp.138-143
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    • 2004
  • This experimental paper deals with the performance of tanks that are turned the active A.R.T(Anti-Rolling Tank) when the fluid transfers from wing tank to the opposite tank by the power developed by the automatic control system (INTERING Stabilizer), which was installed in the fishery training ship T/S. A - RA (G/T:990 tons) of Cheju National University. In this paper, the author has tested the performance of INTERING Stabilizer for the signals obtained by the inclinometer in irregular waves and compared with the results obtained in passive mode operation at stop and at various ship speeds. The performances of the system were confirmed the results as follows through the tests: 1. The average amplitude and significant roll (${\pi}$1/3) of the passive and active mode operations in the condition of stoped engine and underway were obtained 8.30$^{\circ}$, 4.37$^{\circ}$, 8.30$^{\circ}$, 4.37$^{\circ}$, and 5.01$^{\circ}$, 4.36$^{\circ}$, 5.50$^{\circ}$, 5.10$^{\circ}$, respectively. 2. The rates of performance of active mode operations were carried out during a sea trial in the condition of stop engine and underway resulted in 47.5%, 12.7%, respectively, therefore the active mode operation estimated to be improved more than passive mode operation. 3. Active - A.R.T by INTERING Stabilizer didn't affect the amplitude of pitching.

Roll Damping Moment of a Small Fishing Vessel by Free Rolling Test in Waves (파랑중 자유 횡동요 시험에 의한 소형어선의 횡동요 감쇠모멘트에 관한 연구)

  • H.H. Chun;S.H. Chun;S.Y. Kim
    • Journal of the Society of Naval Architects of Korea
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    • v.37 no.2
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    • pp.30-37
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    • 2000
  • The roll damping characteristics of the three models of a 3ton class fishing vessel, that is the bare hull, hull with bilge keels, and hull with bilge keels and a central wing are investigated by the free roll tests in head waves in a towing tank with the variations of the forward speed, initial angle and OG. The wave length variations are also included. The experimental results are compared with the numerical results of mathematical modellings by the energy method for these three models and the energy dissipation patterns are also compared. The roll damping speed increases, the effect of the waves on the roll damping of the models with the additional devices is negligible due to the much increased damping caused by the lift increase.

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Responses of a roll-pitch coupled nonlinear system to the primary resonance of the roll mode (횡동요 모드와 주공진 된 횡-종동요연성 비선형계의 응답)

  • 오일근
    • Journal of Ocean Engineering and Technology
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    • v.11 no.3
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    • pp.107-115
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    • 1997
  • 비성형 동력학계로 모델링된 부유수송체의 동적응답을 조사하고 그 운동의 안정성을 해석하였다. 종동요 모우드의 고유주파수가 횡동요 모우드의 고유주파수의 두배가 되는, 즉, 2:1 내부공진 혹은 자기계수공진인 조건하에서, 이부유수송체는 한 운동 모우드의 직접가진에 의해 간접가진된 다른 모우드가 대진폭 응답을 보일 수 있음을 밝혔다. 또항, 종동요 모우드의 감쇠력은 비교적 넓은 범위의 운동에 대해 선형적임에 반해, 횡동요 모우드의 감쇠력은 점성의 영향이 대단히 커서 비선형성이 대단히 강한 것으로 알려져 왔다. 이 문제를 수학적으로 모델링하기 위하여, 종동요 모우드의 운동방정식에는 선형및 제곱형의 합의 형태인 감쇠력 모형을 사용하였다. 다중척도법을 사용하여 이 두가지 운동 모우드의 주기적 응답및 그의 안정성에 미치는 제곱형 비선형 횡동요 감쇠력의 영향을 밝혔다. 조우주기가 횡동요 모우드의 고유주기와 근사한 경우에 대하여 이 비선형계의 응답을 구하고 주파수-응답 곡선으로 나타내었다.

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실 해상모형시험을 이용한 선미 보조동체 장착 Stepped hull 선형의 횡동요 및 저항특성 비교 연구

  • Jo, Hyo-Je;Son, Gyeong-Ho;Park, Chung-Hwan
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • pp.37-39
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    • 2007
  • 고속 활주형선의 선형시험 ${\cdot}$ 검증을 위하여 설 해상모형시험기법을 정립하였으며, 본 시험법을 이용하여 선미 보조동체 장착 유무에 따른 고속 Stepped Hull 선형의 횡동요 및 저항특성을 비교, 분석하였다.

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A Study on Development of an Anti-Rolling System for the Ship Stability Improvement (선박안정성 향상을 위한 횡동요 방지 장치 개발에 관한 연구)

  • Kim, Young-Bok;Lee, Kwon-Soon;Kim, Jun-Hyo;Chae, Gyu-Hoon
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.11 no.1
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    • pp.23-28
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    • 2005
  • We have investigated the usefulness cf active stabilizing system to reduce ship rolling under disturbances, using varying reaction cf the flaps. In the proposed anti-rolling system for a ship, the flaps as the actuator are installed on the stem to reject rolling motion induced by disturbances like wave. The action induced by flaps which depends on power of disturbances am take the ship balance. Especially, in this study we identify the controlled system under the undefined system structure using spectral analysis and experimental studies. Based on these informations, we design the controller to evaluate the usefulness of the proposed system.

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능동형 횡동요 감쇠장치의 효능에 관한 연구

  • 최찬문;안장영;서두옥
    • Proceedings of the Korean Society of Fisheries Technology Conference
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    • pp.83-86
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    • 2003
  • 선박은 근본적으로 파랑이 향상 존재하는 해상에서 운항하게 되므로 파랑 중에서의 선체운동 여객, 승무원, 화물 및 선박 자체의 안전과 밀접한 관계를 가지게 된다. 뿐만 아니라 선박의 운동은 해상에서의 각종 활동과 임무수행의 정도를 결정하는 주요한 인자가 되고 있다. 횡동요(Rolling)는 6 자유도 운동 가운데에서 가장 중요한 운동이며, 선박들이 근본적으로 횡동요에 대하여 낮은 감쇠특성을 갖고 있기 때문에 안정성 측면에서 볼 때에 가장 많이 제어되어 왔다. (중략)

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