• International Journal of Naval Architecture and Ocean Engineering
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• 제16권
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• pp.100599.1-100599.16
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• 2024

The present study concerns validation of data-driven modeling for ship dynamics from free-running model test results, in terms of estimation of hydrodynamic force and moment, maneuvering coefficients, and maneuver simulation results. An estimation method for the hydrodynamic force and moment from the acceleration of a surface combatant model ship is suggested and compared with the conventional ship dynamics modeling. The hull dynamics modeling relates the motion and hydrodynamic force and moment is developed by optimizing maneuvering coefficients which leads to minimum loss function of hydrodynamic force and moment and maneuvering criteria. The maneuvering coefficients of the dynamics model is compared with a conventional system-based dynamics model. Lastly, the maneuvering simulation results are compared to the free-running model test results. The suggested model adequately predicts hydrodynamic force and moment in highly coupled sway and yaw motion.

• 한국항해항만학회지
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• 제33권9호
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• pp.603-608
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• 2009

In this paper, a 3m-class free running model ship will be introduced with its manoeuvring performance experiments. The results of turning circle test and zig-zag test will be explained. The developed system are equipped with GPS, main control computer, wireless LAN, IMU (Inertial Measurement Unit), self-propulsion propeller and driving rudder. Its motion can be controlled by RC (Radio Control) and wireless LAN from land based center. Automatic navigation is also available by pre-programmed algorithm. The trajectory of navigation can be acquired by GPS and it provides us with important data for ship's motion control experiments. The results of manoeuvring performance experiment have shown that the developed free running model ship can be used to verify the test of turning circle and zig-zag. For next step, other experimental researches such as ship collision avoidance system and automatic berthing can be considered in the future.

• 대한조선학회논문집
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• 제60권6호
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• pp.450-459
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• 2023

According to Korea Maritime Safety Tribunal, there have been 14,100 maritime accidents from 2017 to 2021. Among those accidents, ship collision accidents have been up to 1,275 cases. But in the accidents relating to small ships like a fishing vessel, analyzing the causes of the accidents would depend on statements of the persons related because there is often no navigational data. But those statements can be incorrect and give rise to disagreements between them so that it causes conflicts with each other during the trial. So a replay system of ship collision accident (RESCA) has been developed in order to reproduce the ship collision accident by using AIS, V-PASS or radar data. But the reproduced trajectory of ship collision accident is needed to be verified because it can be unreasonable physically. So a method to verify the reproduced trajectory and collect the physical data on ship collision accident is newly designed by using free running test. In the RESCA, the accident is reproduced using the navigational data from the trajectory for a ship and measured from free running model test for the other ship at the same time. Through free running test, the behavior of the model ship is transformed from model scale into real scale. In order to check into the accuracy of the new method, free running model tests by using RESCA are carried out on the actual ship collision accidents.

• 대한조선학회논문집
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• 제57권5호
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• pp.262-270
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• 2020

An outdoor free-running model test system was designed for assessing ship maneuverability with test uncertainty. The test model was a surface combatant of tumblehome hull geometry. The straight forward tests were conducted first to obtain the relationship between the propeller revolution rate and advance speed. During the outdoor tests, the propeller revolution rate to achieve a certain Froude number condition was higher than that in the indoor free-running model tests. Turning circle and zigzag tests for evaluating ship maneuverability criteria were carried out at the propeller revolution rate determined by the straight forward test results. The random and systematic standard uncertainties of maneuvering criteria were obtained by repeated tests and comparison with the indoor free-running model test results, respectively. The test uncertainty was largely dominated by the systematic standard uncertainty, while the random standard uncertainty was small with good repeatability.

• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.466-477
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• 2021

There are three different well-known methods for predicting the manoeuvrability of ships: (1) free running model test, (2) direct manoeuvring simulation using CFD and (3) system-based manoeuvring simulation. In this paper, the manoeuvrability of the KVLCC2 was estimated using CFD with rigid body motion and body force propeller method. The free running manoeuvre at the different time steps were also simulated. The yaw checking ability and the turning ability of KVLCC2 were predicted using CFD and could have been confirmed that the IMO criteria was satisfied. When the results were compared with the model test and system-based method, the free running simulation showed better agreement to that of the model test. It could also be confirmed that the results vary depending on the time step. Overall, the CFD results using the body force propeller method estimated most accurately the test results.

• 대한조선학회논문집
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• 제61권6호
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• pp.508-516
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• 2024

In this paper, free running model tests under surface condition were conducted on the BB2 submarine to estimate its maneuverability performance. The model ship used for the tests was constructed with a modular internal frame design. The internal frame modules can be rearranged and assembled as needed, allowing for adjustments in the model ship’s weight distribution. The center of gravity and buoyancy of the model ship were calculated using 3D design tool to include the effects of water entry. The free running tests comprised turning, zigzag, and spiral tests. The results of each test showed that the BB2’s hull possesses excellent maneuvering performance.

• 대한조선학회논문집
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• 제45권3호
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• pp.247-257
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• 2008

In this paper, a free running system, which is developed recently for a 2m-class ship models, will be introduced. For the remote control of hardware, GUI of software packages was developed using Visual Basic 6.0, and Host PC with Positioning Board manages Servo drive. Then the drive operates propeller and rudder. Its control performance will be shown. Also its adaptability to the resistance, manoeuverability and seakeeping model tests will be considered through the installation on a KTTC standard ship model from MOERI.

• 대한조선학회논문집
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• 제48권3호
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• pp.267-274
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• 2011

This paper presents the results of prediction of maneuverability of KCS about 4 degree of freedom(DOF) including roll motion. The prediction is carried out by CPMC captive model test. The CPMC(Computerized Planar Motion Carriage) with captive model test equipment including roll moment gage is installed at Ocean Engineering Tank of MOERI. KCS is the container ship open to the world by MOERI. To predict the 4 DOF maneuverability of a ship some tests with roll angle are conducted. And the prediction results of maneuverability by simulation are compared with the results of free running model test. The simulation results agree well with those of free running model tests.

• 대한조선학회논문집
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• 제51권5호
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• pp.349-355
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• 2014

The resistance test of a high speed craft such as planing ship is performed with a high speed towing carriage instead of ordinary towing carriage because of the speed limitation. In the resistance test using high speed towing carriage, the model ship is fixed to the carriage to restrain the running attitude for enough measuring time. Such method is called fixed model test method. In the fixed model test method, to get the appropriate running attitude, the model test is iteratively repeated until the trim moment and lift force are close to zero. In this research, trim free model test method is investigated to reduce the number of iteration. And, the limitation of towing speed range in the trim free model test method is investigated.

• 대한조선학회논문집
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• 제62권3호
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• pp.210-217
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• 2025

This paper addresses one of the methods to estimate the maneuverability of underwater vehicles, specifically the free-running model test. An underwater vehicle snorkeling near the surface is affected by environmental factors such as waves and free-surface effects, which influence the vehicle's depth keeping ability and manoeuvring performance. Therefore, precise dynamic analysis on the vehicle near the surface is strongly required. To predict maneuverability, new free-running systems for underwater vehicles, applicable to 1-ton-class models, have been developed, and a model testing procedure for underwater vehicles was established using the systems and BB2 model. Based on the established procedure, manoeuvre tests, including depth changing and keeping performance tests using a practical depth control algorithm, horizontal turning tests, and zigzag tests, were conducted. The manoeuvre test results are presented with detailed data and pictures. The testing method and benchmark data obtained from this study will be used for the design and manoeuvre performance evaluation of various underwater vehicles in the future.