• Journal of Navigation and Port Research
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• v.37 no.4
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• pp.345-350
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• 2013

It is well known that the hydrodynamic forces and moments induced by the proximity of bank in confined waters, such as in a harbour or narrow channel affect ship's maneuvering motion. In this paper, the calculation method based on the slender body theory for estimation of the hydrodynamic force between ship and breakwater is applied, and also, the characteristic features of hydrodynamic force acting on a large vessel in the proximity of a breakwater are described and illustrated. Furthermore, the effects of water depth and the lateral spacing between ship and breakwater are summarized and discussed.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1280-1285
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• 2004

Microsystem technology has been applied to space technology and became one of the enabling technology by which low cost and high efficiency are achievable. Micro propulsion system is a key technology in the miniature satellite because micro satellite requires very small and precise thrust force for maneuvering and attitude control. In this paper research on micro solid propellant thruster is reported. Micro solid propellant thruster has four basic components; micro combustion chamber, micro nozzle, solid propellant and micro igniter. In this research igniter, solid propellant and combustion chamber are focused. Micro igniter was fabricated through typical micromachining and evaluated. The characteristic of solid propellant was investigated to observe burning characteristic and to obtain burning velocity. Change of thrust force and the amount of energy loss following scale down at micro combustion chamber were estimated by numerical simulation based on empirical data and through the calculation normalized specific impulses were compared to figure out the efficiency of combustion chamber.

• Journal of Power System Engineering
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• v.13 no.5
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• pp.18-24
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• 2009

This paper shows the result of development about the revolution system of azimuth thruster which of power is less than 250kW for small ship. Advanced Azimuth revolution system can revolve propeller and rudder from 360 degree so that this system for vessel maneuvering can be excellent of propulsion effectively. Fluid power control system for azimuth thruster is designed with PID control system by using CEMTool/SIMTool program. And the actuator used for servo valve can control rudder angle, pressure and direction. The first, We had a test for the angle control of revolution system. The result of angle control confirmed that it has the good efficiency from experiment result of time input degree $30^{\circ}$, $90^{\circ}$ and $180^{\circ}$. The second, We had to a test for the pressure characteristic of hydraulic motor. As a result, We confirmed the maximum pressure 3.5MPa and steady state 0.7MPa nom experiment result of time input degree $30^{\circ}$. In this paper, it is identified the pressure characteristic of hydraulic motor and angle control for azimuth thruster by AMESim, and it has been confirmed the usefulness of AMEsim modeling was verified by comparison between AMESim simulation results and experiments results.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1459-1464
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• 1996

The most important parameter for hydraulic active suspension system is to sustain desirable vehicle maneuvering stability and ride comfort without increasing consumption power. The performance of hydraulic active suspension system depends on damping force of body damping valve and piston damping valve. Hydraulic actuator design and damping valve parameter selection are essential and basic procedure to design hydraulic active suspension system. This paper is on computer simulation with use of mathematical model that was delivered from dynamic characteristic of hydraulic actuator, as know basic damping characteristics of hydraulic active suspension system. The aim of this paper is to select the system parameter that affect mainly hydraulic active suspension, and identify the validity on the system parameter selection.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.4
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• pp.683-692
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• 2002

The most important parameter for hydraulic active suspension system is to sustain desirable vehicle maneuvering stability and ride comfort without increasing power consumption. The performance of hydraulic active suspension system depends on damping force of body damping valve and piston damping valve. Hydraulic actuator design and damping valve parameter selection are essential and basic procedure to design hydraulic system. This paper is on computer simulation with use of mathematical model that was delivered from dynamic characteristic of hydraulic actuator, as know basic damping characteristics of hydraulic active suspension system. The aim of this paper is to select the system parameter that affect mainly hydraulic active suspension, and identify the validity on the system parameter selection.

• Journal of the Society of Naval Architects of Korea
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• v.37 no.2
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• pp.88-99
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• 2000

As a part of theoretical and experimental research works for the prediction and improvement of ship's maneuvering performance, an experimental study for the optimum rudder design has been carried out. Largely, this study is composed of the investigations on three major characteristics which determine rudder performance, that is, the investigations on section shape, planform and aspect ratio, and the investigation on the special section shapes. Some practically useful design directions and conclusion for each characteristic have been derived through this study. Among special section shapes, dolphin-tail type section shape has shown a possibility of significantly improving rudder performance if utilized as the section of rudders.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.4
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• pp.109-115
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• 2011

The ice tank is important facility to check the performance of the ship and offshore in ice condition before the construction. MOERI(Maritime & Ocean Engineering Research Institute) constructed ice model basin on the end of 2010. The ice technology to know the phenomena of ice near the ship and to estimate power of the ship in model scale is the main characteristic of the ice model basin. To achieve this goal in one ice sheet, making of test plan and feasibility check of test possibility have to review in the beginning stage of the every test. This paper describes the number of maximum resistance and self propulsion test in a sheet of level ice and proposes the methodology to optimize pack ice, rubble ice, brash ice and ice ridge test in MOERI ice tank. The feasibility of free running test to know maneuvering performance in ice field and some specific idea to measuring ice thickness and ice ridge shape was proposed.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.48-59
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• 2020

A traditional propeller can easily become entangled with floating objects while operating. In this paper, we present a newly developed Electromagnetic-valve-control-based Water-jet Propulsion System (ECWPS) for an unmanned surface cleaning vessel that can be flexibly controlled via a Micro Control Unit (MCU). The double-structure was adapted to the unmanned surface cleaning vessel for floating-collection missions. Computational Fluid Dynamics (CFD) software for operating effect simulation was also used to reveal the working principle of the ECWPS under different conditions. Neglecting the assembly technique, the design level, controlling strategy, and maneuvering performance of the ECWPS reached unprecedented levels. The ECWPS mainly consists of an Electromagnetic-valve Array (EA), pipeline network, control system, and water-jet source. Both CFD analyses and experimental results show that the hydraulic characteristic of the ECWPS was predicted reasonably, which has enormous practical value and development prospects.

• Journal of the Korean Society of Systems Engineering
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• v.16 no.2
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• pp.110-117
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• 2020

In this paper, we estimated the straight line stability by performing a 3 degree of freedom spiral test simulation of a intact/damaged surface combatant using the hydrodynamic coefficient obtained through the PMM(Planar motion mechanism) test based on system engineering process. A model ship was ONR Tumblehome and damaged compartment was set on the starboard bow. As a result of conducting a spiral test simulation based on the experimental results of J.Ha (2018), the asymmetric straight line stability due to the damaged compartment was confirmed. In the case of a ship in which the starboard bow was damaged, it was confirmed that it had the characteristic to deflect to the left when going straight. Also, when estimating the straight line stability of a both port and starboard asymmetric surface combatant, a separated equation of motion model that sees the port and starboard as different ships seems suitable.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.277-282
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• 2006

The purpose in having a control surface on a ship is to control the motion of the ship. The control surface may be composed entirely of a single movable surface or of a combination of fixed and movable portion A control surface has one sole function to perform in meeting its purpose, and that is to develop a control force in consequence of its orientation and movement relative to the water. The forces and moments generated as a result of this rotation and angle of attack then determine the maneuvering characteristics of the ship. In this paper the study of flapped rudder's 2-dimensional section was accomplished. Model tests had been carried out with different angles of attack of a main foil and flap's deflection angles to predict the performance of the flapped rudder and the 2 frame particle tracking method had been used to obtain the velocity distribution in the flow field $Re=2.8\times10^4$ had been used during the whole experiments and measured results had been compared with each other.