• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 학술대회
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• pp.14-17
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• 2008

Recently, several advanced flow visualization techniques such as Particle Image Velocimetry (PIV) including stereo PIV, holographic PIV, and dynamic PIV have been developed. These advanced techniques have strong potential as the experimental technology which can be used for verifying numerical simulation. In addition, there would be indispensable in solving complicated thermo-fluid flow problems not only in the industrial fields such as automotive, space, electronics, aero- and hydro-dynamics, steel, and information engineering, but also in the basic research fields of medical science, bio-medical engineering, environmental and energy engineering etc. Especially, NT Nano Technology) and BT (Bio Technology) strongly demand these advanced measurement techniques, because it is difficult for conventional methods to observe most complicated nano- and bio-fluidic phenomena. In this paper, the basic principle of these advanced visualization techniques and their practical applications which cannot be resolved by conventional methods, such as flow in automotive HVAC system, ship and propeller wake, three-dimensional flow measurement in micro-conduits, and flow around a circulating cylinder will be introduced.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년 추계학술대회논문집
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• pp.14-17
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• 2008

Recently, several advanced flow visualization techniques such as Particle Image Velocimetry (PIV) including stereo PIV, holographic PIV, and dynamic PIV have been developed. These advanced techniques have strong potential as the experimental technology which can be used for verifying numerical simulation. In addition, there would be indispensable in solving complicated thermo-fluid flow problems not only in the industrial fields such as automotive, space, electronics, aero- and hydro-dynamics, steel, and information engineering, but also in the basic research fields of medical science, bio-medical engineering, environmental and energy engineering etc. Especially, NT (Nano Technology) and BT (Bio Technology) strongly demand these advanced measurement techniques, because it is difficult for conventional methods to observe most complicated nano- and bio-fluidic phenomena. In this paper, the basic principle of these advanced visualization techniques and their practical applications which cannot be resolved by conventional methods, such as flow in automotive HVAC system, ship and propeller wake, three-dimensional flow measurement in micro-conduits, and flow around a circulating cylinder will be introduced.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1992년도 춘계학술발표회 한국항해학회
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• pp.21-43
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• 1992

The recently-developed automated vessels require a system which evaluates the operating condition of the ship at present position form weather information as well as sensors; forecasts the operation condition the sea state to come in foreseeable future ; and suggests the optimum course and speed for ship's sa-fety. According to a study deck wetness propeller racing slamming rolling vertical acceleration lateral acce-leartion vertical bending moment at midship etc. were chosen as the factors for evaluating seakeeping per-formance. As a mater of fact there is no developing the hardware of a system which could consider all the factors onseakeeping performance. This study introduces a theoretical method which makes it possible to evaluate the seakeeping perfor-mance byapplying a theory from reliability engineering and thereby establishing a safety space. lation of stochastic processes with the factors presently adopted for evaluating sekakeeping performance. and develops the overall eseakeeping performance evaluation system in consideration of the safety of human being cargoes and the ship This method of evaluation shall be of much use in developing the practical system of seakeeping perfor-mance of a ship in waves.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2171-2175
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• 2002

Helicopter dynamics are plenty of nonlinearity. A complete mathematical model including propeller dynamics and fortes generated by the propellers is very difficult to obtain. So the method used to design to design a controller is a parameter estimation. Design controller based on variable structure system. This paper deals with LQR control technique to control efficiently, its elevation angle and azimuth one. The purpose of the experiment is to design a controller allows to use a desired elevation angle and azimuth ones. The system model has a helicopter model with 2-degree-of freedom. The simulation results were verified usefulness of controller.

• 한국해양공학회지
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• 제29권2호
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• pp.111-119
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• 2015

In the initial ship design stage, performance predictions are generally carried out before and after the hull form design. The former is based on the main dimensions and power information, and the latter is based on the geometry of the hull form and propeller. This paper deals with the practical application of neural networks for the prediction of a ship's performance factors before and after the hull form design. For this, the hull form parameters that affect the performance are studied, and an optimal neural network structure based on the SSMB database is constructed. By comparing the results predicted by neural networks and the model test results, we confirmed that neural networks can be applied to practically evaluate the performance in the initial ship design stage.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 1999년도 유체기계 연구개발 발표회 논문집
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• pp.252-256
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• 1999

In this research, the performance predictions of the submersible mixer were investigated. The variation of the performance characteristics by changing the impeller design parameters were discussed through the flow calculation results by using a commercial program, FLUENT. The performance of the submersible mixers is related to the velocity diffusion profiles downstream of the impeller and also the required input motor power to mix the fluid. In this study, the various design parameters such as the number of blade, the hub and tip diameters, the impeller blade profiles and revolution speed of the blades were taken for the fixed values. The blade sweep direction, the chord length distribution along with the radius of the blade and the inlet blade angle were changed to make different testing models. The flow calculation results show the effect of the changed design parameters on the performance of the submersible mixers and also give some helpful information for designing more efficient submersible mixers.

• 한국항해학회지
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• 제16권1호
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• pp.14-35
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• 1992

The recently-developed automated vessels require a system which evaluates the operating conditions of the ship at present position from weather information as well as sensors ; forecasting the operations condition in the state to come in foreseeable future ; and suggests the optimum course and speed for ship's safety. According to a study, deck wetness, propeller racing, slamming. rolling, vertical acceleration, lateral acceleration, vertical bending moment at midship etc. were chosen as the factors for evaluating seakeeping performance. As a matter of act, there is no developing the hardware of a system which could consider all the factors on seakeeping performance. This study introduces a theoretical method which makes it possible to evaluate the seakeeping performance by applying a theory from reliability engineering, and thereby establishing a safety space. The author adopts rolling and pitching as the factors on seakeeping performance by clarifying the correlation of stochastic processes the factors presently adopted for evaluation system in consideration of the safety of human being, cargoes and the ship. This method of evaluation shall be of much use in developing the practical system of seakeeping performance of a ship in waves.

• Journal of Ship and Ocean Technology
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• 제12권2호
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• pp.16-31
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• 2008

The lifting-surface programs have been used successfully in practice for the design and global performance prediction of the marine propellers. To predict the pressures on the blade for the strength analysis, the constant panel method has been a good alternative. To meet the need for more accurate information on the pressure near the tip region and the trailing edge of the blade, the higher order panel method (HiPan, hereinafter) based on a B-spline is developed and now available. However, there is an increasing demand to get the highly reliable unsteady behavior of the pressure near the tip region by the HiPan. The ultimate goal of our efforts is to develop the fully unsteady higher order panel code for the propeller. In the present paper, we will show the numerical procedure applicable to unsteady problems of the three dimensional hydrofoil in a sinusoidal gust and heave motions.

• 한국정보통신학회논문지
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• 제19권6호
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• pp.1515-1524
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• 2015

최근 선박의 부식을 방지할 목적으로 전기적인 방식 장치를 이용하여 선체와 프로펠러의 부식을 방지하는 장치가 많이 이용되고 있는 추세이다. 그러나 전기적 방식 방법은 선체 내부의 전원장치에 의해 선체 주위의 해수로 전류를 방사하여 선체와 프로펠러가 부식이 되지 않는 상태로 인위적으로 만들어 주는 방법을 사용하는데, 해수에 방사되는 방식전류로 인하여 선체 외부에서 전자장 신호가 발생하게 된다. 본 논문에서는 선체 외부의 수중에서 발생하는 전자장 신호를 분석하고, 이에 대한 감소 대책에 대한 연구를 수행하는 것을 목표로 하였다. 기존의 축 접지 시스템에서는 축 전위가 100[mV] 이상 이며, 교류 전류 성분이 전체의 10% 이상을 차지하였으나, 본 논문에서는 방식전류내에서 교류전자장을 발생하는 교류 전류 성분과 축 전위가 각각 1% 와 2[mV]이내로 유지되게 하는 제어 시스템을 설계하고, 모의 실험을 통하여 그 성능을 입증하였다.

• 한국유체기계학회 논문집
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• 제3권2호
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• pp.31-35
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• 2000

In this research, the performance predictions of the submersible mixer were investigated. The variation of the performance characteristics by changing the impeller design parameters were discussed through the flow calculation results by using a commercial program, FLUENT. The performance of the submersible mixers is related to the velocity diffusion profiles downstream of the impeller and also the required input motor power to mix the fluid. In this study, the various design parameters such as the number of blade, the hub and tip diameters, the impeller blade profiles and revolution speed of the blades were taken for the fixed values. The blade sweep direction, the chord length distribution along with the radius of the blade and the inlet blade angle were changed to make different testing models. The flow calculation results show the effect of the changed design parameters on the performance of the submersible mixers and also give some helpful information for designing more efficient submersible mixers.