• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.69-70
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• 2016

선박과 유빙의 충돌로 발생하는 빙하중은 선체의 구조강도 문제뿐만 아니라 선박의 속력감소 및 조종운동에도 영향을 미친다. 이 연구에서는 DEM (Discrete Element Method) 기법을 이용하여 유빙을 항해하는 선박의 조종성능 평가를 위한 수치 시뮬레이션 프로그램을 개발한다. 여러가지 유빙 조건에서 선회성 시험 및 10/10 지그재그 시험을 시뮬레이션하여, 유빙의 상태가 선박의 조종성능에 미치는 영향을 파악한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.10a
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• pp.98-99
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• 2015

안전운항 관점에서 보았을 때, 거대형선박의 조종운동특성에 대하여 실무적으로 파악하는 것은 대단히 중요한 문제이다. 이 논문에서는 선형에 따른 거대형선박의 조종운동특성에 대해서 다루고 있다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.2
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• pp.308-318
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• 1988

The liquid disintegration and characteristics of atomization through the swirl nozzle is affected by injection pressure and injection time when the liquid is injected intermittently. These transient phenomena are investigated by electronic controlled-fuel injection nozzle. The effect of injection conditions on disintegration of liquid injected through nozzle is observed photographically by using delay circuit. Droplet size of the element of the sample is measured by the liquid immersion sampling technique. SMD of droplets is varied with time and is decreased as the injection pressure increases. As the injection pressure increases, the maximum diameter of droplet and diameter of droplet which has the maximum droplet number decrease. Spray angle is not affected on injection pressure and change of spray angle with time is associated with needle movement.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.251-256
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• 2003

The detailed flow characteristics inside a compression chamber due to the orbiting motion of a scroll is studied numerically. The orbiting motion of a scroll is modelled at 7 orbiting angles. At each orbit angle, the central compression chamber is modelled. All computations are carried by using an in-house code. It is based on the SIMPLE algorithm. Computation results show that the flow structure inside the compression chamber is dependent on the orbit angle. The pressure variation inside the compression chamber also shows great dependence on the orbit angle. The pressure variation shows local maxima when the orbiting motion of a scroll directs toward the center of the compression chamber.

• Journal of Navigation and Port Research
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• v.45 no.6
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• pp.284-297
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• 2021

A simple kinematic model for the prediction of ship manoeuvres based on trial data is proposed in this study. The model consists of first order differential equations in surge, sway, and yaw directions which simulate the time series of each velocity component. Actually instead of sea trial data, dynamic model simulations are conducted with randomly varied control inputs such as propeller revolution rates and rudder angles. Based on learning of control inputs and velocity outputs of dynamic model simulations in sufficient time, kinematic model coefficients are optimized so that the kinematic model can be approximately reproduce the velocity outputs of dynamic model simulations with arbitrary control inputs. The resultant kinematic model is verified with new dynamic simulation sets.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.11
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• pp.881-888
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• 2020

In this paper, research on estimation of states of a target of interest using Line Of Sight(LOS) angle measurement is performed. Target's position, velocity, and acceleration are chosen to be the states of interests. The LOS measurement is known to be highly non-linear, making target dynamic modeling hard to be implemented into a filter. To solve this issue, the Pseudomeasurement equation was applied to the LOS measurement equation. With the help of this equation, 3D variable turn target dynamic model is applied to the filter model. For better performance, Kinematic Constraint is also implemented into the filter model. As for the filter, Bias Compensation Pseudomeasurement Filter (BCPMF) is used which is known for its robustness to initial conditions. Moreover, Two-Stage Kalman Filter (TSKF) form was also implemented to benefit from the parallel computation. As a result, TBCPMF 3DVT-KC is proposed and simulated to assess performance.

• Journal of Korean Society of Transportation
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• v.20 no.2
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• pp.81-92
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• 2002

An automobile crash with a pedestrian generates a trajectory which is crucial to identify the cause of the crash. Previous researches have been carried out for pedestrian movement using simple explicit formulae. The formulae are derived from elementary physics. Therefore, they could not sufficiently include variables of a vehicle and a pedestrian. To overcome such a limitation, a simulation is utilized for the pedestrian behavior in crash environment. A dynamic software called MADYMO is utilized for the simulation. A simulation model is established. The automobile body and a dummy are modeled with rigid bodies, joints and springs. The simulation results are compared with those from explicit formulae. It is found that the explicit formulae did not fit to pedestrian conditions. Simulations are performed for various velocities of automobiles. Results are discussed for the usage of the simulation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.83-85
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• 2015

The Purpose of this paper was to carry out basic study on development of real-time submarine-hnadling simulator. The author adopt the Unmanned Undersea vehicle(UUV), which has taken the shape of manta[1]. They call here it Unmanned Undersea Vehicle(UUV). UUV is based on the same design concept as UUV called Manta Test Vehicle, which was originally built by the Naval Undersea Warfare Center, USA[1]. The present study deals with prediction of manoeuvring motion of UUV at general drift angles and large drift angles. The dynamic mathematical model with six degrees of freedom is revised and supplemented in order to describe accurately motion of UUV. The hydrodynamic derivatives related to motion are obtained from previous work[2].

• Journal of Biosystems Engineering
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• v.16 no.4
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• pp.346-354
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• 1991

Turning behavior of tractor-trailer system was studied to guide the tractor and trailer. Based upon kinematic relationship between the tractor and the trailer, a mathematical model was developed and analyzed by computer simulation. A field test was carried out to verify the mathematical model. Following conclusions were drawn from this study. 1. A mathematical model and a simulation program for turning behavior of tractor-trailer system were developed. 2. The results of the field tests showed that the RMS errors were less than 0.33m and the mathematical model based upon kinematic relationship can be used for mapping guidance system for tractor and trailer. 3. As the steering angle was increased, the turning radius was decreased. When the tractor travelled at the low speed, the travel speed of the tractor did not affect turning radius but did affect running time and stability for steering. 4. When the tractor travelled under the critical velocity, the towed trailer followed smoothly. When the the tractor travelled faster than the critical velocity, the towed trailer oscillated. The critical velocity was determined from the specification of the tractor and the trailer.

• Journal of ILASS-Korea
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• v.20 no.2
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• pp.70-75
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• 2015

Swirl flow in the gun type burner has an impact on the stabilization of the flame, improvement of the combustion efficiency. The swirl flow is created by the spinner which is inside the airtube that guide the combustion air. Gun type burner has generally the inner devices composed electronic spark plug, injection nozzle, combustion device adaptor, and spinner. These inner components change the air flow behavior passing through airtube. So, this study conducted the measurement using by hot-wire anemometer and analyzed effect of the swirl number of spinner on the exhaust air of gun type burner. Turbulence characteristics come up in this study was mean velocity, turbulence intensity, kinetic energy, shear stress and flattness factor of the air flow with the change of the distance of axial direction and tangential direction from the exit of the airtube.