• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.1
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• pp.70-74
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• 2001

In this paper, we studied the maneuvering performances of a ship with flapped rudder. PMM tests were carried out for a ship model with horn type rudder or flapped rudder. The Abkowitz's model was used as a basic mathematical model to simulate the maneuvering motions. The maneuvering motions of a ship with flapped rudder were compared with those of a ship with horn-type rudder. As a result, it was found that the turning ability of a ship with flapped rudder was remarkably improved.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.892-895
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• 2017

As a component development of heavy duty industrial gas turbine combustor development program, pressure swirl simplex injector was designed and tested to figure out spray characteristics and performance. Injector flow rate as a function of pressure drop was measured and compared to the design target. Also spray shape was analyzed qualitatively and spray cone angle was measured from spray visualization image using shadowgraph. The flow test result showed that the injector was designed and manufactured correctly according to the design target and spray cone angle was measured from shadowgraph result. As a next step, PDA (Phase Doppler Anemometry) measurement is planned to figure out more specific spray performance and characterization.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.834-839
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• 2003

In the present study, the performance characteristics and the number of stall cells during rotating stall of a centrifugal air compressor were experimentally investigated. If the flow coefficient is lower than 0.150, the static pressure at impeller inlet is higher than that at inlet duct And reverse flow is observed under these flow coefficient region. Maximum adiabatic efficiency is obtained for the tested compressor around flow coefficient 0.128, and it is independent of compressor rotating speed. The number of stall cells and their rotational speeds are distinctive features of the rotating stall phenomenon. The present study is mainly concerned with the number of stall cells and their rotational speeds. The interpretation method of visualization is based on the pressure distribution in the circumference pressure fields while plotting the pressure and its harmonics variations in time in polar coordinates.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.1
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• pp.48-54
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• 2017

A minimum turning circle test of vehicles is operated by using Real-Time Kinematic(RTK) surveying method which enhances the precision of the Global Positioning System(GPS). A procedure of the conventional method to obtain results is to take post processing after the test. Therefore, it is difficult to ensure results in an instant. This paper introduces developed process and equipment that can immediately obtain results after the minimum turning test without post processing.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.12-13
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• 2018

For navigation safety, navigators have to be familiar with maneuverabilities. When a vessel encounters a danger of collisions and stranding, maneuverability is essential for the safety of ship. It is composed of turning, course change, speed change, etc. In the latter part, maneuverabilities and motion of Training Ship HANBADA are provided by full-scale measurement in the $10^{\circ}/10^{\circ}$ Zig-Zag Test, $20^{\circ}/20^{\circ}$ Zig-Zag Test and Turning Circle Test(Port and Starboard). It aims to provide information on maneuverabilities and motion of Training Ship HANBADA so that the navigators can take proper action to avoid.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.152-153
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• 2022

2020년 4월 부산신항에서 발생한 밀라노 브리지 사고는 초경하상태 선박의 조종성능 저하에 대한 큰 관심을 일으켰다. 본 연구는 흘수가 과도하게 작은 상태의 선박의 조종성능 저하에 대한 기초연구로 진행되었다. 이를 위하여 다양한 문헌 검토, 실증시험 및 시뮬레이션테스트를 진행하였고, 흘수가 지나치게 작은 선박은 만재 상태에 비하여 선회권의 크기가 커지므로 이에 대한 주의가 필요하다. 각 도선구에서는 입항하는 선박의 흘수가 지나치게 작을 경우 이를 제한하는 규제 도입에 대한 검토가 필요할 것으로 사료된다.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.11
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• pp.772-779
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• 2012

For improving performance of conical air diffuser generating fine bubble, both experimental and numerical simulation method were used. After adapting diffusers inner real scale bubble column, suitable for various diffuser submergence, the effect of diffuser submergence on oxygen transfer performance such as Oxygen Transfer Coefficient ($K_{L}a_{20}$) and Standard Oxygen Transfer Efficiency (SOTE) was investigated empirically. As flow patterns for various diffuser number and submergence were revealed throughout hydrodynamic simulation for 2-phase fluid flow of air-water, the cause of the change for oxygen transfer performance was cleared up. As results of experimental performance, $K_{L}a_{20}$ was increased slightly by 7% and SOTE was increased drastically by 39~72%, 5.6% per meter. As results of numerical analysis, air volume fraction, air and water velocity in bioreactor were increased with analogous flow tendency by increasing diffuser number. As diffuser submergence increased, air volume fraction, air and water velocity were decreased slightly. Because circulative co-flow is determinant factor for bubble diffusion and rising velocity, excessive circulation intensity can result to worsen oxygen transfer by shortening bubble retention time and amount.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.25 no.3
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• pp.133-133
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• 1989

The maneuverabilities of the M.S. Pusan 404 are studied, based on maneuvering indices and the data obtained from her Z test. The results obtained are summarized as follows: 1. The maneuvering indices K' and T' of the M.S Pusan 404 are 0.9359, 0.1955 at 10° Z test and 0.9781, 0.5802 at 20° Z test and 0.9108, 0.7090 at 30° Z test respectively. The above calculated values K', T' showed that her maneuverabilities are more effective when the rudder is used to small angle than to large angle. 2. As her maneuvering indices K' and T' at 10° Z test are smaller than the standard maneuvering indices of fishing boats, her turning ability was found to be lower but her obeying ability higher. 3. the running distance of a turn at her 10° Z test was about 8.7 times her own len호 and she was considered to have good maneuverabilities synthetically.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.25 no.3
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• pp.125-128
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• 1989

The maneuverabilities of the M.S. Pusan 404 are studied, based on maneuvering indices and the data obtained from her Z test. The results obtained are summarized as follows: 1. The maneuvering indices K' and T' of the M.S Pusan 404 are 0.9359, 0.1955 at 10$^{\circ}$ Z test and 0.9781, 0.5802 at 20$^{\circ}$ Z test and 0.9108, 0.7090 at 30$^{\circ}$ Z test respectively. The above calculated values K', T' showed that her maneuverabilities are more effective when the rudder is used to small angle than to large angle. 2. As her maneuvering indices K' and T' at 10$^{\circ}$ Z test are smaller than the standard maneuvering indices of fishing boats, her turning ability was found to be lower but her obeying ability higher. 3. the running distance of a turn at her 10$^{\circ}$ Z test was about 8.7 times her own len호 and she was considered to have good maneuverabilities synthetically.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.18 no.2
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• pp.77-80
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• 1982

The maneuverabilities of 240 GT class skipjack pole and liner were studied, based on the maneuvering indices and the data which were obtained from Z test of the experimental ship, the m.s. KWANACKSAN, the training ship of the National Fisheries University of Busan. The maneuvering indices K' of the experimental ship were 0.611(at 10$^{\circ}$Z test), 0.622(at 20$^{\circ}$Z test) and 0.556(at 30$^{\circ}$Z test). Her maneuvering indices T' were 1.094(at 10$^{\circ}$Z test), 1.695(at 20$^{\circ}$Z test) and 1.367(at 30$^{\circ}$Z test). The above calculated values K', T' showed that her turning ability at helm angle 20$^{\circ}$ and her obeying ability at helm angle 10$^{\circ}$ were most effective. As it appeared that the calculated K'-values of the experimental ship were smaller than the standard K'-values of different kinds of ships and her overshoot angles at her Z test were greater than those of them, her turning ability was found to be lower. When the experimental ship took a turn at her 10$^{\circ}$Z test, running distance was about 8.3 times her own length and didn't exceed the standard maneuvering distance, 5 to 11 times ship's own length, therefore she was considered to have good maneuverabilities synthetically.