• Journal of the Korean Society for Railway
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• v.13 no.4
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• pp.376-381
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• 2010

In this study, field measurements on KTX, Nuriro and TTX train have been conducted at Kyeongbu and Honam line to predict the wind gust under train at the speed-up of major conventional railway lines using Kiel-probe array and multi-channel pressure scanning system. The results show that the average wind velocity during train passage normalized by train speed is independent to train speed, thus the wind gust for a given train type at the speed-up condition could be predicted. The relationship between the shape of underbody and the characteristics of the underbody wind gust has been discussed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.10
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• pp.75-81
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• 2005

Jettison, grid and CTS test are widely used for the store and stage separation studies. This is an introductory paper on the experimental methodology and typical results of grid and CTS test used for the Korean 3-stage sounding rocket development. Thirteen separation trajectories were evaluated in the ONERA S2MA wind tunnel at Mach numbers of 2.0 and 2.8. The test result was applied as the basic database for the design of optimized separation device.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.207-207
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• 2004

고속철도의 개통이 가까워지면서 사회적 관심이 고조되고 있으며, 특히 안전과 환경의 문제가 주요한 관심사로 대두되고 있다. 특히 공기역학적 관점에서 볼 때 300km/h의 고속에서는 지금까지 국내에서 경험하지 못한 여러 가지 문제점들이 나타나리라 예상되고 있으며, 그 중에서도 승강장에 대기증인 승객 또는 보행자가 열차 통과 시에 느끼는 불쾌감과 위험에 대한 조사와 대책이 필요한 시점이다.(중략)

• Journal of the Korean Society for Railway
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• v.19 no.1
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• pp.11-19
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• 2016

The flows around a high speed train are very important because they could affect the aerodynamic characteristics such as drag and acoustic noise. Especially the boundary layer of flows could represent the characteristic of flows around the high speed train. Most previous studies have focused on the boundary layer region along the train length direction for the side of the train and underbody. The measurement and analysis of the boundary layer for the roof side is also very important because it could determine the flow inlet condition for the pantograph. In this study, the roof boundary layer was measured with a 1/20 scaled model of the next generation high speed train, and the results were compared with full-scaled computational fluid dynamics results to confirm their validity. As a result, it was confirmed that the flow inlet condition for the pantograph is about 85% of the train speed. Additionally, the characteristics of the boundary layer, which increases along the train direction, was also analyzed.

• Journal of the Korean Society for Railway
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• v.8 no.1
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• pp.6-14
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• 2005

The mechanism of ballast-flying phenomena by strong wind induced by high-speed trains has extensively been investigated by conducting wind tunnel test and field-measuring of wind velocity in the vicinity of the track. The ballast gathered from the Seoul-Busan high-speed railway track has been classified by mass and shape to find relationship between those properties and the characteristic of movement in high wind and 16-channel Kiel-probe array has been used to examine the detailed flow structure above the surface of the track. The probability of ballast-flying during the passage of the high-speed train has been assessed comparing the results from wind tunnel test and that from field-measuring. The results shows that when the G7 train runs well as the KTX train runs at 300km/h, about 25m/s wind gust is induced just above the tie and the probability far small ballast under 50g to fly is about 50％ when it is on the tie. If the G7 train runs at 350km/h, the wind gust just above the tie increases to 30m/s, therefore radical countermeasure seems to be needed.