• 한국철도학회논문집
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• 제8권5호
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• pp.454-459
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• 2005

In this study, the relationship between tie shape and underbody train gust of high-speed train is numerically investigated. To this end, complex train underbody/railroad model is replaced by simple plate/tie model. And it is tried to find a most important parameter for reduction of underbody train gust through the Taguchi method and orthogonal array. As a result, it is verified that the height of tie is most sensitive to the underbody train gust because of the cavity effect between ties. When the width and distance between ties are decreased, underbody train gust is also reduced. Consequently, the heighter is examined which can give the similar effect of higher tie without replacement of tie. The 5cm heighter can reduce underbody train gust about $73\%$, which value is only $7\%$ less than the higher tie.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.1241-1247
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• 2005

The ballast-flying, induced by strong underbody train gust, may damage train underbody, wheel and even cause the safety problems. For this reason, a heighter is being used to prevent the ballast-flying phenomenon through underbody now reduction. In this research, flow field around a heighter is numerically simulated. And the parametric study of various heighter shapes is performed to find out more effective heighter shape. Also the ballast-flying probabilities are calculated for various ballast types and train speeds.

• 한국철도학회논문집
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• 제13권4호
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• pp.376-381
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• 2010

본 연구에서는 주요 간선 철도 노선의 고속화 시 열차풍 예측을 위하여 KTX 열차, 누리로 열차 및 TTX 열차를 대상으로 호남선과 경부선에서 Kiel-probe를 이용한 열차풍 측정 프루브 어레이와 다채널 압력측정 시스템을 이용하여 열차풍 현장 측정 시험을 수행하였다. 시험 결과, 열차가 통과하는 동안의 열차하부 평균유속을 열차의 속도로 나눈 값은 열차 속도에 무관하고 차량의 종류에만 관계하기 때문에, 주어진 열차의 종류와 열차 속도에 대하여 열차 하부의 유속을 예측할 수 있는 것으로 나타났다. 또한 열차 하부 형상과 하부 열차풍특성의 관계에 대해서도 논하였다.

• 한국철도학회논문집
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• 제12권1호
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• pp.39-44
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• 2009

차륜이나 기타 궤도주변의 구조물에 동에 충돌하여 유험을 초래할 수 있는 자갈비산 현상은 고속으로 달리는 열차의 하부에 유도되는 돌풍에 의해 발생 가능하다. 자갈비산을 방진하기 위한 방법 하나로 선로상의 자갈표면 유속을 감소시키는 높임침목이 사용되고 있다. 본 연구에서는 다양한 높임침목의 형상에 대하여 전산해석을 이용하여 그 공력특성을 분석하였다. 높임침목의 높이가 높아질수록 유도되는 유속은 감소하였으며 폭의 변화는 큰 영향이 없음을 확인하였다. 또한 높임침목의 형상 변화에 따라 자갈궤도면에 유도되는 유속을 검토하여 유동방향에 대하여 뾰족하고 각진 높임침목 형상이 효과적임을 알 수 있었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.369-373
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• 2005

To investigate the mechanism of ballast-flying phenomena by strong wind induced by high-speed trains, wind velocity in the vicinity of the track has been measured using 16-channel Kiel-probe array and detailed flow structure near the surface of the track has been analyzed. The position at which the underflow fully develop has been examined in order to assess the driving force of the turbulent flow under train and the results yields that the turbulent flow owing to the cavity of the inter-car as well as the friction force at the underbody of the train is the main reason of the strong wind under high-speed train. The preceding wind tunnel test results has been introduced to assess the probability of ballast-flying during the passage of the high-speed train by comparing the results from field-measuring. The results shows that when the G7 train as well as the KTX train runs at 300km/h, about 25m/s wind gust is induced just above the tie and the probability for 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 more radical countermeasure seems to be needed.