• Proceedings of the KSME Conference
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• 2001.06e
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• pp.367-372
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• 2001

The paper presents an improved way of aerodynamic quality in Korean Very High Speed Railway, The pantograph model being under development dissatisfies the required grade of aerodynamic lift force. So the present work proposes modified configurations of panheads to maintain consistent aerodynamic characteristics. Analysis has been performed using commercial CFD program. Simulation based analysis has been conducted with two different models. One is to attach the thin plate on the crossbar and the other is the use of trapezoidal cross section in contact strip. Various length of thin plate is simulated for flow velocity and acceptable value of plate length is selected which satisfy the necessary average lift force. Aerodynamic variation on the panheads strip is studied.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.10a
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• pp.308-308
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• 2010

본 논문에서는 판토그라프의 공력소음 발생 특성을 규명하기 위하여 단순 모델을 이용하여 그 특성을 분석하였다. 단순 모델은 실제 팬헤드의 사이즈를 고려하여 선정하였고, 이를 통해 음압 해석 알고리즘을 구축하고 소음 발생 메커니즘을 분석하였다. 단순 모델을 선정하여 이를 Lattice Boltzmann Method 를 기반으로 한 전산 유체 해석을 통한 결과를 이용하여 음압 레벨과 음압의 방사형태를 계산하고, 풍동 실험을 통해 이를 검증한다. 풍동 실험에서는 단순 모델을 제작하여 100 km/h 의 속도 환경에서 항력, 양력과 소음을 측정하였다. 단면의 형상에 따른 변화 추이를 검토하였으며 해석결과를 단일 수치로도 정량화하여 제시한다. 최종적으로 정립된 알고리즘을 기반으로 팬헤드의 3 차원 모델을 시뮬레이션 한 결과를 제시한다.

• Proceeding of EDISON Challenge
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• 2014.03a
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• pp.579-584
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• 2014

고속 열차의 속도가 점점 빨라짐에 따라 고속 열차 주행 시 발생하는 여러 공력적인 문제가 대두되고 있다. 그 중 고속 열차와 전력선을 이어주는 판토그래프에서의 소음 발생과 압상력 불안정 문제가 중요시 되어왔고 이에 대한 여러 선행연구가 진행되고 있다. 지금까지의 선행 연구는 원형, 사각형, 에어포일과 같이 기본적인 형상을 이용한 판토그래프 팬헤드의 최적 단면 형상을 찾는 데에 초점을 맞추고 있다. 본 연구는 이러한 주류의 접근 방식에서 벗어나 팬헤드에 구멍을 추가하여 그 효과를 보는 다양한 시도를 해보았고 구멍이 소음 발생과 압상력 불안정에 미치는 영향에 대하여 연구하였다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.2
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• pp.83-91
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• 2003

Pantograph design Process must be considered in terms of stability of aerodynamics and reduction of aeroacoustics. Furthermore pantograph needs to be insensible to severe circumstance condition like typhoon, tunnel, a change of season. In this paper, robust design of panhead sections is conducted based on the Taguchi's design of experiment method. In the aeroacoustic noise analysis, an acoustic analogy using the Ffowcs Williams and Hawkings(FW-H) equation is used to calculate the flow induced sound pressure level in aeroacoustics. From the near-field CFD analysis data, the far-field noise is predicted at the positions of 25 m away from Pantograph. Based on aerodynamic(CFD) and aeroacoustic(FW-H) analysis data, the optimal sizing and Positioning of panhead elements are determined using robust design optimization method. Design parameters such as thickness, length and radius are controllable factors, while outdoor air temperature and atmospheric pressure are considered as uncontrollable factors in the context of Taguchi's approach. A number of CFD simulation and aeroacoustic analysis are performed based on orthogonal arrays. In this paper, two-step optimization method is used as a parameter design procedure. It is executed using signal to noise(S/N) ratio and analysis of means(ANOM) method. So Thus, an optimal level of design parameters Is extracted to minimize the disconnection ration between contact strips and catenary system, and reduce the far-field aeroacoustic noise.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1235-1241
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• 2001

Pantograph design process must be considered in terms of stability of aerodynamics and reduction of aeroacoustics. Furthermore Pantograph needs to be insensible to severe circumstance condition like typhoon, tunnel, a change of season. In this paper, robust design of panhead sections is conducted based on the Taguchi's design of experiment method. In the aeroacoustic noise analysis, an acoustic analogy using the Ffowcs Williams and Hawkings (FW-H) equation is used to calculate the flow induced sound pressure level. From the near-field CFD analysis data, the far-field noise is predicted at the positions of 25m away from panhead contact strips. Based on aerodynamic (CFD) and aeroacoustic (FW-H) analysis data, the optimal sizing and positioning ofpanhead elements are determined using robust design optimization method. Design parameters such as thickness, length and radius are controllable factors, while outdoor air temperature and atmospheric pressure are considered as uncontrollable factors in the context of Taguchi's approach. A number of CFD simulation and aeroacoustic analysis are performed based on orthogonal arrays. Using a parameter design procedure associated with signal-to-noise (SIN) ratio and sensitivity analysis, an optimal level of design parameters are extracted to minimize the disconnection ratio between contact strips and catenary system, and reduce the far-field aeroacoustic noise.