• Proceedings of the KSR Conference
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• 2011.10a
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• pp.150-157
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• 2011

Nowadays, high speed train has settled down as a fast and convenient environment-friendly transportation and it's need is gradually increasing. However increased train speed leads to increased aerodynamic noise, which causes critically affects comfortability of passengers. Especially, the pantograph of high speed train is protruded out of train body, which is the main factor for increased aerodynamic noise. Since aerodynamic noise caused pantograph should be measured in high speed, it is difficult to measure it and to analysis aerodynamic noise characteristics due to the various types of pantograph. In this research, aerodynamic noise of pantograph is predicted by CFD (Computational Fluid Dynamic) and FW-H (Ffowcs Williams-Hawkings) equation. Also, Wind tunnel test results and numerical simulation results were compared. As a result, Simulation results predicting sound pressure level is very similar with wind tunnel test result. This research will draw major factor in aerodynamic noise of pantograph and will be utilized for predict sound pressure level of pantograph.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1449-1452
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• 2006

When fluid at high speed flows over an open cavity, large acoustic pressure fields inside the cavity are produced by fluid/structure interactions at the downstream end of the cavity. The inter-coach spacing is one of the most important sources of the aero-acoustic noise of a high-speed train. This noise can usually be heard as low frequency structure-borne noise inside the train. In this study experiments were performed in order to investigate the effects of mud-flap length on the aeroacoustic noise generation inside high-speed trains. Results of the measurement confirmed that the characteristics of the noise generated from the inter-coach spacing are strongly dependent on the size of the gap. Also investigated are the characteristics of the turbulent flow after the inter-coach spacing and consequent generation of the aeroacoustic noise inside the cabin.

• Journal of the Korean Society for Railway
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• v.10 no.1 s.38
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• pp.22-28
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• 2007

During the passage of the train, the railway bridge undergoes vibration and noise. The noise of railway bridge can be occurred from various sources. The wheel-rail contact, noise from machinery parts, structural-borne noise, pantagraph noise and aerodynamic noise of the train work in combination. Running train is one of the most important factors for railway bridge vibration. The repeated forces with equidistant axles cause the magnification of dynamic responses which relates with maintenance of the track structure and structure-borne noises. The noise problem is one of the most important issues in services of light rail transit system which usually passes through towns. In the present study, The vibration and noise of the LRT bridge will be investigated with utilizing dynamics responses from moving train as input data for noise analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.145-149
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• 2001

In this study, an acoustical characteristics of sound proof panel for high speed train was performed. A sound absorption coefficient and transmission loss of sound proof panels for high speed train were tested in reverberation chambers and compared those of ordinary sound proof panel. The effect of noise barrier was simulated by using ray noise program with measured sound absorption coefficient for high speed train case and for ordinary case.

• Journal of the Korean Society for Railway
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• v.10 no.4
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• pp.405-408
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• 2007

In this paper, we describe the analysis of interior noise for tilting train that is being developed in Korea. Tilting train is made of composite material to reduce the car body's weight and attached a self-steering system on bogie to improve curving performance. However, the acoustic performance (Transmission Loss) of such material is worse than the materials of conventional train, such as aluminum, steel and so on. Therefore, we measure the transmission loss of side wall/floor of tiling train and predict the interior noise for tilting train using its measuring results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.10
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• pp.1014-1023
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• 2008

Subway electric trains need to be faster for accommodation of long distance passengers. The faster run of the existing trains results in deterioration of ride quality due to noise and vibration. To reduce the noise and vibration of the electric train, a running test of the electric train was performed and an ADAMS/Rail model was set up to verify the running test results. The experimental results show that the sources of the cabin noise and vibration basically comes from the irregularity of the railroad track and the deterioration of the connection part between cabin and bogie. Consequently for mitigation of noise and vibration of the electric train, the redesign of the center pivot with softer stiffness and the minimization of rail irregularity are necessary. the frequent maintenance of the train will lead to better comport.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.88-91
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• 2007

Turnout system is a mechanical installation enabling trains to be guided from one track to another which is consists of point blades, common crossing and guard rail etc. These structural feature causes vibration, noise and damages while railroad car wheel is passes by. A tilting train is a train with a tilting mechanism that enables increased speed on regular railroad tracks. The aim of this paper is to study a characteristics of the shock-vibration and noise of tilting and existing train passes by turnout systems. To analyze and assesment, noise and vibration measurement was carried out at the Naesu-station of Chungbuk-line which equipped with cast manganese crossing and built-up crossing and Illo-station of Honam-line which equipped with cast manganese crossing.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.447-453
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• 2012

Nowadays, high speed train has settled down as a fast and convenient environment-friendly transportation and it's need is gradually increasing. However increased train speed leads to increased aerodynamic noise, which causes critically affects comfortability of passengers. Especially, the pantograph of high speed train is protruded out of train body, which is the main factor for increased aerodynamic noise. In this research, to reduce aerodynamic noise pantograph, panhead's shape changed to aerodynamical shape. aerodynamic noise of pantograph is predicted by CFD (Computational Fluid Dynamic) and FW-H (Ffowcs Williams-Hawkings) equation. Also, the sound pressure level of aerodynamic noise of base and modified models are predicted. And the reduction effects of the sound pressure level is analyzed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.85-86
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• 2006

It presented the approach method for the station braking noise present condition and a braking noise reduction plan escape of the KTX train. The research which it sees the technical ground it will be able to accomplish the station braking noise reduction of the KTX vehicle with base the questing matter where the escape one thing is big there is a possibility of doing.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.3
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• pp.335-344
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• 2008

In recent years, public complaints against railroad noise by KTX and Ordinary train have been rising. Regulation of railways noise uses same standard without distinguishing the type of railroad cars. According to the type of railroad cars, the frequency characteristics of emitting noise is different. Therefore it is requested to know how the public response vary to each types of railroad cars. The noise annoyance from three types of trains(KTX, electric train, diesel train) was analyzed by jury evaluation test for assessing the effect of frequency characteristics. The numerical results by a semantic differential method showed that annoyance response to three type of trains depended on the frequency characteristics. As a result, this study proposed that the KTX could have a bonus level of maximum 2.9 dB(A) compared to ordinary train.