Numerical Simulation and Experimental Investigation of the Side Loading on a High Speed Train

Advances in Mechanical Engineering

2014

Interior noise in high-speed trains creates passenger discomfort and fatigue. In particular, the noise generated around the gangway between carriages tends to be easily transmitted to the passenger spaces due to the large noise component in the low-frequency region. In addition, the noise from the between-cars space around the gangway exterior tends to increase significantly when the high-speed train is travelling inside a tunnel. Therefore, this study analyses the cause of the noise generated in the gangways and identifies an effective method for reducing it. First, the mechanism for noise generation around the gangways was determined by computational flow noise analysis using a simple two-dimensional cavity model. From this simulation, it was confirmed that noise is generated when air flow enters the cavity. To investigate the influence of noise reduction in the between-cars section, blocking the airflow indirectly by installing fairings or directly by using side barriers was proposed. These noise reduction methods were examined by flow noise analysis, and then applied to an actual high-speed train. The interior noise was measured, and the results show that the use of side barriers was effective in reducing interior noise by 10 dB or more. In particular, a high noise reduction effect was exhibited in the low-frequency region. Therefore, this study verifies that directly blocking the inflow into the between-cars section is an effective noise reduction method.

“…In equation (4), T ij is Lighthill's stress tensor, which is an aerodynamic noise source. The solution to Lighthill's equation using Green's function is as follows…”

Section: Lighthill's Theory and The Fw-h Equationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Noise reduction in high-speed train gangways using fairings and side barriers

Advances in Mechanical Engineering

2014

“…Considering this aspect, several researchers attempted to clarify the mechanism of noise generation by performing a flow analysis of the between-cars sections of high-speed trains. 13,14 However, suitable reduction measures have not been proposed yet.…”

Section: Introductionmentioning

confidence: 99%

Improving the noise reduction performance of gangway bellows by using multilayered structures

Proceedings of the Institution of Mechanical Engineers, Part F:

2021

Excessive interior noise in railway vehicles is a major cause of fatigue and discomfort for passengers. In particular, the between-cars sections of high-speed trains experience considerable interior noise due to the poor noise reduction performance of the bellows, which are primarily made of silicone rubber and thus have a lower density than that of other components, made of extruded aluminum. Therefore, the objective of this study was to improve the noise reduction performance of such bellows. First, the material properties of silicone rubber were analyzed. Based on the results, the noise transmission of a simple model was analyzed to determine approaches required to reduce the low-frequency interior noise of the between-cars sections. It was confirmed that the low-frequency noise could be reduced by incorporating a multilayered panel of silicone rubber. Therefore, multilayered structures were considered for incorporation in the interior space of the between-cars sections of an actual high-speed train. A curved driving simulation of the between-cars sections indicated that no interference occurs when applying the proposed approach. Furthermore, a comparative test regarding the noise reduction performance was conducted considering cases involving bellows with and without multiple layers. The results of the verification test demonstrated that the noise reduction performance when using the proposed approach was improved by 4 dB compared with that in the case involving the conventional bellows, and an improvement of 8 dB or more was observed for noise with a low-frequency of 100 Hz.

“…This study focuses on identifying the mechanism of noise generation using a flow analysis of the between-car sections of a railway vehicle. 16–18 Many studies have been conducted to reduce noise by blocking inflow to the between-car sections. However, studies suggesting specific noise reduction measures are insufficient.…”

Section: Introductionmentioning

confidence: 99%

Improvement of noise reduction performance in bellows using multilayer perforated panels

Advances in Mechanical Engineering

2021

When the speed of a railway vehicle increases, the level of noise inside the vehicle inevitably increases as well, which is a major cause of discomfort to passengers. The most effective method is to improve the overall noise reduction performance of a vehicle. In particular, the gangway of the railway vehicle is made of silicone rubber; therefore, its noise reduction performance is inferior to that of other components of the vehicle. Thus, it is essential to improve the interior noise performance of railway vehicles. This study aims to reduce the noise in the low-frequency region of a railway vehicle gangway. It examines the applicability of the multi-layered resonance type panel, which has not been previously applied to the bellows in railway vehicles. In particular, the transmission loss was improved by changing the structure without filling the bellows with sound-absorbing material. First, a theoretical review of the noise reduction performance of a perforated multilayer structure was performed. Based on this, the major design parameters of the perforated multilayer structure that are effective in reducing noise in the low-frequency region of the bellows were derived. Through this, it was confirmed that in the multilayered structure, the hole diameter of 1 mm was effective in increasing the transmission loss in the low-frequency region, and the transmission loss was improved at 1% of the porosity. In addition, through a simple two-dimensional analysis model, it was confirmed that the transmission loss of the porous panel was improved at low frequencies of 100 to 400 Hz. Based on this result, a gangway with perforated multilayer structures was developed and tested. Through this verification test, it was confirmed that the noise performance of 9.2 dB was an improvement in the low frequency range of 100 Hz.