Aerodynamic Noise Reduction of a Pantograph by Shape-Smoothing of Panhead and Its Support and by the Surface Covering with Porous Material

Ikeda, Mitsuru; Mitsumoji, Takeshi; Sueki, Takeshi; Takaishi, Takehisa

doi:10.1007/978-4-431-53927-8_50

Cited by 13 publications

(13 citation statements)

References 4 publications

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“…The experiments were run at flow speeds up to 400 km/h. Similar experimental setups have been used by Sueki et al [43] and by Ikeda et al [44]. However, in many cases the size of the component to be tested is too big compared with the size of the nozzle.…”

Section: Full Scale Tests On Componentsmentioning

confidence: 92%

Recent developments in the prediction and control of aerodynamic noise from high-speed trains

Thompson

Iglesias

Liu

et al. 2015

International Journal of Rail Transportation

125

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At speeds above 300-350 km/h, the main source of noise from trains is the aerodynamic noise caused by the air flow over the train structure. The sound level increases with train speed at a rate of between 60 and 80 times the logarithm of the speed so that, as speeds increase further, the noise increases dramatically. The main aerodynamic noise is produced by the air flow passing over the pantograph, the train nose, the bogie region and cavities such as the pantograph recess and the inter-coach gap. Experimental and numerical methods for studying aerodynamic noise are reviewed including the use of microphone arrays, wind tunnels, computational fluid dynamics and semi-empirical methods. Potential mitigation measures that can control aerodynamic noise are also reviewed.

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Section: Full Scale Tests On Componentsmentioning

confidence: 92%

Recent developments in the prediction and control of aerodynamic noise from high-speed trains

Thompson

Iglesias

Liu

et al. 2015

International Journal of Rail Transportation

125

View full text Add to dashboard Cite

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“…In order to improve prediction accuracy and optimization efficiency, taking samples with a compression ratio of 50%, for example, the relationship between sound absorption coefficient α and thickness d could be obtained by the Johnson-Allard model [10,[14][15][16], as shown in Equation (1), and parameters in Equation (1) could be obtained by the equations in Equation (2). Here, Z c is the characteristic impedance of the compressed porous Ni-Fe sample; k is the number of the wave in the compressed porous Ni-Fe sample; d is the thickness of the compressed porous Ni-Fe sample; φ is the porosity of the compressed porous Ni-Fe sample; Z 0 is the characteristic impedance of the air, 415.1 Pa · s · m −1 ; ρ(ω) is the effective density; K(ω) is the effective bulk modulus; ω is the angular frequency; f is the frequency of the acoustic wave; ρ 0 is the density of the air, 1.21 kg · m −3 ; c 0 is sound speed in air, 343 m · s −1 ; σ is the static flow resistivity of the compressed porous Ni-Fe, 1.02 × 10 4 Pa · s · m −2 ; γ is the specific heat ratio of the air, 1.40; P 0 is the static pressure of the air, 1.013 × 10 5 Pa; N u is the Nusselt number, 4.36; and Pr is the Prandtl number, 0.71 [10,[14][15][16].…”

Section: Influences Of Compression Ratios With Same Thicknessmentioning

confidence: 99%

“…Applications of porous metal in pollution control of urban noise make it a focus of research in the field of acoustics, because noise pollution greatly damages physical and mental health of humans and it can generate some diseases [1,2]. Relative to other porous materials, porous nickel-iron (Ni-Fe) alloy has the advantages of a high sound absorption coefficient, fine machinability, excellent thermal conductivity, good breathability, and outstanding fire resistance, which makes it a promising material for noise reduction [3,4].…”

Section: Introductionmentioning

confidence: 99%

Influences of Compression Ratios on Sound Absorption Performance of Porous Nickel–Iron Alloy

Bai

Shen

Zhang

et al. 2018

Metals

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Abstract:The improvement of sound absorption performance of porous metal is a focus of research in the field of noise reduction. Influences of compression ratios on sound absorption performance of a porous nickel-iron (Ni-Fe) alloy were investigated. The samples were compressed with ratios from 10% to 80% at an interval of 10%. Based on the standing wave method, sound absorption coefficients of compressed samples with different thicknesses were obtained. It could be found that with the same compression ratio, sound absorption performance was improved with the increase of thickness. Based on the modified Johnson-Allard model with a correction factor, the sound absorption coefficient of the porous Ni-Fe with a thickness of 20 mm for different compression ratios was derived, whose aim was to quantificationally analyze influences of the compression ratio. The results indicated that the sample with a compression ratio of 70% exhibited optimal sound absorption performance, and its average sound absorption coefficient reached 88.97% in a frequency range of 1000-6000 Hz. Meanwhile, the section morphologies of compressed samples were investigated by a scanning electron microscope, which studied the sound absorption performance by analyzing structures of the porous Ni-Fe samples with different compression ratios. The obtained achievements will promote the application of the porous Ni-Fe alloy in the field of acoustics.

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“…Sueki et al [15] proposed a new aerodynamic noise reduction method by using a porous material cover, which was experimentally proved effective for a cylinder or pantograph. Ikeda et al [16,17] put forward a few noise reduction techniques, including the relief of aerodynamic disturbances between articulated frame and shapeoptimized panhead.…”

Section: Introductionmentioning

confidence: 99%

On aerodynamic noises radiated by the pantograph system of high-speed trains

Zhang

2013

Acta Mech Sin

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Pantograph system of high-speed trains become significant source of aerodynamic noise when travelling speed exceeds 300 km/h. In this paper, a hybrid method of non-linear acoustic solver (NLAS) and Ffowcs WilliamsHawkings (FW-H) acoustic analogy is used to predict the aerodynamic noise of pantograph system in this speed range. When the simulation method is validated by a benchmark problem of flows around a cylinder of finite span, we calculate the near flow field and far acoustic field surrounding the pantograph system. And then, the frequency spectra and acoustic attenuation with distance are analyzed, showing that the pantograph system noise is a typical broadband one with most acoustic power restricted in the medium-high frequency range from 200 Hz to 5 kHz. The aerodynamic noise of pantograph systems radiates outwards in the form of spherical waves in the far field. Analysis of the overall sound pressure level (OASPL) at different speeds exhibits that the acoustic power grows approximately as the 4th power of train speed. The comparison of noise reduction effects for four types of pantograph covers demonstrates that only case 1 can lessen the total noise by about 3 dB as baffles on both sides can shield sound wave in the spanwise direction. The covers produce additional aerodynamic noise themselves in the other three cases and lead to the rise of OASPLs.

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Aerodynamic Noise Reduction of a Pantograph by Shape-Smoothing of Panhead and Its Support and by the Surface Covering with Porous Material

Cited by 13 publications

References 4 publications

Recent developments in the prediction and control of aerodynamic noise from high-speed trains

Recent developments in the prediction and control of aerodynamic noise from high-speed trains

Influences of Compression Ratios on Sound Absorption Performance of Porous Nickel–Iron Alloy

On aerodynamic noises radiated by the pantograph system of high-speed trains

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