Numerical analysis of dipole sound source around high speed trains

Takaishi, Takehisa; Sagawa, Akio; Nagakura, Kiyoshi; Maeda, Tsuyoshi

doi:10.1121/1.1480833

Cited by 12 publications

(5 citation statements)

References 8 publications

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“…47 Thus, for the exterior noise of high-speed train which operated at low Mach number, the quadrupole term can be ignored and the dominant sources are more typically dipole-type sources. 32,44 Experimental configuration…”

Section: Fw-h Acoustic Analogymentioning

confidence: 99%

“…SPL, L p , reports sound level under each specified frequency, which is defined as where p(t) is the RMS sound pressure in Pa; pref=20μ, Pa is the reference sound pressure. 32…”

Section: Aeroacoustic Fieldmentioning

confidence: 99%

“…Experimental methods including full-scale tests, 9,26,27 wind tunnel tests 9,[28][29][30] and computational simulations [31][32][33] are the main methods in the research of the aeroacoustic features of high-speed trains. Besides the high cost of full-scale tests mentioned above, it is not easy to distinguish sound sources accurately.…”

Section: Introductionmentioning

confidence: 99%

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Numerical simulation of the slipstream and aeroacoustic field around a high-speed train

Zhu

Hemida

Flynn

et al. 2016

Proceedings of the Institution of Mechanical Engineers, Part F:

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Section: Fw-h Acoustic Analogymentioning

confidence: 99%

“…SPL, L p , reports sound level under each specified frequency, which is defined as where p(t) is the RMS sound pressure in Pa; pref=20μ, Pa is the reference sound pressure. 32…”

Section: Aeroacoustic Fieldmentioning

confidence: 99%

See 1 more Smart Citation

Numerical simulation of the slipstream and aeroacoustic field around a high-speed train

Zhu

Hemida

Flynn

et al. 2016

Proceedings of the Institution of Mechanical Engineers, Part F:

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show abstract

“…T. Sassa combined BEM with finite element method to simulate the noise on the surface of the high-speed train and analyze noise characteristics [13]. Then, Takehisa adopted LES and Green function to simulate the distribution of dipole sources on the surface of the high-speed train and formed some knowledge of the distribution rule of dipole on the surface of the train [14,15]. Li used BEM to simulate and analyze interior sound field.…”

Section: Introductionmentioning

confidence: 99%

Multi-objective optimization for the aerodynamic noise of the high-speed train in the near and far field based on the improved NSGA-II algorithm

Yuan¹,

Li²

2017

J. vibroeng.

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With the increased running speed of trains, the aerodynamic noise of trains becomes increasingly obvious. Reducing aerodynamic noises has become one of keys to controlling the noise of high-speed trains. This paper conducted a numerical simulation on the aerodynamic noise of head of the high-speed train. Firstly, this paper established a mathematical-physical model for the three-dimensional turbulent flow field of a high-speed train, adopted standard-equation turbulent model and broadband noise source model to compute the aerodynamic noise sources of the high-speed train and applied three-dimensional transient large eddy simulation (LES) to compute the external unsteady flow field of the high-speed train after obtaining noise sources. Based on the unsteady flow field, then this paper applied FW-H equations to compute the far-field aerodynamic noise of the high-speed train. After obtaining the unsteady fluctuation pressure on the surface of the train, this paper computed the radiation characteristics of aerodynamic noises around the high-speed train based on the boundary element method (BEM). Researched results showed: The main aerodynamic noise sources of the high-speed train were at the nose tip of head train; fluid separation and recombination were main reasons for the aerodynamic noise of the highspeed train; vortexes in the position of head train were striped and horseshoe-shaped or hairpin vortexes were mainly in the area of tail train; in addition, vortexes were symmetrically distributed along the longitudinal symmetry plane of train; dipole noises were mainly distributed in the area of head train, whose main energy was decreased with the increased frequency; the quadrupole noise of aerodynamic noises of the high-speed train was mainly distributed in the wake flow area of tail train; when the high-speed train ran at the speed of 300 km/h, the maximum sound pressure level of far-field observation points was 76.8 dB; additionally, aerodynamic noises in the far field were mainly a broadband noise, whose main energy was within the frequency range of 1250 Hz to 3150 Hz. Finally, the improved NSGA-II algorithm was used to conduct a multi-objective optimization for the head shape. The aerodynamic drag of the high-speed train could be most reduced by 6.74 %, and the dipole aerodynamic noise source could be most reduced by 8.34 dB. The improved NSGA-II algorithm has an obvious effect on the multi-objective optimization of the head shape.

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“…Takehisa adopts large eddy simulation and green function method to study the distribution of dipole noise source on the surface of high-speed trains. The researched result has an important significance on recognizing the distribution of aerodynamic noises of high-speed trains [14,15]. Reference [16] adopts multi-channel data collection system to make noise experiments of high speed trains and studies noise level outside high-speed trains, main noise source and distribution characteristics at the speed of 350 km/h, which has an important significance on studying and controlling aerodynamic noises of high-speed trains.…”

Section: Introductionmentioning

confidence: 99%

Numerical computation of aerodynamic noises of the high speed train with considering pantographs

Wang¹,

Wang²,

Fu³

2016

J. vibroeng.

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With the improvement of the speed, aerodynamic noises of trains also become more obvious. Reducing the aerodynamic noise has become a key factor to control noises of the high speed train. This paper uses large eddy simulation and boundary element method to compute the flow field and aerodynamic noises of pantographs and trains. The result presents that there are obvious eddies at the head, push rod, and base. Two obvious separation eddies can be found around the guide rod of the head and the push rod of pantographs. The front part of the base has a layer of shear flow, which leads to a separation eddy in the back of the base while the flow moves backward. Noises of pantographs mainly concentrate around the head, base and pushrod. With the increase of the analyzed frequency, the strength of pantograph noise source is weaker and weaker. When the analyzed frequency is 500 Hz, the noise source of pantographs is mainly around joints of several structures. By comparing the computational and the experimental result of aerodynamic noises of pantographs, this result presents that they are consistent with each other in the change tendency and value within the whole analyzed frequency. This indicates that the computational model of aerodynamic noises of pantographs is effective. Pantographs have an obvious influence on the distribution of the flow field around high speed trains, especially at the end of high speed trains. High speed trains with pantographs only have an eddy at the end, but high speed trains without pantographs have two eddies at the end. When this paper conducts on numerical computation for high speed trains, pantographs should not be ignored. In the low frequency, radiation noises of high speed trains can be found mainly around pantographs and at the end of trains. At the longitudinal symmetric plane of high speed trains, the sound pressure level at the end of trains is the highest. The radiation noise around pantographs mainly concentrates around the pushrod, then base, and the last is the head.

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Numerical analysis of dipole sound source around high speed trains

Cited by 12 publications

References 8 publications

Numerical simulation of the slipstream and aeroacoustic field around a high-speed train

Numerical simulation of the slipstream and aeroacoustic field around a high-speed train

Multi-objective optimization for the aerodynamic noise of the high-speed train in the near and far field based on the improved NSGA-II algorithm

Numerical computation of aerodynamic noises of the high speed train with considering pantographs

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