Attenuation and distortion of compression waves propagating in very long tube

Nakamura, Shuichi; Sasa, Daisuke; Aoki, Toshiyuki

doi:10.1007/s11630-011-0434-0

Cited by 6 publications

(3 citation statements)

References 4 publications

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“…The time wavelengths of the compression wave are almost 100 ms in the Shinkansen tunnels. The Reynolds number based on the compression wave passage time 20 is 105<Re~umax *Δt/ν<106, where umax * is the maximum air speed excited by the compression wave, and the transition Reynolds number 13,14,20 Ret of a boundary layer excited by the compression wave on the smooth pipe wall is Ret~106. Thus, Re is less than Re t in a boundary layer excited by the compression wave created by the train entering a tunnel.…”

Section: Discussionmentioning

confidence: 99%

“…Many studies have been undertaken to clarify the propagation characteristics of the compression wave in tunnels. 2,[5][6][7][8][9][10][11][12][13][14] For instance, Fukuda et al 11 measured the distortion of the compression wave in a 26-km-long slab track tunnel in Japan and developed a numerical method for its prediction. However, their results were only for the simple case of a compression wave with a single peak in the waveform of the pressure gradient since a hood was not installed at the tunnel entrance.…”

Section: Introductionmentioning

confidence: 99%

“…Many studies have been undertaken to clarify the propagation characteristics of the compression wave in tunnels. 2,5–14 For instance, Fukuda et al. 11 measured the distortion of the compression wave in a 26-km-long slab track tunnel in Japan and developed a numerical method for its prediction.…”

Section: Introductionmentioning

confidence: 99%

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Propagation characteristics of tunnel compression waves with multiple peaks in the waveform of the pressure gradient: Part 1: Field measurements and mathematical model

Miyachi

Saito

Fukuda

et al. 2015

Proceedings of the Institution of Mechanical Engineers, Part F:

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A high-speed train entering a tunnel generates a compression wave. When the compression wave reaches the exit portal of the tunnel, a micro-pressure wave radiates outward. The magnitude of the micro-pressure wave is approximately proportional to the pressure gradient of the compression wave arriving at the exit portal. As the micro-pressure wave can cause environmental problems, tunnel entrance hoods have been installed at many portals of long slab track tunnels on the Japanese high-speed railway, the Shinkansen to reduce the magnitude of the micro-pressure wave. In this study, field measurements were taken in a Shinkansen long slab track tunnel with a hood at its entrance. The compression wave distorts during its propagation through a long slab track tunnel. The dependence of the propagation characteristics on the initial compression waveform was clarified on the basis of field measurements on different trains and hood window configurations. It was shown that compression waves with a waveform of the pressure gradient that has shallow valleys tend to steepen more easily and that the optimum window pattern of the hood depends on the length of the tunnel. Furthermore, a mathematical model corresponding to the results of the field measurements was proposed to describe the distortion of the compression waves.

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