Distortion of the Compression Wave Propagating Through a Very Long Tunnel with Slab Tracks

Fukuda, Takashi; Ozawa, Satoru; Iida, Michihisa; Takasaki, Toru; Wakabayashi, Yusuke

doi:10.1299/kikaib.71.2248

Cited by 9 publications

(18 citation statements)

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“…Fukuda et al (5) proposed the 1D CFD technique based on following and reported that numerical results are consistent with field test data obtained for an actual Shinkansen.…”

Section: Governing Equationsmentioning

confidence: 56%

“…Therefore, many numerical studies have been reported (2), (5) - (9) . For example, Fukuda et al (5) proposed a 1D CFD technique considering effects of the wall friction and heat transfer, and reported that numerical results calculated using it agreed well with field test data for an actual Shinkansen tunnel. Furthermore, the higher the train speed is, the more important it is to suppress the steepening of the wavefront of the tunnel compression wave and the peak value of the micropressure wave because the higher the train speed is, the greater the nonlinear effects become.…”

Section: Introductionmentioning

confidence: 92%

“…In a longer tunnel, the peak value of the micro-pressure wave tends to become greater. In the case of a very long slab track tunnel, such as propagation distance of the compression wave is greater than 10 km, the compression wavefront tends to attenuate with propagation because of superiority of effects of the friction, large shafts, and many short side branches installed at regular intervals (5) . In addition, distortion of the compression wave also depends on the initial waveform at the tunnel entrance.…”

Section: Introductionmentioning

confidence: 99%

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A New Simple Equation Governing Distortion of Compression Wave Propagating Through Shinkansen Tunnel with Slab Tracks

Miyachi

Ozawa

Fukuda

et al. 2013

JFST

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A high-speed train entering a tunnel generates a compression wave that propagates through the tunnel toward its exit. When the compression wave reaches the tunnel exit, a pressure pulse causing environmental problems (the micro-pressure wave) is radiated from the exit portal. The micro-pressure wave magnitude is approximately proportional to the maximum pressure gradient of the tunnel compression wave arriving at the exit portal. In a long Shinkansen tunnel with concrete slab tracks, the compression wavefront steepens due to the nonlinear effect during its propagation because all surfaces of the tunnel wall are smooth. Therefore, it is necessary to investigate the compression wave distortion in a tunnel and to clarify the characteristics of the compression wave propagation for estimating and reducing the magnitude of the micro-pressure wave. In this paper, we introduce a new simple equation governing distortion of the tunnel compression wave propagating through a Shinkansen tunnel with concrete slab-tracks. We propose a new simple scheme for numerical calculations. A space evolution type equation with one variable is derived from the three conservation equations (mass, momentum, and energy including the wall friction and heat transfer terms) of the 1D CFD by assuming small disturbances excited by the compression wave. The numerical calculation scheme based on the simple equation reduces the computing time remarkably because its CFL condition is relaxed. The calculation results obtained using the proposed scheme agree well with those by a conventional scheme based on the 1D CFD. The accuracy of the simple equation is verified.

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“…Fukuda et al (5) proposed the 1D CFD technique based on following and reported that numerical results are consistent with field test data obtained for an actual Shinkansen.…”

Section: Governing Equationsmentioning

confidence: 56%

Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A New Simple Equation Governing Distortion of Compression Wave Propagating Through Shinkansen Tunnel with Slab Tracks

Miyachi

Ozawa

Fukuda

et al. 2013

JFST

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“…the maximum of its gradient increases) as it propagates through slabtrack tunnels. The larger the maximum of the gradient of the compression wave at the tunnel entrance portal is, by far the larger its increase becomes [3]. Consequently, decreasing this maximum pressure gradient at the tunnel entry portal is very effective for mitigating micro-pressure waves.…”

Section: Introductionmentioning

confidence: 99%

Countermeasure for Reducing Micro-pressure Wave Emitted from Railway Tunnel by Installing Hood at the Exit of Tunnel

Saito

Miyachi

Iida³

2013

QR of RTRI

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“…This non-linear effect of acoustic propagation causes the strength of the micro-pressure wave to become comparable to the sonic bang from a supersonic aircraft. Fukuda et al [2] found that the compression wave in a tunnel longer than the shock formation distance once develops a shock profile, and then reverts by friction to a waveform with reduced steepness causing less subjective effects on the environment. Integrated numerical simulations will be necessary to investigate the propagation of compression wave and the radiation of micropressure wave such that the progressive characteristics of compression wave are interconnected to the original waveform.…”

Section: Introductionmentioning

confidence: 99%

Analysis of tunnel compression wave generation and distortion by the lattice Boltzmann method

Akamatsu

Tsutahara

2010

WIT Transactions on Engineering Sciences

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The finite difference lattice Boltzmann method was applied to investigate the generation of the compression wave produced when a high-speed train enters a tunnel and the distortion of the wave front as it travels in the tunnel. The discrete Boltzmann equation for the 3D39Q thermal BGK model is solved in threedimensional space using a second-order Runge-Kutta scheme in time and a third order upwind finite difference scheme in space. The arbitrary LagrangianEulerian formulation is applied to model the interaction of the moving train nose and the tunnel portal. Numerical calculations are carried out for axisymmetric trains with various nose profiles entering a long circular cylindrical tunnel with straight and stepwise flared portals. The generation of the compression wave can be described in terms of flow parameters along the train nose and the interaction with the tunnel portal. The train speed and the train to tunnel area dependence of the predicted wave strength are found to be in good agreement with an analytic linear prediction. The distortion of the compression wave front that travels within an acoustically smooth tunnel is consistent with the time-domain computation of the one-dimensional Burgers equation. The non-linear steepening is confirmed to be dependent on the initial steepness of the wave front, which is determined by the interaction of the train nose and the tunnel portal. The tunnel entrance with flared portals is shown not only to decrease the initial steepness of the compression wave front but also to counteract the effect of non-linear steepening.

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Distortion of the Compression Wave Propagating Through a Very Long Tunnel with Slab Tracks

Cited by 9 publications

References 0 publications

A New Simple Equation Governing Distortion of Compression Wave Propagating Through Shinkansen Tunnel with Slab Tracks

A New Simple Equation Governing Distortion of Compression Wave Propagating Through Shinkansen Tunnel with Slab Tracks

Countermeasure for Reducing Micro-pressure Wave Emitted from Railway Tunnel by Installing Hood at the Exit of Tunnel

Analysis of tunnel compression wave generation and distortion by the lattice Boltzmann method

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