The high-speed trains traveling at 400 km/h will generate severe alternating pressure and potential sonic boom when passing through tunnels. This paper proposed foam metal hoods (FMH) to mitigate the pressure waves induced by trains traversing tunnels. 1:20 scaled moving-model experiments were conducted to investigate the mitigation mechanisms of FMH on micro-pressure waves (MPW), residual pressure, and aerodynamic loads on the train and tunnel. The impact of FMH's installation position and length on MPW and residual pressure were discussed. The results indicate that the entrance FMH can weaken the expansion wave generated by the tail train entering the tunnel, thereby reducing the pressure amplitude on the train surface and tunnel wall. FMH can reduce the reflection intensity of pressure waves, effectively lowering the root mean square (RMS) of residual pressure. Installing FMH at both ends can reduce the RMS of residual pressure in the middle of the tunnel by 25%. The exit FMH enables the initial wavefront to gradually release pressure outward, thereby reducing MPW intensity. The radiation range of the MPW iso-surface is narrowed by energy consumption as the wavefront passes through the porous structures. The mitigation ratio of MPW intensifies as the length of the exit FMH increases. Using a 4-m-long exit FMH can decrease the MPW amplitude by 83.2% at 20 m from the FMH exit. The FMH facilitates a low-noise environment near tunnel portals, reducing the aerodynamic loads on the tunnel structures, and mitigating the train aerodynamic loads.

1.
P.
Chen
,
X.
Zhang
, and
D.
Gao
, “
Preference heterogeneity analysis on train choice behaviour of high-speed railway passengers: A case study in China
,”
Transp. Res. Part A Policy Pract.
188
,
104198
(
2024
).
2.
J.
Wang
,
T.
Wang
,
Y.
Wang
,
C.
Wen
,
L.
Zhang
, and
Z.
Sun
, “
Prediction and sensitivity analysis of the pressure wave peak value induced by the high-speed train in the long tunnel under a high geothermal environment
,”
Phys. Fluids
36
(
8
),
086106
(
2024
).
3.
Z.
Dai
,
T.
Li
,
W.
Zhang
, and
J.
Zhang
, “
Investigation on aerodynamic characteristics of high-speed trains with shields beneath bogies
,”
J. Wind Eng. Ind. Aerodyn.
246
,
105666
(
2024
).
4.
T.
Miyachi
,
Y.
Noguchi
, and
Y.
Yamauchi
, “
One-dimensional analysis of pressure variations induced by trains passing each other in a tunnel
,”
J. Fluid Mech.
988
,
1
28
(
2024
).
5.
K.
Wang
,
X.
Xiong
,
T.
Dong
, and
G.
Chen
, “
A two-dimensional revolving-axisymmetric model for assessing the wave effects inside the railway tunnel
,”
J. Wind Eng. Ind. Aerodyn.
248
,
105716
(
2024
).
6.
T.
Liu
,
Z.
Jiang
,
X.
Chen
,
J.
Zhang
, and
X.
Liang
, “
Wave effects in a realistic tunnel induced by the passage of high-speed trains
,”
Tunn. Undergr. Sp. Technol.
86
(
3
),
224
235
(
2019
).
7.
Y.
Liu
,
E.
Deng
,
W.
Yang
,
Y.
Ni
,
Z.
Zhou
, and
J.
Zhang
, “
Aerodynamic intensification effect and dynamic response of cracks on high-speed railway tunnel linings
,”
Tunn. Undergr. Sp. Technol.
140
(
6
),
105308
(
2023
).
8.
C.
Li
,
M.
Liu
,
R.
Chang
,
X.
Wang
,
W.
Liu
, and
H.
Zhang
, “
Air pressure and comfort study of the high-speed train passing through the subway station
,”
Sustain. Cities Soc.
81
,
103881
(
2022
).
9.
Y.
Peng
,
C.
Fan
,
L.
Hu
,
S.
Peng
,
P.
Xie
,
F.
Wu
, and
S.
Yi
, “
Tunnel driving occupational environment and hearing loss in train drivers in China
,”
Occup. Environ. Med.
76
(
2
),
97
104
(
2019
).
10.
B.
Auvity
and
M.
Bellenoue
, “
Effects of an opening on pressure wave propagation in a tube
,”
J. Fluid Mech.
538
,
269
289
(
2005
).
11.
X.
Xiang
,
L.
Xue
,
B.
Wang
, and
W.
Zou
, “
Mechanism and capability of ventilation openings for alleviating micro-pressure waves emitted from high-speed railway tunnels
,”
Build. Environ.
132
(
1
),
245
254
(
2018
).
12.
D. H.
Kim
,
S. Y.
Cheol
,
R. S.
Iyer
, and
H. D.
Kim
, “
A newly designed entrance hood to reduce the micro pressure wave emitted from the exit of high-speed railway tunnel
,”
Tunn. Undergr. Sp. Technol.
108
,
103728
(
2021
).
13.
S.
Saito
, “
Alleviation of micro-pressure waves radiated from tunnel hoods
,”
Tunn. Undergr. Sp. Technol.
147
,
105703
(
2024
).
14.
A. E.
Vardy
and
J. M. B.
Brown
, “
Influence of ballast on wave steepening in tunnels
,”
J. Sound Vib.
238
(
4
),
595
615
(
2000
).
15.
J. A.
Tebbutt
,
M.
Vahdati
,
D.
Carolan
, and
J. P.
Dear
, “
Numerical investigation on an array of Helmholtz resonators for the reduction of micro-pressure waves in modern and future high-speed rail tunnel systems
,”
J. Sound Vib.
400
,
606
625
(
2017
).
16.
T.
Wang
,
Y.
Zhu
,
X.
Tian
,
F.
Shi
,
L.
Zhang
, and
Y.
Lu
, “
Design method of the variable cross-section tunnel focused on improving passenger pressure comfort of trains intersecting in the tunnel
,”
Build. Environ.
221
,
109336
(
2022
).
17.
Z.
Chen
,
Z.
Guo
,
Y.
Ni
,
T.
Liu
, and
J.
Zhang
, “
A suction method to mitigate pressure waves induced by high-speed maglev trains passing through tunnels
,”
Sustain. Cities Soc.
96
(
5
),
104682
(
2023
).
18.
G.
Li
,
X.
Ye
,
E.
Deng
,
W.
Yang
,
Y.
Ni
,
H.
He
, and
W.
Ao
, “
Aerodynamic mechanism of a combined buffer hood for mitigating micro-pressure waves at the 400 km/h high-speed railway tunnel portal
,”
Phys. Fluids
35
,
126106
(
2023
).
19.
T.
Miyachi
and
T.
Fukuda
, “
Model experiments on area optimization of multiple openings of tunnel hoods to reduce micro-pressure waves
,”
Tunn. Undergr. Sp. Technol.
115
(
8
),
103996
(
2021
).
20.
J.
Zhang
,
Y.
Wang
,
S.
Han
,
F.
Wang
, and
G.
Gao
, “
A novel arch lattice-shell of enlarged cross-section hoods for micro-pressure wave mitigation at exit of maglev tunnels
,”
Tunn. Undergr. Sp. Technol.
132
,
104859
(
2023
).
21.
W.
Li
,
Y.
Gu
,
W.
Zhao
,
Y.
Deng
, and
X.
Fan
, “
Aerodynamic study of high-speed railway tunnels with variable cross section utilizing equivalent excavation volume
,”
Phys. Fluids
36
(
7
),
076120
(
2024
).
22.
Y.
Lu
,
T.
Wang
,
F.
Shi
,
L.
Zhang
, and
Y.
Wang
, “
A prompt design method of railway tunnel hoods for micro-pressure wave mitigation using CFD-based POD reconstruction
,”
Build. Environ.
250
,
111166
(
2024
).
23.
K.
Ootsuta
,
K.
Matsuoka
,
A.
Sasoh
, and
K.
Takayama
, “
Application of sound-absorbent plastic to weak-shock-wave attenuators
,”
Rev. Sci. Instrum.
69
(
4
),
1724
1729
(
1998
).
24.
B. D.
Wood
,
X.
He
, and
S. V.
Apte
, “
Modeling turbulent flows in porous media
,”
Annu. Rev. Fluid Mech.
52
,
171
203
(
2020
).
25.
V. V.
Calmidi
and
R. L.
Mahajan
, “
Forced convection in high porosity metal foams
,”
J. Heat Transf.
122
(
3
),
557
565
(
2000
).
26.
V.
Saxena
,
A.
Sharma
,
R.
Kothari
,
S. K.
Sahu
, and
S. I.
Kundalwal
, “
Analysis of Li-ion battery under high discharge rate embedded with metal foam phase change composite: A numerical study
,”
J. Energy Storage
84
,
110752
(
2024
).
27.
K.
Wang
,
G.
Chen
,
C.
Wen
,
X.
Xiong
,
X.
Liang
, and
L.
Zhang
, “
Mitigation mechanism of porous media hood for the sonic boom emitted from maglev tunnel portals
,”
Phys. Fluids
36
(
10
),
106134
(
2024
).
28.
P.
Zhao
,
Z.
Zhao
, and
C.
Yang
, “
Investigation of the orifice flow of over-the-rotor liner and its interaction with the rotor flow field
,”
Phys. Fluids
35
(
10
),
107144
(
2023
).
29.
D.
Sun
,
J.
Li
,
R.
Xu
,
X.
Dong
,
D.
Zhao
, and
X.
Sun
, “
Effects of the foam metal casing treatment on aerodynamic stability and aerocoustic noise in an axial flow compressor
,”
Aerosp. Sci. Technol.
115
,
106793
(
2021
).
30.
H.
Liu
,
J.
Wei
, and
Z.
Qu
, “
Prediction of aerodynamic noise reduction by using open-cell metal foam
,”
J. Sound Vib.
331
(
7
),
1483
1497
(
2012
).
31.
L.
Zhang
,
M.
Yang
,
X.
Liang
, and
J.
Zhang
, “
Oblique tunnel portal effects on train and tunnel aerodynamics based on moving model tests
,”
J. Wind Eng. Ind. Aerodyn.
167
(
8
),
128
139
(
2017
).
32.
C. E.
Standard
, “
Railway applications – Aerodynamics – Part 4: Requirements and test procedures for aerodynamics on open track
,” TSI/EN 14067-4,
2013
.
33.
J.
Niu
,
D.
Zhou
,
X.
Liang
,
S.
Liu
, and
T.
Liu
, “
Numerical simulation of the Reynolds number effect on the aerodynamic pressure in tunnels
,”
J. Wind Eng. Ind. Aerodyn.
173
(
12
),
187
198
(
2018
).
34.
C. E.
Standard
, “
Railway applications – Aerodynamics – Part 5: Requirements and test procedures for aerodynamics in tunnels
,” TSI/EN 14067-5,
2010
.
35.
D.
Zhou
,
H. Q.
Tian
,
J.
Zhang
, and
M. Z.
Yang
, “
Pressure transients induced by a high-speed train passing through a station
,”
J. Wind Eng. Ind. Aerodyn.
135
,
1
9
(
2014
).
36.
H.
Huang
and
J.
Ayoub
, “
Applicability of the Forchheimer equation for non-Darcy flow in porous media
,”
SPE J.
13
(
1
),
112
122
(
2008
).
37.
W. P.
Breugem
,
B. J.
Boersma
, and
R. E.
Uittenbogaard
, “
The influence of wall permeability on turbulent channel flow
,”
J. Fluid Mech.
562
,
35
72
(
2006
).
38.
N.
Sugimoto
,
M.
Masuda
,
J.
Ohno
, and
D.
Motoi
, “
Experimental demonstration of generation and propagation of acoustic solitary waves in an air-filled tube
,”
Phys. Rev. Lett.
83
(
20
),
4053
4056
(
1999
).
39.
A. L.
Marchant
,
T. P.
Billam
,
T. P.
Wiles
,
M. M. H.
Yu
,
S. A.
Gardiner
, and
S. L.
Cornish
, “
Controlled formation and reflection of a bright solitary matter-wave
,”
Nat. Commun.
4
(
5
),
1865
(
2013
).
40.
N.
Sugimoto
,
M.
Masuda
,
K.
Yamashita
, and
H.
Horimoto
, “
Verification of acoustic solitary waves
,”
J. Fluid Mech.
504
,
271
299
(
2004
).
41.
F.
Liu
,
M.
Wei
,
H.
Yang
,
X.
Song
,
Y.
Lan
,
D.
Chen
, and
K.
Wang
, “
Characterizing a device for easy simulation of compression waves induced by trains passing through tunnels
,”
Phys. Fluids
36
,
116123
(
2024
).
42.
T.
Miyachi
, “
Acoustic model of micro-pressure wave emission from a high-speed train tunnel
,”
J. Sound Vib.
391
,
127
152
(
2017
).
43.
K.
Wang
,
X.
Xiong
,
C.
Wen
,
G.
Chen
,
X.
Liang
,
H.
Huang
, and
J.
Wang
, “
Formation and propagation characteristics of a weak shock wave in maglev tube
,”
Phys. Fluids
36
,
036120
(
2024
).
44.
H.
Wang
,
A. E.
Vardy
, and
D.
Pokrajac
, “
Perforated exit regions for the reduction of micro-pressure waves from tunnels
,”
J. Wind Eng. Ind. Aerodyn.
146
,
139
149
(
2015
).
45.
H.
Wang
,
A. E.
Vardy
, and
D.
Pokrajac
, “
Pressure radiation from a perforated duct exit region
,”
J. Sound Vib.
351
(
5
),
29
42
(
2015
).
46.
M. L.
Shur
,
P. R.
Spalart
,
M. K.
Strelets
, and
A. K.
Travin
, “
A hybrid RANS-LES approach with delayed-DES and wall-modelled LES capabilities
,”
Int. J. Heat Fluid Flow
29
(
6
),
1638
1649
(
2008
).
47.
G.
Zhang
,
T. H.
Kim
,
D. H.
Kim
, and
H. D.
Kim
, “
Prediction of micro-pressure waves generated at the exit of a model train tunnel
,”
J. Wind Eng. Ind. Aerodyn.
183
(
8
),
127
139
(
2018
).
You do not currently have access to this content.