Cross-wind flows around two simplified high-speed trains with different nose shapes are studied using large-eddy simulation (LES) with the standard Smagorinsky model. The Reynolds number is 3×105 based on the height of the train and the freestream velocity. The cross section and the length of the two train models are identical while one model has a nose length twice that of the other. The three-dimensional effects of the nose on the flow structures in the wake and on the aerodynamic quantities such as lift and side force coefficients, flow patterns, local pressure coefficient, and wake frequencies are investigated. The short-nose train simulation shows highly unsteady and three-dimensional flow around the nose yielding more vortex structures in the wake. These structures result in a surface flow that differs from that in the long-nose train flow. They also influence the dominating frequencies that arise due to the shear-layer instabilities. Prediction of vortex shedding, flow patterns in the train surface, and time-averaged pressure distribution obtained from the long-nose train simulation are in good agreement with the available experimental data.

1.
Baker
,
C. J.
, 2003, “
Some Complex Applications of the Wind Loading Chain
,”
J. Wind. Eng. Ind. Aerodyn.
0167-6105,
91
, pp.
1791
1811
.
2.
Baker
,
C. J.
,
Jones
,
J.
,
Lopez-Calleja
,
F.
, and
Munday
,
J.
, 2004, “
Measurements of the Cross Wind Forces on Trains
,”
J. Wind. Eng. Ind. Aerodyn.
0167-6105,
92
, pp.
547
563
.
3.
Chiu
,
T. W.
, 1995, “
Prediction of the Aerodynamic Loads on a Railway Train in a Cross-Wind at Large Yaw Angles Using an Integrated Two- and Three-Dimensional Source/Vortex Panel Method
,”
J. Wind. Eng. Ind. Aerodyn.
0167-6105,
57
, pp.
19
39
.
4.
Chiu
,
T. W.
, and
Squire
,
L. C.
, 1992, “
An Experimental Study of the Flow Over a Train in a Crosswind at Large Yaw Angles up to 90°
,”
J. Wind. Eng. Ind. Aerodyn.
0167-6105,
45
, pp.
47
74
.
5.
Copley
,
J. M.
, 1987, “
The Three-Dimensional Flow Around Railway Trains
,”
J. Wind. Eng. Ind. Aerodyn.
0167-6105,
26
, pp.
21
52
.
6.
Suzuki
,
M.
,
Tanemoto
,
K.
, and
Maeda
,
T.
, 2003, “
Aerodynamic Characteristics of Train/Vehicles Under Cross Winds
,”
J. Wind. Eng. Ind. Aerodyn.
0167-6105,
91
, pp.
209
218
.
7.
Hoppmann
,
U.
,
Koenig
,
S.
,
Tielkes
,
T.
, and
Matschke
,
G.
, 2002, “
A Short-Term Strong Wind Prediction Model for Railway Application: Design and Verification
,”
J. Wind. Eng. Ind. Aerodyn.
0167-6105,
90
, pp.
1127
1134
.
8.
Diedrichs
,
B.
, 2003, “
On Computational Fluid Dynamics Modelling of Crosswind Effects for High-Speed Rolling Stock
,”
IMechE Conf. Trans.
1356-1448,
217
(F), pp.
203
226
.
9.
Durst
,
F.
,
Khier
,
W.
, and
Breuer
,
M.
, 2000, “
Flow Structure Around Trains Under Side Wind Conditions: A Numerical Study
,”
Comput. Fluids
0045-7930,
29
, pp.
179
195
.
10.
Hemida
,
H.
,
Krajnović
,
S.
, and
Davidson
,
L.
, 2005, “
Large-Eddy Simulations of the Flow Around a Simplified High Speed Train Under the Influence of a Cross-Wind
,” AIAA Paper No. AIAA-2005-5354.
11.
Krajnović
,
S.
, and
Davidson
,
L.
, 2004, “
Large Eddy Simulation of the Flow Around an Ahmed Body
,” in
2004 ASME Heat Transfer/Fluids Engineering Summer Conference
,
Charlotte
,
NC
.
12.
Singh
,
S.
, and
Mittal
,
S.
, 2005, “
Flow Past a Cylinder: Shear Layer Instability and Drag Crisis
,”
Int. J. Numer. Methods Fluids
0271-2091,
47
, pp.
75
98
.
13.
Kravchenko
,
G.
, and
Moin
,
P.
, 2000, “
Numerical Studies of Flow Over a Circular Cylinder at Re=3900
,”
Phys. Fluids
1070-6631,
12
(
2
), pp.
403
417
.
14.
Mittal
,
R.
, and
Moin
,
P.
, 1997, “
Stability of Upwind-Biased Finite Difference Schemes for Large-Eddy Simulation of Turbulent Flows
,”
AIAA J.
0001-1452,
35
(
8
), pp.
1415
1417
.
15.
Constantinuescu
,
G. S.
, and
Squires
,
K. D.
, 2003, “
LES and DES Investigations of Turbulent Flow Over a Sphere at Re=10,000
,”
Flow, Turbul. Combust.
1386-6184,
70
, pp.
267
298
.
16.
Krajnović
,
S.
, and
Davidson
,
L.
, 2005, “
Flow Around a Simplified Car, Part 1: Large-Eddy Simulation
,”
ASME J. Fluids Eng.
0098-2202,
127
, pp.
907
918
.
17.
Krajnović
,
S.
, and
Davidson
,
L.
, 2005, “
Flow Around a Simplified Car, Part 2: Understanding the Flow
,”
ASME J. Fluids Eng.
0098-2202,
127
, pp.
919
928
.
18.
Krajnović
,
S.
, and
Davidson
,
L.
, 2003, “
Numerical Study of the Flow Around the Bus-Shaped Body
,”
ASME J. Fluids Eng.
0098-2202,
125
, pp.
500
509
.
19.
Nilsson
,
H.
, and
Davidson
,
L.
, 1992, “
CALC-PVM: A Parallel Multiblock SIMPLE Multiblock Solver for Turbulent Flow in Complex Domains
,” Department of Thermo and Fluid Dynamics, Chalmers University of Technology, Technical Report.
20.
Sujudi
,
D.
, and
Haimes
,
R.
, 1995, “
Identification of Swirling Flow in 3D Vector Fields
,” AIAA Paper No. AIAA 95-1715.
21.
Jeong
,
J.
, and
Hussain
,
F.
, 1995, “
On the Identification of a Vortex
,”
J. Fluid Mech.
0022-1120,
285
, pp.
69
94
.
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