@Article{fdmp.2020.06525,
AUTHOR = {Yundong Han, Dawei Chen, Shaoqing Liu, Gang Xu},
TITLE = {An Investigation into the Effects of the Reynolds Number on High-Speed Trains Using a Low Temperature Wind Tunnel Test Facility},
JOURNAL = {Fluid Dynamics \& Materials Processing},
VOLUME = {16},
YEAR = {2020},
NUMBER = {1},
PAGES = {1--19},
URL = {http://www.techscience.com/fdmp/v16n1/38329},
ISSN = {1555-2578},
ABSTRACT = {A series of tests have been conducted using a Cryogenic Wind Tunnel to study
the effect of Reynolds number (Re) on the aerodynamic force and surface pressure
experienced by a high speed train. The test Reynolds number has been varied from 1
million to 10 million, which is the highest Reynolds number a wind tunnel has ever
achieved for a train test. According to our results, the drag coefficient of the leading car
decreases with higher Reynolds number for yaw angles up to 30º. The drag force
coefficient drops about 0.06 when Re is raised from 1 million to 10 million. The side force
is caused by the high pressure at the windward side and the low pressure generated by the
vortex at the lee side. Both pressure distributions are not appreciably affected by Reynolds
number changes at yaw angles up to 30º. The lift force coefficient increases with higher Re,
though the change is small. At a yaw angle of zero the down force coefficient is reduced by
a scale factor of about 0.03 when the Reynolds number is raised over the considered range.
At higher yaw angles the lift force coefficient is reduced about 0.1. Similar to the side force
coefficient, the rolling moment coefficient does not change much with Re. The magnitude
of the pitching moment coefficient increases with higher Re. This indicates that the load on
the front bogie is higher at higher Reynolds numbers. The yawing moment coefficient
increases with Re. This effect is more evident at higher yaw angles. The yawing moment
coefficient increases by about 6% when Re is raised from 1 million to 10 million. The
influence of Re on the rolling moment coefficient around the leeward rail is relatively
smaller. It increases by about 2% over the considered range of Re.},
DOI = {10.32604/fdmp.2020.06525}
}