Dynamic analysis of the effect of nose length on train aerodynamic performance
Journal article, 2019
The improved delayed detached eddy simulation (IDDES) was used to study the influence of the train’s nose
length on its aerodynamic performance. Both the time-averaged and instantaneous near-wake structures and the
associated distribution of slipstream velocity are compared for three nose lengths. As the nose length increases,
the mean and Std values of the drag and lift force are decreased. The shorter nose-length case results in a higher
slipstream velocity. In particular, at the TSI track-side position, the TSI value U_2δ
for the 5-m nose length case is 30% and 32% higher than the corresponding values for the 7.5-m and 10-m nose length cases, respectively. The
dynamical flow topology in the wake reveals that the flow structures of the 5-m nose length are different from
those of the other two cases in the tail streamline surface. As nose length increases, the longitudinal vortices are
weaker, and the angle and distance between the longitudinal vortices are smaller. The shear production from the P_xy
caused by the separation of the boundary layer at the lateral wall of the tail train is greater than that of the P_xz
caused by the separation of the boundary layer at the top and bottom of the tail train.
length on its aerodynamic performance. Both the time-averaged and instantaneous near-wake structures and the
associated distribution of slipstream velocity are compared for three nose lengths. As the nose length increases,
the mean and Std values of the drag and lift force are decreased. The shorter nose-length case results in a higher
slipstream velocity. In particular, at the TSI track-side position, the TSI value U_2δ
for the 5-m nose length case is 30% and 32% higher than the corresponding values for the 7.5-m and 10-m nose length cases, respectively. The
dynamical flow topology in the wake reveals that the flow structures of the 5-m nose length are different from
those of the other two cases in the tail streamline surface. As nose length increases, the longitudinal vortices are
weaker, and the angle and distance between the longitudinal vortices are smaller. The shear production from the P_xy
caused by the separation of the boundary layer at the lateral wall of the tail train is greater than that of the P_xz
caused by the separation of the boundary layer at the top and bottom of the tail train.
Author
Guang Chen
Central South University
National & Local Joint Engineering Research Center of Safety Technology for Rail Vehicle
Joint International Research Laboratory of Key Technology for Rail Traffic Safety
Xiao Bai Li
Central South University
Joint International Research Laboratory of Key Technology for Rail Traffic Safety
National & Local Joint Engineering Research Center of Safety Technology for Rail Vehicle
Zhen Liu
Central South University
Joint International Research Laboratory of Key Technology for Rail Traffic Safety
National & Local Joint Engineering Research Center of Safety Technology for Rail Vehicle
Dan Zhou
National & Local Joint Engineering Research Center of Safety Technology for Rail Vehicle
Central South University
Joint International Research Laboratory of Key Technology for Rail Traffic Safety
Zhe Wang
National & Local Joint Engineering Research Center of Safety Technology for Rail Vehicle
Central South University
Joint International Research Laboratory of Key Technology for Rail Traffic Safety
Xifeng Liang
National & Local Joint Engineering Research Center of Safety Technology for Rail Vehicle
Central South University
Joint International Research Laboratory of Key Technology for Rail Traffic Safety
Sinisa Krajnovic
Chalmers, Mechanics and Maritime Sciences (M2), Fluid Dynamics
Journal of Wind Engineering and Industrial Aerodynamics
0167-6105 (ISSN)
Vol. 184 198-208Areas of Advance
Transport
Subject Categories
Aerospace Engineering
Applied Mechanics
Fluid Mechanics and Acoustics
DOI
10.1016/j.jweia.2018.11.021