When two trains going through a tunnel pass each other,the difference of the surrounding space between a train’s both sides rises,which induces abrupt aerodynamic force variations on the trains,resulting in the pheno...When two trains going through a tunnel pass each other,the difference of the surrounding space between a train’s both sides rises,which induces abrupt aerodynamic force variations on the trains,resulting in the phenomenon of sudden swaying.This study employs the unsteady Reynolds-averaged Navier-Stokes(URANS)method of numerical simulation to analyse the effects of two terrain conditions,that is,a tunnel with and without asymmetric mountain structures at its portals,on the aerodynamic characteristics of two trains during their intersections.The results indicate that during two trains’intersections at tunnel portals,the rear car suffers the highest risk of swaying.The presence of asymmetric mountain structures at tunnel portals reduces the risk of swaying the train adjacent to the mountains but increases the risk for trains farther away from the mountains.When trains intersect at the exit(for the train adjacent to the mountain)of the tunnel,the presence of mountain structures at the portal reduces the peak-to-peak lateral force values by 12.7%for the front car of the train adjacent to the mountain and increases by 16.5%for the rear car of the train away from the mountain.The impact of the mountain structures on the peak-to-peak values of a train’s lateral force is minimal when two trains intersect at the midpoint of the tunnel.Therefore,it is suggested to consider the placement of symmetrical buffer structures or the modification of existing mountain structures at appropriate locations near tunnel portals to mitigate the abrupt lateral force variations experienced by passing trains.展开更多
基金supported by the Science and Technology Research and Development Program of China Railway(Grant No.N2023J016)the Science and Technology Innovation Program of Hunan Province,China(Grant No.2022RC3040)+1 种基金the Natural Science Foundation of Hunan Province,China(Grant No.2022JJ30727)the Major Project of China Railway Design Corporation(Project No.2022A02480004).
文摘When two trains going through a tunnel pass each other,the difference of the surrounding space between a train’s both sides rises,which induces abrupt aerodynamic force variations on the trains,resulting in the phenomenon of sudden swaying.This study employs the unsteady Reynolds-averaged Navier-Stokes(URANS)method of numerical simulation to analyse the effects of two terrain conditions,that is,a tunnel with and without asymmetric mountain structures at its portals,on the aerodynamic characteristics of two trains during their intersections.The results indicate that during two trains’intersections at tunnel portals,the rear car suffers the highest risk of swaying.The presence of asymmetric mountain structures at tunnel portals reduces the risk of swaying the train adjacent to the mountains but increases the risk for trains farther away from the mountains.When trains intersect at the exit(for the train adjacent to the mountain)of the tunnel,the presence of mountain structures at the portal reduces the peak-to-peak lateral force values by 12.7%for the front car of the train adjacent to the mountain and increases by 16.5%for the rear car of the train away from the mountain.The impact of the mountain structures on the peak-to-peak values of a train’s lateral force is minimal when two trains intersect at the midpoint of the tunnel.Therefore,it is suggested to consider the placement of symmetrical buffer structures or the modification of existing mountain structures at appropriate locations near tunnel portals to mitigate the abrupt lateral force variations experienced by passing trains.
