Nonlinear aerodynamic loads and dynamic responses of high-speed trains passing each other in the tunnel-embankment section under crosswind

The nonlinear aerodynamic loads and dynamic responses caused by the crosswind when two trains pass each other are extremely complex, and guaranteeing safety under these circumstances is difficult. To compare the difference in nonlinear loads and dynamic response between one train and two trains passing each other under crosswinds, the renormalization group k-epsilon turbulence model and the mosaic grid technology are used to establish a variety of 3D numerical models of train-tunnel-embankment. The variation law of aerodynamic load in the numerical model is highly consistent with the test data, and the maximum error is less than 7%. First, the aerodynamic performance differences are compared with the aspects of nonlinear load amplitude and power spectral density, and the difference mechanism is disclosed by the flow field. Then, based on a segmental loading method, a coupled dynamic response analysis model (wind-train-tunnel-embankment) is used to analyze the difference rule of the derailment coefficient and the rate of wheel load reduction (RWLR). The key conclusions are as follows: the pulse impact produced by trains meeting aggravates the aerodynamic load amplitude. The amplitude of rolling and yawing moments on the head train increases by 78.31% and 30.88%, respectively. When the crosswind speed exceeds 20 m/s, the RWLR enters the dangerous zone.

Automated summary

The nonlinear aerodynamic loads and dynamic responses caused by crosswind when two trains pass each other are complex and ensuring safety is difficult. A variety of 3D numerical models of train-tunnel-embankment are established using the renormalization group k-epsilon turbulence model and the mosaic grid technology. The variations of aerodynamic load in the numerical model are consistent with the test data, with a maximum error less than 7%. The difference in nonlinear loads and dynamic response between one train and two trains passing each other under crosswinds is compared, and the difference mechanism is disclosed by the flow field. Based on the coupled dynamic response analysis model (wind-train-tunnel-embankment), the difference rule of the derailment coefficient and the rate of wheel load reduction (RWLR) is analyzed using a segmental loading method. The pulse impact produced by trains meeting aggravates the aerodynamic load amplitude, and the amplitude of rolling and yawing moments on the head train increases by 78.31% and 30.88% respectively. When the crosswind speed exceeds 20 m/s, the RWLR enters the dangerous zone.