Research On Impact Of Cut Forms On Train Aerodynamic Performance And Mitigation Measures

The railways in Xinjiang province of our country are buffeted by the strong wind all the year round, and the local landforms along the railway are complex and constantly shifting, so that it produced different cutting forms. It’s found by site investigation that the special forms of cutting always causes to increase the aerodynamic forces of the train sharply due to the various gradients, depthes and the landforms of the leeward side of cutting. Therefore, it’s very important to research the influences on the aerodynamic forces of the train under strong wind, caused by the various cutting forms, and also important to study on the optimization of wind-break facilities in dangerous areas to guarantee the safety of train-running.Based on numerical simulation results, this paper analyses the aerodynamic performances of the train under strong wind in cuttings of different forms, and makes an optimization proposal of wind-break facilities in dangerous areas, to lead to the following conclusion:(1) In a symmetric cutting, the aerodynamic forces of the train decrease with the increase of the gradient and depth of the side slope. In a non-symmetric cutting, the aerodynamic forces of the train increase sharply during the landform of the leeward side shifting from uphill to flat, and then downhill. On a slope of mountain, the aerodynamic forces of the train increase with the increase of gradient and decrease with the increase of the height of the cutting. In the areas of the particular landforms mentioned above, the aerodynamic forces of the train all increases with the increase of the wind angle.(2)The relationship between the aerodynamic forces of the train and wind angle, gradient of the slope, height of the side slope, depth of cutting, gradient of cutting and the landform of the leeward side of cutting can be described below:CMx=(αβ3+bβ2+cβ+d). The various landform parameters can be reflected by different coefficients, which provide the basis to determine the aerodynamic performances of the train in various landforms.(3) The reasonable height of windbreak on different landforms has been obtained. The optimal height of the windbreak corresponding to a slope of5°,10°,15°,20°is1.5m,2.0m,2.5m,3.0m, and1.0m for the particular cuttings.All these research achievements provide scientific basis for further study on critical speed of the wind and train for overturning.