Crosswind action on rail vehicles: A methodology for the estimation of the characteristic wind curves

The problem of cross wind for rail vehicles gained, in the last years, an increasing interest whithin the European railway operators, due to the continuous expansion of the high-speed railway networks. In order to evaluate the aerodynamic performance of a train in terms of safety towards cross wind, the Characteristic Wind Curves (CWCs), have to be defined. In this paper a stochastic approach for the definition of the CWCs is presented. According to this methodology, the wind speed space-time distribution is reproduced through a stochastic process and the algorithm for the definition of the aerodynamic loads acting on the train is set up, which is based on the admittance function. A numerical model for the admittance function is presented and verified by means of comparison with experimental data. The effects of the admittance function and of the stochastic approach in the definition of aerodynamic forces and of the corresponding CWCs are then analysed in terms for a specific case (assigned reference train, flat ground scenario, tangent track running).