Coupled Multibody-Aerodynamical Simulation of High-Speed Trains Manoeuvres

The effects of aerodynamical loads on the driving dynamics of high speed trains during common manoeuvres have been investigated. To this end a co-simulation MBS/CFD was implemented. A linear aerodynamical model, the panel method, was applied to the computation of the unsteady flow around the driving trailers for the examined manoeuvres in absence of cross wind. The multibody simulation program SIMPACK simulated the dynamical response of the vehicles to the resulting aerodynamical loads. Coupled and uncoupled simulations have been performed. In the uncoupled simulation the aerodynamical loads are computed on trains moving rigidly according to the nominal prescribed driving velocities. The small motion of the trains due to the aerodynamical loads is thus neglected in the aerodynamical subsystem. In the coupled simulations displacements and velocities computed by the multibody code at every time step as effect of the aerodynamics loads are passed back to the aerodynamical code and are embraced in the aerodynamical simulation of the next time step. The effect of operative conditions (different driving velocities, symmetrical and asymmetrical passing manoeuvres) and of environmental conditions (operations on open track or at tunnel entrance) have been investigated, according to the modelling limits imposed by the linear aerodynamical model