Simulating the flow around a train passing through a tornado

A flow simulation was developed to understand the flow surrounding a train that was passing through a tornado and the resulting aerodynamic forces acting on the vehicle. Unsteady Reynolds averaged Navier-Stokes equations were solved to reproduce a previously-conducted laboratory experiment, in which a model train runs through a stationary tornado-like swirling flow. The simulation reproduced the unsteady aerodynamic forces acting on the train reported in the experiment. Furthermore, the computation successfully revealed how the flow field changes as a train passes through a tornado-like swirling flow.