Rail vehicles in crosswinds: analysis of steady and unsteady aerodynamic effects through static and moving model tests

This thesis presents the results of an experimental investigation of scale-model trains in crosswinds, undertaken to assess steady and unsteady aerodynamic effects of the vehicle movement simulation. A 1:25 scale-model train was tested in the University of Birmingham's TRAIN rig facility. A crosswind generator was designed and constructed to enable static and moving model experiments in the presence of crosswinds in this facility. An on­ board pressure measuring system comprising a series of miniaturised pressure transducers and a bespoke stand­ alone data logger were developed. Static and moving model experiments were carried out investigating a scale­ model of the Class 390 Pendolino train, on a nominal flat ground infrastructure scenario whilst subjected to a crosswind at 30° yaw angle. The test facility, measuring equipment and experimental methodology that were developed led to a more realistic underbody flow simulation and to a reduced margin of experimental uncertainty with respect to previous moving model tests. Furthermore, they enabled detailed surface pressure data to be measured, which are suitable for CFD benchmarking. The results support the reliability of wind tunnel tests on static vehicles for investigating steady aerodynamic coefficients but suggest that their use in the analysis of train unsteady aerodynamics is not entirely satisfactory