Train aerodynamic forces and moments from moving model experiments

Abstract

Conventional static low turbulence wind tunnel experiments on model trains do not correctly model the effect of atmospheric turbulence or train/ground relative motion. To overcome these shortcomings, experiments have been carried out in which a 1 50 model advanced passenger train was catapulted across a wind tunnel in which an atmospheric boundary layer had been simulated. This paper describes the very considerable experimental difficulties that were involved, and in particular the simulation of the atmospheric boundary layer, and the difficulties in interpreting the results of this simulation. Results are presented for side and lift force coefficients and points of action for the leading three cars of the model APT set with the model passing over both a model embankment simulation and over a level ground simulation, and an attempt is made to explain the variations, in the results that were obtained. The effect of wind fences on the coefficients was also investigated.