Visualization Study Of The Influence Of Parapets On The Flow Around A Train Vehicle Under Cross Winds
Free (open access)
797 - 806
M. A. Barcala & J. Meseguer
Aerodynamic loads on train vehicles under cross winds are governed both by the shapes of the vehicles and of the surroundings. Aerodynamic loads due to cross winds are of paramount importance in the lateral equilibrium of the vehicle, in such a way that if the lateral wind speed becomes larger than a threshold value the overturning of the vehicle can take place. The degree of danger against overturning increases when the train is on a bridge, the reason being that the velocity in the atmospheric boundary layer grows as the height increases, leaving aside the fact that at ground level there may be other elements acting as windbreaks (mainly vegetation). The effects of different types of parapets, either solid or porous, on the wind protection of a train vehicle on a bridge under cross wind have been visualized by smoke wind-tunnel tests. In addition the effects of several types of solid parapets on the side force and rolling moment acting on a two-dimensional model of the same high-speed train coach have been measured by wind-tunnel pressure measurements. Experimental results show that, as one could expect, solid parapets seem to be more effective than porous ones, and the aerodynamic loads decrease as the height of the windbreak increases. Keywords: flow visualization, train aerodynamics, wind tunnel tests, overturning of train.
flow visualization, train aerodynamics, wind tunnel tests, overturning of train.