Grundlagen für ein neues Modell des Luftwiderstands von Eisenbahnfahrzeugen.

In order to calculate, simulate, and optimize the energy demand of train runs, the running resistances have to be modeled. Mostly, simplified - e.g. the Davis equation - or approximated formulas for part resistances are used. This also applies for the aerial resistance: for cw value, effective surface area, air density, and relative air speed, either approximate or norm values are used in general. Contrariwise, aerodynamic investigations show that the aerial resistance does not decay with the cosine of the increasing yaw angle as the use of relative air speed indicates; in contrast, the aerial resistance increases up to a yaw angle of 60°. In this paper, a numerical model including this phenomenon is presented; moreover, wheel flange contact occurrence as consequence of side wind forces is discussed. The presented case studies confirm that the wind and its yaw angle may have a relevant influence on the energy demand. [ABSTRACT FROM AUTHOR]