Analysis of the unsteady loads on train models in windtunnels

Abstract

Climate change leads to adverse weather and wind conditions. These condi-tions may result in high loads on ground vehicles, especially trains and cars. For trains, crosswind forces as well as drag are subject to research. However, the study of unsteady loads requires extensive simulation of the unsteady in-coming flow conditions. Within the work presented in this paper, the loads on two different train models were analyzed experimentally using a specialized technique of gust generation in the wind tunnel. The loads were studied depending on the fre-quency and amplitude of sinusoidal gusts. The tests showed that mean loads measured with unsteady wind conditions exceed the loads during steady wind conditions in most specific test parame-ters. Especially the frequency of the gusts is crucial for the drag and cross-wind forces. The drag rises with increasing gust frequency. The crosswind forces have a maximum for a certain frequency. For this frequency, the wavelength of the gusts equals the train length leading to higher loads. In up-coming tests the influence of the gusts on the crosswind forces and the drag will be studied with an initial rotational angle of the train model.