Abstract
Methods for reducing lift force of conventional pantographs in a crosswind were investigated using large-eddy simulations (LESs). In our previous study, wind tunnel tests and numerical simulations using a full-scaled pantograph were carried out, and the mechanism how the lift force increase in a crosswind was clarified. There are mainly two mechanisms: one is a stational large-scale vortex generated on the upper surface of the pantograph head, and the other is positive pressure generated on the lower surface of the pantograph head. In this study, LESs were carried out using a modified pantograph head shape based on the mechanisms described above, in order to investigate methods for reducing the lift force of the pantograph head. As a result, the lift force decreased in the cases of a shape with a diagonal cut on the lower surface of the pantograph head, and a shape with an opening sections on both the upper and lower surface of the pantograph head. The former shape generates a negative pressure area under the pantograph head, while the latter shape attenuates the large-scale vortex on the upper surface of the pantograph head. Thus, they achieve the lift reduction by different mechanisms and can be used together. The lift reduction rate reaches approximately 60% when both methods are used together, indicating that this is an effective method for lift force reduction.
