The Effect of the Working Height of Pantographs on Pantograph-Catenary Dynamic Performance

Computational fluid dynamics as a means of assessing the influence of aerodynamic forces on the mean contact force acting on a pantograph

“…In addition, a key role in determining aerodynamic uplift is played by the geometries of the pantograph's components 1 (e.g. collector section and articulated frame cylinders section), the working height 14 , and, as will be highlighted in the present work, the kinematic links between the vertical displacement of the pan-head and the displacements of the points where the aerodynamic forces act on each component. 2 Wind tunnel tests are a helpful tool for a first assessment of the aerodynamic properties of a pantograph, since they allow different solutions with known and controlled incoming wind flow to be tested.…”

Procedure to assess the role of railway pantograph components in generating the aerodynamic uplift

“…Stationary forces acting on pantograph components are able to change the mean value of the contact force, adding their contribution to the uplift force exerted by the pantograph raising mechanism at the bottom of the articulated frame (normally an air spring). This effect, indicated in the following as aerodynamic uplift, is dependent on train speed, pantograph working height [5] and orientation (modern pantographs have an asymmetrical geometry generating different aerodynamic uplifts in the two orientations in which they can operate). Moreover, the aerodynamic uplift varies when the pantograph enters a tunnel, due to the increase of the velocity of the relative flow.…”

“…With regard to the possibility of estimating aerodynamic forces on the entire pantograph, some authors have developed CFD models of a full-scale pantograph in a domain representing only the part of the carbody roof close to the pantograph [15], or CFD models of a pantograph installed on a full-scale train [16]. In [5], the authors underline the variability of the aerodynamic uplift force at different heights for both pantograph orientations, but no experimental results are presented. In [17], a fullscale pantograph is tested in a wind tunnel and the experimental results are compared with those of CFD models.…”

“…In [17], a fullscale pantograph is tested in a wind tunnel and the experimental results are compared with those of CFD models. In all the mentioned works, however, a complete validation of the CFD model against experimental results is not available, so that the capability of CFD to reproduce the aerodynamic uplift in an accurate quantitative way has not yet been completely demonstrated [18], [5], [17]. In this paper, the feasibility of using the RANS model is evaluated in order to seek the best trade-off between the achievable results and the computational effort, and to formulate a proposal that is also suitable for industrial applications.…”