Numerical simulation of the protective effect of railway wind barriers under crosswinds

Abstract

Computational fluid dynamics (CFD) was employed for the simulation of a train model subjected to crosswinds. The numerical model was validated by comparing the flow structures and aerodynamic coefficients. A discussion of the protective effects of wind barriers at yaw angles in the range 0 < β ≤ π/4 is provided, along with an analysis of the flow distribution, and a proposal for a transformation of aerodynamic coefficients in the presence of wind barriers. The results show that the protective effect of a wind barrier for end nose are different for various yaw angle; the separation lines of the end nose at the leeward side of the vehicle bottom shift to windward in the presence of a wind barrier. The coefficients obtained through this transformation are found to be applicable for the side drag and lift coefficients of the head nose, which were obtained through numerical simulation, and are larger than the coefficients of the end nose at a majority of yaw angles. The yaw angle has a little effect on the absolute errors of the transformation for the end nose. The wind-reduction factor and absolute errors can be used to evaluate the protective effects of railway wind barriers to avoid the appearance of the different protective effect in a wind barrier.