Interaction Simulation of a Lateral Wall Distance on Aerodynamic Characteristics of a Simplified High-speed Train

Abstract

The natural features, such as mountain slopes, cliffs, and the human-made artificial walls, such as train station walls, windbreakers, and even residential and office buildings, can affect the movement structure of high-speed trains. In the present paper, using computational fluid dynamics (CFD), the interaction of lateral wall distances on the aerodynamic characteristics of a high-speed train is simulated. To achieve this -using OpenFOAM- the governing equations are solved. Also, the used solver is simpleFoam which the Simple algorithm (Semi-Implicit Method for Pressure Linked Equations) is applied to decouple the Navier-Stokes's equations. In the following a simplified high-speed train is considered, combining Reynolds-Averaged Navier-Stokes (RANS) equations and k-ω (SST) turbulence approach, an incompressible turbulent air-flow around it is simulated. Also, the flow and aerodynamic structures affected by distance changes between the lateral wall and the train are analyzed. Therefore, the lift, drag, and side aerodynamic forces and their corresponding moments as pitching, yawing, and rolling are provided and compared for four distance cases. In the following, the most significant components of flow structure, such as streamlines, velocity and pressure distributions, and vortices structures, are discussed. Finally, using the turbulent kinetic energy analysis, the air-flow's turbulent level around the train, especially in critical areas, is investigated. The findings illustrated that the closer distance between the train and the wall has more destructive effects on the movement of the high-speed trains. The results of the present study can be helpful for designing structures along the rail and distancing it from natural features.