Effects of platform sinking height on the unsteady aerodynamic performance of high-speed train pantograph

The aerodynamic forces of the high-speed train pantograph increase sharply with the increase in the operating speed. In this study, we simulated the unsteady aerodynamic performance of a high-speed train with the improved delayed detached eddy simulation (IDDES) method and analyzed the influence of the sinking height of the pantograph platform on the aerodynamic drag and lift coefficients of the high-speed train and pantograph. To verify the simulation model, the numerical results were compared with the wind tunnel test results, showing good agreement. The results indicated that the uncovered cavity formed by the pantograph platform sinking shielded the pantograph base frame to varying degrees, lowered the vorticity around it, but caused disturbances to the flow field near the train surface. The sinking platform of the pantograph effectively reduced the range and amplitude of the positive and negative pressure on the surfaces of pantograph base frame and cavity bottom. In addition, the pantograph drag and lift coefficients decreased with the increase in the sinking height. When the sinking height reached 500 mm, the aerodynamic drag and lift coefficients of the pantograph and the entire train decreased by 35.3%, 110.3%, 2.9%, and 21.4%, respectively.