Validation of partially averaged Navier-Stokes and prediction for the turbulent flow past a generic high-speed train with and without yaw angle

Abstract

The paper presents a numerical investigation into the aerodynamic behaviors of a representative high-speed train model. A thorough comparison of external flow is carried out, involving Partially Averaged Navier-Stokes (PANS), Large Eddy Simulation (LES), and wind tunnel experiments. The train model is scaled down to 1/20 of its actual size. The Reynolds number for both simulations and experiments is fixed at Re = 2.45 × 10⁵, calculated using the inlet velocity U_inf = 20 m/s and the height of the train model H=0.18 m. Three different grid resolutions are utilized in the LES and PANS simulations. A comparison is made between time-averaged and instantaneous flow patterns, velocity, and Reynolds stress profiles under conditions both with and without a yaw angle. The findings indicate that PANS effectively captures the primary flow characteristics of the train’s external flow, with medium PANS closely aligning with fine LES and experimental measurements. Moreover, PANS surpasses LES at lower grid resolutions, showcasing the potential of PANS in effectively resolving the multi-scale instantaneous flow around the train model with relatively modest computational resources.