Nonlinear aerodynamic effects of three new types of high-speed railway acoustic insulation facilities using a model experiment and IDDES

Three new types of acoustic insulation facilities, namely, full-enclosed (FEAB), bilateral-inverted-L-shaped (BILSAB), and inverted-L-shaped (ILSAB) acoustic barriers, are gradually receiving application along high-speed railways. A moving high-speed train (HST) may induce a nonlinear aerodynamic impact on the acoustic barrier. The HST may also experience a rapid change in its aerodynamic loads, reducing its stability and causing discomfort to passengers. Hence, nonlinear aerodynamic effects of three new types of high-speed railway acoustic insulation facilities when an HST passes by are compared based on model experiments and improved delayed detached eddy simulations (IDDES). Results show that: (i) When a HST runs at 350 km/h, the coefficient of pressure difference on the FEAB is 5.64 and 8.78 times higher than in the BILSAB and ILSAB, respectively. (ii) The amplitude of drag force coefficient of the head car when entering the FEAB is 2.80 and 2.95 times that of the BILSAB and ILSAB, respectively. The amplitude of lift coefficient of the tail car when running through the BILSAB is 1.27 and 1.37 times that of the FEAB and ILSAB. The amplitude of side force coefficient of the tail car when running through the ILSAB is 1.18 and 1.24 times that of the FEAB and BILSAB. (iii) For the tail car, the standard deviation of C_x when running inside the FEAB is 2.18 and 2.15 times that of the BILSAB and ILSAB, respectively. The standard deviation of C_y when running inside the FEAB is 1.42 and 1.51 times that of the BILSAB and ILSAB, respectively. The standard deviation of C_y when running inside the FEAB is 1.48 and 1.15 times that of the BILSAB and ILSAB, respectively. The results of this research may provide reference value for optimizing the structural patterns and improving the train’s operating stability.