Aerodynamic characteristics of the train-SENB (semi-enclosed noise barrier) system: A high-speed model experiment and LES study

The aerodynamic effect of a passing high-speed train (HST) may cause structural damage to the semi-enclosed noise barrier (SENB). Moreover, the rapid variation of the aerodynamic environment may deteriorate the operation stability of the train and passenger comfort. Three types of rectangular SENBs, namely, inverted -L-shaped noise barriers installed on double-line railways (ILSNB-DL), inverted-L-shaped noise barriers with a vertical board installed on double-line railways (ILSNBVB-DL) and inverted-L-shaped noise barriers with a vertical board installed on single-line railways (ILSNBVB-SL), are considered in this research. By establishing a 1:16.8 train-SENB moving-model system and a corresponding large eddy simulation (LES) model, the time -history and spatial characteristics, flow field mechanism and spectral characteristics of the aerodynamic pres-sure acting on the three types of SENBs are investigated. Moreover, the differences in the time-history charac-teristic, flow field mechanism and spectral characteristic of the aerodynamic loads on the HST when passing through the three types of SENBs are also compared. The aerodynamic pressure inside ILSNBVB-DL is more than 27% higher than that of ILSNB-DL, and the aerodynamic pressure inside ILSNBVB-SL is more than 16% higher than that of ILSNBVB-DL. When the HST enters and exits ILSNBVB-SL, the area with positive and negative pressure on the train surface varies the most dramatically, causing the amplitude of the lift force of the HST when passing through ILSNBVB-SL being approximately four times the value when the HST passes through ILSNB-DL and ILSNBVB-DL. When the HST enters and exits ILSNB-DL and ILSNBVB-DL, the pressure difference between the two sides of the HST is greater than that when the HST enters and exits ILSNBVB-SL, leading to the maximum amplitude of the side force of the HST passing through ILSNB-DL being 1.8 times of the value for ILSNBVB-DL and ILSNBVB-SL.