Aerodynamic interference effects of bridge-train-like bluff bodies with small flow attack angle

This paper employs numerical simulation to examine the impact of variations in flow angle of attack (α) and low Reynolds number (Re) on the aerodynamic performance of the RC-TLBB (rectangle cylinder and train-like bluff body) system subjected to crosswinds. The RC-TLBB system consists of a train-like bluff body with a 5:1 cross section rectangle cylinder, and the rectangle cylinder cross section is used alone as a without-train group. The research indicates that the presence of the upper TLBB amplifies the influence of Re and α on the lift and drag of the rectangle cylinder. The alteration in α results in similar trends for both CL′ and C¯D of the TLBB and the rectangle cylinder. For Re, the trend is reversed. The rise in both α and Re enhances the correlation between the lift coefficient and drag coefficient. Nonetheless, the correlation between lift and drag coefficients exhibits greater strength for a rectangle cylinder in the system compared to a single rectangle cylinder in the without-train group. The presence of the TLBB spatially forces the separation of the shear layers, and the vortex shedding phenomenon on the upper side of the rectangle cylinder precedes that on the lower side at low Re. The increase in Re changes this phenomenon to the lower side preceding the upper side. This study illustrates the potential flow-induced problems by analyzing the various aerodynamic parameters of the system, which provides a theoretical basis for ensuring the safety and reliability of the system.