Analysis of train-induced aerodynamic characteristics and pressure-relief measures relating to fully enclosed noise barriers installed on railway bridges.

This article focuses on the aerodynamic pressure characteristics and mitigation strategies for fully enclosed noise barriers (FENBs) installed on high-speed railway bridges. Using a validated three-dimensional computational fluid dynamics (CFD) model, the study analyzes pressure distributions caused by single trains and two trains passing each other, revealing highly nonuniform pressure with peak positive and negative values significantly exceeding safety standards, especially at the mid-span of the 200 m barrier. The research identifies compression and expansion waves as primary contributors to pressure variations and demonstrates that encounters between two trains amplify these effects substantially. To address these issues, five passive pressure-relief hole schemes are proposed and evaluated, showing that multiple small relief holes spaced evenly along the barrier more effectively reduce peak pressures and produce a more uniform pressure distribution than single large openings, thereby enhancing structural safety without compromising noise reduction.