The purpose of this study is to investigate the acceleration effect, known as the Venturi effect, which occurs when natural wind flows over locally narrowed gorge-ridge terrain, and to assess its significant deterioration of high-speed train aerodynamic performance.
The study employs an integrated methodology of field measurements and numerical simulations. It provides a systematic analysis of the natural wind field characteristics in real gorge terrain and the resulting aerodynamic response of trains. The approach explores the mean and fluctuating wind properties, clarifies the influence of ridge contraction ratio on aerodynamic loads, train surface pressure and power spectral density, and establishes a three-dimensional relationship between train speed, fluctuating wind speed and aerodynamic load amplitude.
The wind field in the gorge’s bridge-tunnel section shows strong crosswind and nonstationary characteristics, with terrain altering turbulence structure. Ridge contraction ratio critically influences transient aerodynamic load changes; increasing contraction ratio from 0.3 to 0.7 raises the leading car’s load coefficient amplitude by 16.96% to 53.02%. This intensifies the Venturi effect, causing a larger train-side pressure difference, increased vortex separation, higher turbulent kinetic energy and severe load fluctuations and degraded operational stability. aerodynamic load amplitude exhibits a positive coupling with train speed and fluctuating wind speed, with train speed being the more dominant factor.
This study provides a novel, comprehensive analysis by uniquely integrating field and simulation data for real gorge terrain. It delivers original insights by quantifying the impact of ridge contraction ratio and establishing a key three-dimensional operational-environmental relationship. The revealed flow mechanisms offer direct theoretical and engineering support for safety assessment and wind protection design of high-speed railways in gorge areas.
