Numerical Study on the Hydrodynamic Optimization of Bridge Pier Collision Protection Facilities: Effects of Flow Diversion Angles Using RANS Model

Abstract goes here. This study utilizes the Reynolds-Averaged Navier-Stokes (RANS) turbulence model to numerically investigate the hydrodynamic characteristics of pier collision protection structures. Through computational fluid dynamics (CFD) simulations, the effects of various flow diversion angles on hydrodynamic performance were systematically analyzed. Results identify a diversion angle of 60 degrees as the optimal configuration for pier collision protection facilities, significantly enhancing flow characteristics around the pier and improving hydrodynamic efficiency. At this angle, the maximum flow velocity is reduced by 14.2% compared to 150 degrees, with low-speed vortices eliminated and a stable triangular low-speed region formed. The pressure differential and drag coefficient reach their lowest values, while lift and drag coefficients are reduced by approximately 88.4% and 76.2%, respectively. Furthermore, the vortex shedding frequency and Strouhal number are markedly reduced at 60 degrees, transitioning the wake from an oscillatory to a stable state. The Strouhal number, which is more sensitive to changes in diversion angle than flow velocity, achieves a minimum value of 0.0240 at 60 degrees—a 90.6% reduction compared to 150 degrees. These findings offer valuable insights for optimizing bridge pier designs, contributing to improved structural safety and hydrodynamic performance, with potential applications across civil engineering, marine engineering, and environmental protection.