Optimization of geometrical parameters and hydraulic performance assessment of sheet pile submerged vane

Submerged vanes are passive river-training structures used to redirect near-bed flow, generate secondary circulation, and regulate sediment transport without causing large flow obstruction. This study presents a systematic hydraulic characterization and geometrical optimization of a corrugated Larsen type sheet pile submerged vane as a practical alternative to conventional smooth flat vanes. A scaled Larsen 603 K sheet pile profile was examined through laboratory experiments and OpenFOAM-based numerical simulations using the Reynolds-averaged Navier–Stokes equations with the shear stress transport k−ωSST turbulence model. Sixteen configurations were systematically evaluated by varying relative vane height (d/h = 0.3–0.4, where d = vane height, h = flow depth) and attack angle (α=10°−40°) to quantify their combined influence on hydraulic performance and to provide a quantitative basis for refining the geometrical design of sheet pile submerged vane. The numerical model was validated against acoustic Doppler velocimeter measurements and used to analyze pressure distribution, hydrodynamic coefficients, mean velocity, secondary flow, bed shear stress, turbulent kinetic energy, and coherent vortical structures. The sheet-pile vane geometry was optimized using the weighted sum method, which identified d/h=0.4 and α=30° as the configuration providing maximum balanced hydraulic performance. The results show that the additional roughness of the sheet pile geometry enhances key near-bed flow features by promoting local flow separation, shear layer interaction, and small-scale vortical motion. These roughness induced effects strengthen secondary circulation, redistribute bed shear stress, and improve the potential of the vane for sediment diversion and scour mitigation.