Flow pattern analysis and structure optimization of water distribution gate station hub

To address the issue of extensive flow backflow in the forebay during lateral diversion at a water diversion gate station hub, an optimization of the diversion wall parameters was conducted by integrating Response Surface Methodology (RSM) with Computational Fluid Dynamics (CFD). A regression model was established to correlate the wall’s geometric parameters with a comprehensive performance index ( y ), representing flow uniformity and efficiency. Numerical simulations revealed that due to the effects of viscous force and adverse pressure gradient, flow separation occurred on the boundary wall of the gradual change section. Meanwhile, within the constant-section forebay, the flow cross-section remained stable, velocity decay was minimal, and the extent of backflow showed negligible variation. The analysis of influence degree identified the pier head distance as the most significant parameter, followed by the pier tail distance and then the pier width. The optimal design, with a pier tail distance of 10.9 m, a pier width of 0.48 m, and a pier head distance of 2.38 m, achieved an optimal performance index value of 87.02%, corresponding to a remarkable improvement of 47.04% points from the original design value of 39.98%.