Optimization of Deflector–Groove Aerator Location for Cavitation Mitigation on Spillway Chutes: A CFD-Based Investigation
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Cavitation in high-velocity spillways is a critical issue in modern hydraulic design, particularly in channels with downward concave vertical curvature, which are vulnerable to negative pressure and jet reattachment. This study aims to evaluate the influence of aerator position, using a deflector-groove type, on flow characteristics, pressure distribution, entrained air mass, and the cavitation index in a multi-slope spillway through CFD-based numerical simulation. Five aerator configurations, labeled A to E, were analyzed under a design discharge of 1,154.3 m³/s, using the SST k–ω turbulence model and mesh sizes ranging from 220 to 500 mm. Validation against physical data showed a high level of significance, with R² > 0.9, confirming the reliability of the numerical model used. The velocity distribution indicates that the aerator location significantly influences air-jet formation and air-cavity stability. The aerator positioned at the center of the concave section, Series A, produced the most stable flow pattern, controlled negative pressure, and an entrained air mass of 63 kg/s. In addition, the cavitation index value for Series A showed an average increase of up to 20% compared with the other configurations, indicating the effectiveness of this position in reducing cavitation potential. Based on the integrated results of pressure, aeration, and cavitation index, the Series A configuration is recommended as the optimal position for spillways with a downward concave vertical curve geometry. This finding reinforces the established aeration theory reported in previous studies and provides a practical contribution to the optimization of aerator design in complex spillways.
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