Marojahan L. Gaol, Pitojo T. Juwono, Very Dermawan, Dian Sisinggih, Lily M. Limantara
This research intends to build a 3-D flow model of a section of the spillway chute at Tigadihaji Dam under the spillway design flood with a 1000-year return period, to investigate flow behaviour and the potential of cavitation damage using a numerical model in Ansys Fluent. The numerical model is validated against a physical model, and the impact of the aerator on the chute is also assesses. The research parameters are velocity, pressure, and cavitation number, obtained from the measurements at 16 points along the chute. The methodology consists of modelling and validation. The modelling was carried out for the chute and the chute with an aerator. The validation of computational fluid dynamics (CFD) model, based on pressure data, produced a determination coefficient (R2) of about 0.97. It shows that the CFD model is very good in presenting the trend and fluctuation of physical data. The cavitation analysis at Q1000 indicates a moderate risk in chuteway-3 and a high risk in chuteway-4. To mitigate this, a deflector–offset aerator was installed at the slope transition from 1:35 to 1:1.5. The simulation results reveal an increase of up to 0.1 in the cavitation index, with improvements extending about 20 m downstream of the aerator. Nevertheless, the offset section on the milder curved profile limited performance due to incomplete aeration. © 2026. The Authors.
University of Brawijaya, Doctoral Program in Department of Water Resources, Faculty of Engineering, Jl. MT Haryono No. 167, Malang, 65145, Indonesia; University of Brawijaya, Faculty of Engineering, Department of Water Resources, Jl. MT Haryono No. 167, Malang, 65145, Indonesia
