Two-phase Euler modelling of hydraulic structures

Abstract

The Two-Phase Euler model, implemented in the twoPhaseEulerFoam solver of OpenFOAM v2412, is applied to flows within and adjacent to hydraulic structures where aeration and energy dissipation are fundamental. Three representative cases are investigated: an impinging jet, a headcut jet, and a spillway chute with stilling basin. This assessment is of utmost importance for hydraulic engineering researchers and practitioners, because the Volume-of-Fluid method (VoF) is still frequently applied in flows with significant air-water mixing, despite tending to null aeration as mesh resolution increases, which leads to unrealistic results. In contrast, the Complete Two-Phase Euler model - despite still being considered computationally demanding and sensitive to numerical instability - addresses several limitations of the VoF approach and offers a more reliable cost-benefit performance. It is particularly suitable for simulating high-velocity, high-turbulence, and intensely aerated conditions typical of many hydraulic structures. This work aims to promote the adoption of the Complete Two-Phase Euler model in the hydraulic engineering community. Three case studies are presented and made publicly available through an open repository, contributing to transparency, reproducibility, and further development.