Abstract
Spillway design is key to the effective and safe operation of dams. Typically, the flow is characterized by high velocity, high levels of turbulence, and aeration. In the last two decades, advances in computational fluid dynamics (CFD) made available several numerical tools to aid hydraulic structures engineers. The most frequent approach is to solve the Reynolds-averaged Navier–Stokes equations using an Euler type model combined with the volume-of-fluid (VoF) method. Regardless of a few applications, the complete two-phase Euler is still considered to demand exorbitant computational resources. An assessment is performed in a spillway offset aerator, comparing the two-phase volume-of-fluid (TPVoF) with the complete two-phase Euler (CTPE). Both models are included in the OpenFOAM® toolbox. As expected, the TPVoF results depend highly on the mesh, not showing convergence in the maximum chute bottom pressure and the lower-nappe aeration, tending to null aeration as resolution increases. The CTPE combined with the k–ω SST Sato turbulence model exhibits the most accurate results and mesh convergence in the lower-nappe aeration. Surprisingly, intermediate mesh resolutions are sufficient to surpass the TPVoF performance with reasonable calculation efforts. Moreover, compressibility, flow bulking, and several entrained air effects in the flow are comprehended. Despite not reproducing all aspects of the flow with acceptable accuracy, the complete two-phase Euler demonstrated an efficient cost-benefit performance and high value in spillway aerated flows. Nonetheless, further developments are expected to enhance the efficiency and stability of this model.
Highlights
Spillways are essential for dam safety, controlling the reservoir water level and discharge, and preventing dam overtopping, one of the leading causes of structural failure and rupture
Which is reduced with higher mesh resolution
An assessment performed in a spillway offset aerator compares the two-phase volumeof-fluid (TPVoF) with the complete two-phase Euler (CTPE)
Summary
Spillways are essential for dam safety, controlling the reservoir water level and discharge, and preventing dam overtopping, one of the leading causes of structural failure and rupture. Such a crucial hydraulic structure requires careful design validation. A spillway is constituted by: intake, weir, chute, energy dissipation structure, and river restitution. The water flow from the reservoir approaches the intake in the subcritical regime with low velocity. Downstream, the chute flow is supercritical, with high velocities (frequently larger than 20 m/s), high levels of turbulence, and significant air entrainment and transport. At the end of the spillway, a structure dissipates energy, allowing proper restitution to the river stream. Surrounding and entrained air plays a crucial role in the safe operation of spillways [1]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
