Author(s): Monica Moroni; Myrta Castellino; Fabio Sammartino; Paolo De Girolamo

Linked Author(s): Monica Moroni

Keywords: Hydraulic structure; CFD; Laboratoy experiments; Dams

Abstract: The investigation of the safety conditions of large hydraulic infrastructures such as dams is of great interest for safeguarding territories and assessing their risk level. This is especially true due to the occurrence of extreme events caused by climatic change, which motivates the reaudit of hydrological basins for various purposes, such as to verify the suitability of the spillways and outlets of existing dams to withstand any increase in the design flow. Issues related to the design and verification of infrastructures interacting with fluids in motion may be tackled numerically with Computational Fluid Dynamics (CFD) and experimentally with physical models. The remarkable technological advances of the last decades have made it possible to develop increasingly refined numerical models, allowing the study of the temporal evolution of the fluid with a spatial resolution which can be very high. Nevertheless, physical modeling still represents a mandatory tool for verifying and calibrating the results provided by numerical models. This paper describes the 1:60 Froude scaled numerical model of the Liscione (Guardialfiera, Molise, Italy) dam spillway and the downstream stilling basin. The k-ω SST turbulence model was chosen for closing the Reynolds Averaged Navier-Stokes equations (RANS), since in simulations involving similar geometries, it has shown a remarkable robustness and reliability. The Autocad software was used to construct the geometry of the computation domain whereas the simulations were performed with the ANSYS Fluent software. The discretization of the domain was performed via the software supported by Fluent and provided by ANSYS (Fluent Meshing), which guarantees the generation of a simply connected domain (Watertight Geometry). Experimental data have been gathered from the 1:60 scale physical model of the Liscione dam spillways and the downstream riverbed of the Biferno river built at the Laboratory of Hydraulic and Maritime Constructions of Sapienza University of Rome. The model is scaled according to the Froude number and fully-developed turbulent flow conditions have been reproduced at the model scale (Re > 10,000). From the analysis of the results of both the physical and the numerical models it is certainly clear how the dissipation tank is undersized and therefore insufficient to manage the energy content of the current output to the river. Therefore, the flow is introduced into the riverbed with a high energy content, which impacts on an erodible bottom.

DOI: https://doi.org/10.3850/IAHR-39WC2521711920221465

Year: 2022