Author(s): Seyedahmadreza Saeidihosseini; Mostafa Taherian; Abdolmajid Mohammadian

Linked Author(s): Mostafa Taherian

Keywords: Large eddy simulations; Negatively buoyant jets; Multiport diffusers; Turbulence modeling; Mixing characteristics

Abstract: Brine effluents are commonly discharged into water bodies through diffusers and may cause almost permanent adverse effects on marine habitats. Since the extension of such negative effects closely depends on the features of the outfall diffusers, it is essential to predict the mixing behavior of the jets for different types of diffusers. Although single-port discharges are theoretically superior in terms of mixing efficiency, currently, multiport diffusers are frequently applied due to the limitations in practical projects. The mixing behavior of multiport discharges compared to single-port ones is much more complicated because of the complex mechanisms resulting from jet interaction and the Coanda effect. Most of the numerical studies on discharges have focused on single-port discharges, and less attention has been given to the multiple jets. Also, the limited available numerical studies on the multiport diffusers have applied the Reynolds-averaged Navier-Stokes (RANS) turbulence models. In this study, the dilution and geometrical characteristics of the multiple 60o inclined dense jets were numerically investigated in detail using the large eddy simulation (LES) approach with the Smagorinsky subgrid-scale (SGS) model. The LES predictions for the impact point location, impact point dilution, and terminal rise height were compared to the existing measurements in the literature. The results showed that the LES outcomes were in good agreement with the experimental data, and the LES approach was found to be a reliable tool for the investigation of multiport diffusers. The merging process of discharges was also studied based on the presented model.

DOI: https://doi.org/10.3850/IAHR-39WC252171192022809

Year: 2022