Author(s): Wang Zhi; Li Manjie

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Keywords: Saltwater intrusion Subgrid 2D Flow resistance method Discrete term

Abstract: Salinity represents a pivotal parameter in the management of ecosystems and water quality in tidal rivers. The hydrodynamic conditions and turbulence characteristics of the river fundamentally influence the processes of mixing, diffusion, and transport of salinity. Consequently, it is imperative to accurately model the relationships among salinity, turbulence characteristics, and hydrodynamic conditions. This study presents a predictive model designed for salinity in tidal rivers, which incorporates an enhanced two-dimensional grid method (Subgrid2D), a flow resistance method (FRM), and a depth-averaged turbulence model. Additionally, to improve the model’s accuracy in scenarios where velocity distribution across the width of the river is non-uniform, a discrete term is integrated into the salinity transport equation. The analysis further explores the correlation between salinity distribution and various flow characteristics, including velocity, Reynolds stress, and turbulent kinetic energy. Comparative assessments with empirical data indicate that the developed numerical model significantly improves computational accuracy and robustness while preserving the computational efficiency. Furthermore, the distributions of velocity, Reynolds stress, and turbulent kinetic energy demonstrated strong correlations with salinity distribution. The findings from this computational study shed light on the influences of saline intrusion on the water quality of riverine systems, thereby establishing a theoretical and modeling basis for the water environment management.

DOI:

Year: 2025