Hydrophysics

Hydrophysics

Two-Dimensional Numerical Modeling of Flow in the Physical Model Scale of the Karun River (Upstream of the Jangieh Meander)

Document Type : Original Article

Authors
Alireza Sadigh 1
Mehdi Ghomeshi 2
Mohammadreza Zayeri 3
1 PhD student of water structures, Faculty of Water and Environmental Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran
2 Professor, Department of Hydraulic Structures, Faculty of Water and Environmental Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
3 Assistant Professor, Department of Hydraulic Structures, Faculty of Water and Environmental Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran
Abstract
Recent advances in computational power and numerical methods have greatly improved the accuracy of modeling water flow and sediment transport processes. This study explores the application of the two-dimensional numerical HEC-RAS model to predict hydraulic parameters in a river meander, validated against a physical model of the Karun River at the Jangieh meander. The modeled reach extends 40 km from Ahvaz to Farsiat and includes measurements of water surface elevation and flow velocity. Results demonstrate that the numerical model accurately reproduces flow velocity patterns similar to those observed in the physical model, with performance metrics of R² = 0.941, RMSE = 0.04 m/s, and Nash–Sutcliffe Efficiency (NSE) = 0.88. Mesh characteristics significantly influenced velocity distribution accuracy, with high-resolution regular grids providing the best simulation results. Appropriate simulation duration and time step selection were critical, with a typical time step of 0.5 seconds used in most simulations. Additionally, analysis of satellite imagery spanning the last 51 years indicates that the riverbanks in the Jangieh meander region are prone to erosion due to elevated shear stress. These findings underscore the importance of integrated hydraulic and sediment monitoring for sustainable management of meandering rivers.
Keywords
Numerical Modeling
Physical Model
Meander
Karun River
Satellite Imagery

Subjects

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  • Receive Date 25 December 2024
  • Accept Date 06 January 2025