Author(s): Puja Kumari; Abhishek Pandey
Linked Author(s):
Keywords: Deformed Bed Channel junction CFD Flow circulation RANS
Abstract: Natural junctions like river confluence have generally uneven or irregular beds due to various factors such as sediment deposition, erosion, or human interventions. Understanding of the flow structures of such open-channel deformed bed junctions is still limited despite considerable research on channel junctions. Investigations of the flow structures at a deformed bed junction help better understand the movement of sediment and pollutants through river networks, flood risk assessment, and water resource management. To this end, a right-angled channel junction with a deformed bed consisting of the scour zones and deposition bars is considered in the present study. The deformed bed represents the quasi-equilibrium conditions, obtained from the initial flat and horizontal bed conditions. The study of flow structures is conducted using the computational fluid dynamics (CFD) software ANSYS 2022 R1. The numerical model employs three-dimensional (3D) transient Reynolds-averaged Navier-Stoked (RANS) equations, with the Reynolds stress model (RSM) as a turbulence closure. The volume of fluid method is employed to compute the water surface elevation. The current numerical model is validated using the laboratory data from published experimental studies. Comparisons of the flow field show that the model reproduces the experimental data satisfactorily. The current study compares the detailed 3D flow structures between quasi-equilibrium deformed bed junction and flatbed junction. The simulated results show the significant role of the deposition bar in modifying the flow circulation at the junction downstream. Additionally, the various other characteristics junction flow structures are also significantly influenced due to the bed deformations.
Year: 2025