3D simulation of flow in a right angled channel junction with a pit

This study investigates 3D numerical simulation of open channel flow in a junction in the presence of a pit in its vicinity. A laboratory channel setup is considered for the present study. CFD software Fluent is used to simulate the 3D flow field. The numerical model is validated by comparing the simulated results for junction flow without a pit with the experimental results available in literature. In addition, simulations are performed for junction flow in the presence of a pit. Different locations of the pit are considered. Results for velocity field, water surface profile, flow separation zone, and energy loss are presented. Length and width of separation zone are reduced in the presence of the pit. Flow structure in the junction is most influenced when the pit is located at the junction. Lateral currents present at the downstream cross-sections and increased velocity past the forward step of the pit cause decrease of the spatial extent of the separation zone. Flow reversal occurs due to interaction of the high velocity and forward-facing step of the pit post channel junction. Energy loss is more in the presence of the pit. Pit location has no effect on energy loss. Strong upwelling flow reduces the water depression post junction section for the downstream pit location.