3D Simulation of Flow Field in Vortex Settling Basin Using SSIIM Numerical model

Sediment transport in irrigation canals is an important issue in the design and operation of irrigation systems. The vortex‐settling basin (VSB) is a small scale, efficient, and economical device that using only the flow vortices to remove sediments. Most studies which explain flow patterns in VSBs are experimentally based on velocity measurements inside the VSBs in the laboratoary, and mathematical modeling studies are rare. The SSIIM model was used in this study to simulate the three-dimensional velocity distribution in a VSB, and the flow distribution obtained from available turbulence models in SSIIM were compared with experimental measurements. The results showed that the SSIIM model is able to capture the main features of the flow field, including the central vortex and secondary flows near the walls. The results also indicate that tangential velocity follows the combined Rankin vortex only in regions far from the inlet and outlet channels; however, this statement is not true in other regions. The k-ε turbulence model produces unacceptable results for the tangential velocity distribution, while both the tangential and radial velocity distributions obtained from the k-ω model are in reasonable agreement with laboratory measurements.