Numerical simulation of the turbulent flow around a complex bridge pier on the scoured bed

Abstract

The present study aims to contribute to the numerical simulation of the flow behavior around a complex bridge pier with the scoured bed. For this purpose, a custom Large Eddy Simulation model was developed in which the pier and bed geometries are modeled in a structured grid system with orthogonal grid lines. The top free surface was treated as a shear-free rigid-lid. Moreover, a wall function was employed at the wall boundaries to consider the wall roughness effect on the predictions. This way, reliable numerical simulations could be performed at high Reynolds numbers with low computational cost. The developed numerical model was firstly validated by considering two cases (flow over periodic hills and flow around a single bridge pier on a scoured bed) and then the model was applied to a complex bridge pier for a scoured bed. The obtained numerical results were found to be in good agreement with the corresponding experimental and numerical results. Moreover, this study enabled to characterize the most relevant flow features of the studied cases. Overall, the highest values of the flow parameters and the small flow structures were numerically predicted in the regions where no experimental results are available due to measuring instruments limitations. According to the obtained results, the present numerical model can be considered as an adequate tool to investigate the turbulent flow features near complex geometries in a simple, fast and accurate way.