Simulation of Flow around Collocated Bridge Piers with Pile Cap

Flow structure and vortical patterns around collocated bridge piers are inherently complicated. A comprehensive study of the flow pattern around bridge piers in groups provides proper information about the process of scour hole development around these structures. This study investigates the flow and velocity domain around these structures in solid beds and in beds with developed scour hole, numerically. The CFD code was calibrated using the experimental date from the literature and the velocity distribution and flow motion parameters were studied. Results indicate that the flow pattern beneath the pile cap is extremely complex with various patterns of vortices in different planes. Flow passing through the pile rows below the cap, interacts with the flow passes above the pile cap, forming a bilateral diving pattern behind the column and piles along with a strong spiral movement which results in the formation of a W-shape scour hole.