Mohamad Najafian, Javad Ahadiyan and Mohsen Solimani Babersad
Abstract
Bridges are of important connecting structures that are constructed on the rivers. Bridgespier is effective on the flow around the vortex formation and how they defeat the forces of inertia and consequently on the swinging forces into the base. In this study, the FLUENT model was used to simulate flow around the base about almost the real sizes. To verify the numerical model, Drag coefficient values and the Estrouhal number related to the simple cylinder base with the laboratory observations and previous research was reviewed and determined that the results from the turbulence model RNG k- to Reynolds number 2×105 are matched with the experimental results. Additionally the effect of geometry and slot position on vortex breakdown parameters including Drag and Lift coefficients were reviewed and based on the results of these coefficients, the best geometry and slot position that the intended forces are the minimum, were determined. The results showed that the Drag and Lift coefficients values for the optimized fractured mode compared with non-fracture mode in equal situations are reduced to 8.5% and 100% respectively. Increasing the slot length to width ratio is associated with a reduced coefficient of Drag and Lift and with the slot position depth reduction, Lift coefficient becomes close to zero.