A NUMERICAL STUDY OF THE MAXIMUM SCOUR DEPTH AROUND INCLINED BRIDGE PIERS AND COMPARISON WITH AN EXPERIMENTAL MODEL

M. GHASEMI ASL, M. HEIDARNEJAD

Abstract


Local scour holes develop around bridges due to the flow coming into collision with the piers and the resulting flow separation. The scour hole dimensions around bridge piers depend on flow hydrodynamics, fluid properties, pier geometry, and bed-load properties. Accordingly, this study numerically investigates the maximum scour depth around inclined bridge piers using FLOW 3D and compares the results with an experimental model. The maximum vertical flow velocity was found to increase by 50% by increasing the Froude number (Fr) from 0.49 to 0.73. Furthermore, the vertical flow velocity was reduced by 41% on average by increasing the bridge pier inclination from 0 to 15°. The results indicate that increasing the pier inclination from 0 to 15° reduces the average maximum scour depth by 28.2, 21.6, 18.5, and 20% at 12, 14, 16, and 18 l.s-1 flow rates, respectively. The scour is exacerbated by increasing the flow rate. Increasing Fr from 0.49 to 0.73 leads to an average 18% increase in the maximum scour depth. The results are suggestive of a 3.4% difference between the FLOW-3D simulation results and the physical model. The comparison showed the results to be consistent and the FLOW-3D simulation accurate.

Keywords


FLOW 3D, Erosion, Inclined Bridge Pier, Simulation

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References


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