Large eddy simulations and analyses for bridge scour development

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Hayder Majeed, Nigel Wright, Andrew Sleigh

Tuesday 30 june 2015

17:57 - 18:00h at Europe 1 & 2 (level 0)

Themes: (T) Water engineering, (ST) Computational methods, Poster pitches

Parallel session: Poster pitches: 7E. Engineering - Computional

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Bridge scour has been identified the main cause of bridge failures. The loss of soil around bridge pier may leave the bridge with inadequate support and consequent complete failure of the bridge may occur. In this study the complicated three dimensional scour patterns around bridge piers will be described numerically based on computational fluid dynamics (CFD) using large eddy simulation (LES) to simulate the flow field around the bridge pier and calculate the shear stress which will be considered the key parameter to control on the sediment motion in scour process. Then a moving mesh technique will be used to simulate accurately the change in the river bed at each time step. A user-defined function in the CFD software will be used to compare the shear stress calculated from large eddy simulation with the critical shear stress which initiates sediment transportation. Once the critical shear stress is exceeded, the movable sediment near to the pier will immediately happen. The influence of pier shape and the angle of attack of the flow around the bridge pier on the scour behavior are the main parameters considered in this study. Keywords: Large eddy simulation (LES); bridge pier scour; moving mesh technique; critical shear stress; user defined function (UDF).