Comparison of Turbulence Models for Simulation of flow Around the Submerged Bridge Decks

During a critical river flood event, a bridge deck may become partially or completely submerged bythe flow. The deck submergence may be a critical condition for structural stability of river bridges. Inthis paper, the mean flow fields around a submerged bridge deck and the time averaged dragcoefficient on it have been simulated by using FLUENT software. The turbulence models consideredare the standard k 
, renormalization group (RNG) k 
and Realizable k 
. In these simulations,the VOF and rigid lid methods have been used for free surface simulation. Reconstruction and Finitevolume schemes have been used to determine the position of the free surface in VOF method and theresults have been compared. Simulation results of time averaged drag coefficient show that in the caseof partially submerged deck, Geometric Reconstruction Scheme in VOF method with standardturbulence model is in better agreement with the experimental results. In the case of fully submergeddeck, RNG k 
and Realizable k 
turbulence models provide better accuracy than standardturbulence model. Also, simulation results show that Reconstruction based schemes in VOFmethod are not capable to simulate mixing of water and air and finite volume schemes have to be usedfor mixing of water and air simulation.