Studying interactions between mean flow fields around a submerged bridge deck, channel bed and free surface

During a critical river flood event, a bridge deck may become partially or completely submerged by the flow. The deck submergence may be a critical situation for structural stability of river bridges. In this paper, the mean flow fields around a submerged bridge deck and the time averaged drag coefficient on it have been simulated by using Fluent software. The turbulence models considered are the standard, renormalization group (RNG) and Realizable. In these simulations for a fixed water depth on a deck, the effect of change of deck distance from the channel bed on the mean flow field around a deck and the time averaged drag coefficient on it, have been investigated. In these simulations, for a water depth constant in the deck upstream, the effect of change of deck distance from the channel bed, and water free surface on the mean flow field around a deck and the time averaged drag coefficient on it have been investigated. For the deck located near the channel bed (the deck distance from the bed equal to 0.5 times the thickness of the deck), Simulation results of RNG and Realizable turbulence models are in better agreement with experimental results. In other distances from the channel bed, standard turbulence model provides better accuracy. If the deck distance from the channel bed and free surface is significant