The Research Of Numerical Simulation On Local Scour At Bridge Piers

The local scour that occurs around a bridge pier founded in erodible bed materialis a complex three-dimensional phenomenon. Accurate analysis and forecasting arestill some difficulties on the pier local scour at present. The depth and scope of localscour at pier of bridge are very critical parameters during the bridge design. A lot ofdomestic and international scholar and Scientists and Technologists have carried outplenty of research about the pier local scour, such as prototype measurement, indoormodel test and numerical simulation. They have put forward a lot of empirical andsemi-empirical formula, which are very significant to the research of the pier localscour. Numerical simulation of its unique advantages will play a vital role in thefuture research of pier local scour with the development of computer hardware andCFD.The three-dimensional numerical simulation of two-phase current with a singlecylindrical pier has been developed by FLOW-3D. The simulated results arecompared with the physical model test results and it proved that the model is able toperfectly simulate the flow field morphology and scour pit around the pier hydraulicchanges. The numerical simulation can vividly reflect the flow field around bridgepier and the vortex system, and fully show the scoured pit’s forming process. Themain conditions that affect the pier local scour consist of flow conditions near the pier,sediment conditions and bridge pier features conditions. By changing the three factorsof the flow velocity around bridge pier, sediment particle size and pier diameter, thisarticle has simulated the local scour and analyzed the change in the trend of maximumpier scour depth with the three factors. The results which are practical show that themodel can predict the scope and depth of the pier local scour. The results have aguiding role in bridge design, and play an important role in forecasting bed scour andriver flow.