Numerical Simulation Of Pier Localized Scour Of Pier Under Protection Of Tetrahedron-like Penetrating Frame Group

For alluvial river, water damage, especially local scour of bridge piers are almost inevitable. Local scour, cut of river bed around the pier, is in theory caused by three-dimensional boundary layer separation generated by high intensity of flow turbulence and vortex system, which can affect the stability of piers. Some protection engineering projects must be installed to guarantee the river bed around the pier in the design of bridge piers. So far the local scour protection engineering mainly focuses on protecting the river bed around pier from being washed, protecting the bridges from being ruined by water.The measures adopted currently to prevent the piers from being washed locally have many disadvantages which can even be causes of the big-scale failure of protection projects. The tetrahedron-like penetrating frame group helps to solve this problem to certain extent and is widely used as a novel way to waive scour. The development in computational fluid mechanics and computer technology has provided great opportunity for reproducing complex turbulent flow and this solution has been recognized by industry. Simulation of pier local scour done by computational fluid mechanics will be different from traditional ways.This paper investigates the mechanism of water damage to bridges and analyzes the forming process of local scour from fluid structure. With the controlling equations and closing method, also the separation and boundary controlling methods, simulation mainly focuses on two aspects:(1) Scour analysis of single one pier. Three-dimensional models are established with tetrahedron-like penetrating frame group surrounding single one pier. The model adopts non-structuralized meshing method in Fluent to analyze water flow and flow structure. The analysis mainly focuses on the influence by tetrahedron-like penetrating frame group to water flow and flow structure.(2) Scour analysis of group piers. The simulation is based on the actual design of Baoxi Railway Bridge with same geometry size. Same tetrahedron-like penetrating frame group will be applied and analysis starts with effect on flow speed by such protection method. Some suggestions are proposed based on the theory discussion of penetrating frame group and engineering experience.