Author(s): Mohammad Reza Hadian; Amir Reza Zarrati

Linked Author(s): Amir Reza Zarrati, Mohammad Reza Hadian

Keywords: Fflux; Bridge constriction; Shallow water; Numerical model; Depth averaged

Abstract: Calculation of afflux and backwater at bridge constrictions is one of the most important factors which should be considered in hydraulic design of bridges over rivers. The 2D depth averaged form of shallow water equations is employed in the present study to calculate backwater upstream of a constriction. The equations are solved on unstructured blocks with structured grids used in each block. The model uses collocated grid arrangement and SIMPLEC like algorithm for velocity-water surface coupling. As a benchmark, a bridge constriction was simulated in a laboratory flume and was tested for common range of Froude numbers in engineering projects. The water surface profiles were measured at center line of the channel and some cross sections upstream of the constriction and were compared with the results of the numerical model. The comparison showed that both zero equation and k-ε turbulence models which are implemented in the numerical model give accurate results in all Froude numbers tested. It is also shown that the numerical model is more accurate than the empirical method used even though the tests were conducted in a simple straight channel with vertical abutments.

DOI:

Year: 2007