Investigation on the scouring and protecting of downstream of hydraulic structure in river Mahshad

The effect of scour on water structures, including bridges, is an important topic in civil engineering and river engineering. Bridges are among the oldest engineering structures. One of the most important factors in the destruction of bridges is the problem of local scour around their piers. This type of erosion can be identified by a hole that forms around the structure. If this hole expands in depth, it can cause damage and ultimately collapse of the bridge. To accurately examine the flow and predict local scour around bridge piers, it is necessary to accurately understand the flow pattern around the piers. With a complete understanding of the flow, the flow field can be completely modeled by solving the governing equations and, together with solving the sediment transport equations and relying on significant advances in computational fluid dynamics (CFD), an accurate method for estimating local scour around these structures can be obtained. In the present study, a simulation was performed using Flow-۳D software, which is a powerful software for simulating flow turbulence in three dimensions. For this purpose, using the Shallow water model, the flow characteristics including water level, velocity, pressure, etc. were calculated due to the passage of a discharge with a hundred-year return period (m^۳/s ۲۷۲۳) in the area from the beginning of the first bridge to ۱۰۰ meters downstream of the second bridge. Then, using the Sediment scour model, the extent of the development of the scour process around the bridge piers was examined in ۳D. The results show that the most scour occurs in the third, fourth, and fifth piers.

کلیدواژه ها:

Local scour ، computational fluid dynamics ، Flow-۳D model