investigation of the flow field around bridge piers on a non-eroding bed using flow-3d

In the present study, the flow field around the bridge piers has been investigated in single pier and pier group modes using flow-3d software. the focus was more on the flow field around the piers in the non-eroding bed state, which actually simulates the flow behavior at the moment before scouring begins. the advantage of the present method compared to the simulation of bed load transfer as well as the tests carried out in the laboratory environment is its short simulation time. two single piers with square and circular cross-sections, as well as a group of double piers with said cross-sections, in tandem and side-by-side arrangements at different distances, have been studied. the results showed that the flow field around the square pier and the cylinder pier were largely similar, which is consistent with the results of other researchers. also, the velocity profiles, turbulent kinetic energy, and shear stresses around the group of piers have been examined, and based on this, suitable distances and arrangements have been presented for the implementation of safe designs. for the group pier with tandem arrangements at close distances (s/d = 2) and for side-by-side arrangements, the limit of distances 2 < s/d < 4 were introduced as critical arrangements. also, the piers in both arrangements are independent at distances s/d > 6 and have no effect on each other.