Numerical Investigation of the Erodible Bed Changes Around the Submerged Pipeline affected by the Protective Plate

Scouring at the place of submerged pipelines under the effect of eddy currents around the pipe passing through the riverbed leads to the settlement and failure of the pipeline as well as the penetration of the fluid passing through the pipe into the stream. Therefore, efforts to reduce these risks and their effects are always the attention of researchers and engineers. In the current research, scouring and sedimentation around the pipe and its surrounding bed under the effect of a protective plate at different positions and heights have been investigated and analyzed using Flow-3D. A comparison of the simulation results of the present research with the laboratory results showed that the used numerical model with the statistical index R2=0.96 has an acceptable ability in simulating the mentioned phenomenon. Also, the results showed that by installing a plate with a height of H=1.25D (D is the diameter of the pipe) and at a distance of 0.5D downstream of the pipe, the scouring depth under the pipe decreases by 60%, and also the average level of the bed in the upstream area increases by 82%, which is the most optimal state among different downstream positions. The optimal state of the plate in the upstream corresponds to the height of H=0.75D and at a distance of 1.5D, which not create scouring, and the average level of the bed between the pipe and the plate in the upstream has increased 4.9 times compared to the state without the plate.