Mojtaba damroudi - Director of Design Department consulting engineering of haft pargar sayal jam, Bojnourd, Iran
Kazem Esmaili - Department of water science and Engineering, Ferdowsi university of mashhad, Iran
Seyyd Hossein Rajaei - Researcher at Khorasan Razavi Agriculture, Natural Resources Research and Education, Iran
Majid Vahdani Asadi - Water resources development expert of Water and Sewerage Company, Bojnourd, Iran

Offshore pipelines are buried in the seabed to be protected from the damage caused by hydrodynamic forces or by human activities. However, because of soil erosion and interaction of currents with the pipeline on the moveable seabed, the processes of local scouring and, sometimes, self-burial of pipelines take place. To increase the rate and extent of scouring, the technique of attaching a spoiler to the pipeline has been developed. through the parameters of the measured instantaneous and time-averaged patterns of the velocity vector field and the streamline topology. In this study, the effect of the spoiler on the process of scouring is investigated. The results indicated that the attachment of the spoiler to the pipeline increases the length of the upstream and downstream scour hole. Moreover, on average, increased the scour depth of the pipe up to 62% rather than simple pipe.

Local Scour, Pipeline, Spoiler, Offshore, River