Investigation of temporal scour development below submerged pipe under the wave effect

Due to the recent technologic development, submerged pipelines are the most frequently used structures in coastal engineering applications. They are in use in marine outfall systems, oil and gas transportation, submarine cable conduit, as well; accordingly, to maintain their strength and stability, during their economic life, is crucial. In marine environment, dynamic and repetitive effects that affect the lateral stability of submerged pipelines are mainly originated from steady flow and wave motion. The flows with the effect of steady current around a submerged pipeline and scour in erodible soils have been a research subject for many researchers and engineers. However, the studies under the condition of wave effects are limited. Moreover, the major parts of this investigation are the studies that focus on the final scour depth. In the scope of this thesis, temporal variation of scour around submerged pipelines was investigated. Besides, the scour development along the pipeline and the progression of the free-span were examined. In order to better understand the phenomenon of scour below submerged pipeline, many experiments were carried out with different wave characteristics, pipe diameters, bed materials and initial forms for bed condition. The results obtained from these experiments were analyzed under the titles entitled ?final scour depth?, ?time scale?, ?time-dependent scour depth? and ?scour development along the pipeline?. The obtained results were visually represented by generating diagrams that will help for applications. Also, a two-dimensional numeric model reflecting experimental conditions was generated by using Flow 3D, and the findings were evaluated comparing with the experimental results. Keywords: Submerged pipe, wave effects, scour, time dependent scour depth