Fluid-pipeline-soil interaction at the seabed

In this thesis, two particular pipeline design issues on the fluid-structure-soil interaction spectrum are considered : (i) the on­ bottom stability and safe operation of subsea pipelines and cables, and (ii) predicting seabed trenching within the touchdown zone of risers connected to floating vessels. The first three chapters focus on pipeline-soil interaction with regard to the soil resistance available to prevent pipeline movement in various scenarios. The following two chapters explore the fluid mechanics around an oscillating two-dimensional cylinder representative of a riser near the seabed. In the final chapter, an experimental study on trenching beneath an oscillating cylinder is presented.