Seabed contact takes account of the line contact diameter. The Anchored option gives access to an additional data item called ‘Height above seabed’ which is important to get the correct seabed interaction at that connection. The Connection table shows End A is attached to the vessel ‘FPSO’ and End B is Anchored. The lower is a range graph of normal drag coefficient along the catenary length.īuilding the model Open the model browser via the Model dropdown menu (or use the shortcut F6) then double click on ‘Catenary Hose’ to open its Line Data Form. The upper graph is of top connection End Force against End Force Ez-Angle. When you open the simulation file you will see side elevation views of the catenary in both wireframe and shaded format. The example has a single riser in a simple catenary extending from a vessel to the seabed.
Production Risers: A01 Catenary and Wave Systems
This is sufficient for most systems of this type to achieve a settled response. The main analysis (Stage 1) is given a duration of five wave cycles. Less than this and the rapid application of the wave could generate unwanted transient loads. The build up (Stage 0), where wave heights are ramped up from zero to the required value, is given a duration of one wave cycle. The Dean Stream non-linear wave theory has been applied because it is accurate over a wide range of water depths. These are repeated waves with the same height and period. Modelling tethers and their clamps.Īll the examples in this set have regular waves applied. Variation of drag coefficient with Reynolds Number. On opening each simulation file, the default Workspace will present wireframe and shaded graphics views of the system. These are a simple catenary, a lazy wave, a steep wave and a pliant wave. A01 Catenary and Wave Systems Introduction In these examples, four types of riser system are shown.