Vessel and RAO Data |
 
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Vessel and RAO Data |
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Two sets of inputs are required to completely define the response of a floating vessel to the ambient wave field. The first set defines the vessel initial position, that is, the location of the vessel prior to the application of any vessel offset or dynamic motions. This information is defined in terms of the location of the vessel reference point (the point at which the RAOs are defined), and initial yaw orientation of the vessel.
The second set of inputs is the full vessel RAOs and phase angles in all vessel degrees of freedom. Given the vessel’s initial position, offset and RAOs, in addition to the time history of wave elevation, the motion of the reference point in response to the wave field throughout an analysis can be calculated, and from this the motion of the point(s) on the structure attached to the vessel. As the RAO data may be quite extensive, it is typically stored in a separate file which is simply referenced by the main keyword file. The file with RAO data already exists in the Worked Example - Basic folder, and is named K1-SWR-RAO.incx. This should be copied into the folder for this project. Refer to High Frequency RAO Motions for further information on this feature.
You may also optionally associate a structural profile with the vessel. While this does not affect analysis results, it does add considerably to the visual appeal of the structural animation. A range of standard vessel profiles are provided; the FPSO profile being particularly suited to this worked example.
The vessel in this model is located at X=305m, Y=120m, Z=0m and has an initial yaw orientation of 50 degrees with respect to the global Y-axis. The completed specification of vessel data for the FPSO in this example is specified as shown in the figure below. Note that all vessel data (apart from vessel offsets) is specified in the $MODEL section of the file.
Vessel Data
Refer to *VESSEL INTEGRATED for further information on these data inputs.