User Operation |
 
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User Operation |
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Using the Summary Wave Scatter feature is quite straightforward, you simply follow a logical sequence of steps. The following instructions should serve as a helpful reference guide.
•Obtain metocean data for your geographical location of interest. Depending on your data source, the data may be readily transferred into a spreadsheet for ease of inspection.
•Create a new Flexcom keyword file and insert a new $Summary WAVE SCATTER section. The Summary Wave Scatter feature requires access to many input and output files, so this keyword file is typically placed in the top/root level of your project folder.
•Define the wave scatter diagram in Flexcom. When transferring the metocean data from Excel into Flexcom, the quickest way is to use the Scatter Diagram table - this will allow you to copy and paste directly from Excel, and is more efficient than working with *SCATTER DIAGRAM in the keyword editor.
•Note that the wave spectrum used in the definition of the scatter diagram must be either Pierson-Moskowitz or Jonswap. Use the *WAVE SPECTRUM keyword to inform Flexcom which spectrum type you are using, and also whether your wave periods are defined in terms of Tz or Tp or Te.
•Use the Scatter Diagram table to group similar seastates into blocks and to nominate a reference seastate to represent each block. Some caution is advised regarding the number and selection of reference seastates which are chosen to approximately represent the full scatter diagram. This will require engineering judgment on your part, but the following general advice may be helpful.
•Generally speaking, an inaccuracies associated with the extrapolation process are likely to be more pronounced across different wave periods rather than wave amplitudes. Hence it is not advisable to have blocks which span more than two different values of Tz/Tp/Te.
•Structural responses at smaller wave amplitudes tend to be more linear than responses at higher amplitudes, so the extrapolation technique is likely to be more accurate.
•Create Flexcom keyword files to perform time domain simulations for each reference seastate. It may be helpful to create a single master template input file which will automatically generate all the required input files to simulate each seastate. Use the *PARAMETERS keyword to create variables to represent Hs and Tz/Tp/Te. Then you can use either *VARIATION or *EXCEL VARIATIONS to define the various combinations of Hs and Tz/Tp/Te which you wish to consider (i.e. the reference seastates).
•Add a $DATABASE POSTPROCESSING section to the master template file and use the *TIMETRACE keyword to request the creation of time history plots of pertinent output variables. Nomination of these parameters is essential as the Summary Wave Scatter feature will use the plot files created by Flexcom for the reference simulations in order to generate Summary Database Files for all the non-reference seastates in the wave scatter diagram. Refer to Extrapolation Technique for further information.
•Run the time domain simulations and associated postprocessing for the reference seastates.
•Run the Summary Wave Scatter feature. This will generate Summary Database Files for all the seastates in the wave scatter diagram.
•Create a new Flexcom keyword file and insert a new $SUMMARY COLLATE section. The Summary Collation feature requires access to many input and output files, so this keyword file is typically placed in the top/root level of your project folder. Use the *IDENTIFY keyword to nominate the sub-folders of interest within your project workspace. Use the *PLOT keyword to request the creation of 3D plots as a function of Hs and Tz/Tp/Te. Ensure that the Figure Titles that you specified in the *TIMETRACE keyword of the $DATABASE POSTPROCESSING section are consistent with the Output Title that you specify in the *PLOT keyword.
•Run the Summary Postprocessing Collation and examine the newly created Summary Collation Plots. Note that the Summary Collation Spreadsheet provides a tabular representation of the same data also.