<< Click to Display Table of Contents >> Navigation:  Flexcom > User Interface > Flexcom Wave > Project View > Simulations > Simulation Parameters >
Seastate Blocks and Reference Seastates

 

Flexcom Wave allows you to estimate simulation results for seastate combinations which you have not actually simulated. Based on some selected 'reference seastates' in your scatter diagram, the software estimates results for adjacent seastates based on an extrapolation technique. The simulation of an entire scatter diagram in the time domain can be quite time consuming, so this is a highly efficient solution technique which can save you considerable computational time. However given the inherent approximation involved, caution is strongly advised regarding the application of this feature.

This 'reference seastate' method can certainly be used during preliminary feasibility studies, and also during initial screening processes which consider various types of wave energy converter in a particular location. For computational efficiency, it may also be useful while you are fine-tuning a chosen device to suit the ambient environment. However once you are reasonably satisfied with a particular design configuration, it is strongly recommended that you explicitly simulate all seastate combinations in the scatter diagram. This will provide the most accurate estimate of a device's operational performance. A related benefit is that it will also allow you to quantify any inaccuracies associated with the 'reference seastate' method.

Within the Scatter Diagram itself...

•The Mark Seastate Blocks feature is used to group similar seastates into blocks. This task can be performed at any stage during the input of the scatter diagram data, but would typically be performed after all of the Hs and Tz/Tp/Te data has been input. You may also delete blocks subsequently, allowing you to change the way in which seastates are grouped in blocks without inputting the scatter diagram again in full.

•The Mark Reference Seastates feature is used to nominate reference seastates within each block. This task can only be performed after one or more seastate blocks have been defined. If you click on a seastate in a block where a reference seastate is already nominated, the previous nomination becomes deselected.

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, any 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 at smaller wave amplitudes the extrapolation technique is likely to be more accurate.