WECCCOMP – Forums WECCCOMP forum A few questions regarding the Evaluation metric and the wave probes

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  • #1348

    Hi,

    We have a few questions which we were hoping you provide some clarification:

    1. How long will the simulations be in the evaluation and what portion of the signal is used to evaluate the metric? Currently in the code the simulation length is set to 25 x 1.412s (in wecSimInputFile.m), and then the portion of the signal used for evaluation is from 25s to the end (in userDefinedFunctions.m). Are these the official values that will be used?

    2. The EWTEC paper and website states the performance metric will be evaluated with respect to 95th percentiles, but then the pdf info sheet on the website, states 98th percentile?Just wondering that is the official values that will be used.

    3. The metric in the pdf info sheet requires F_max and Z_max, the constraints on the PTO force and displacement. The EWTEC paper states the Pto force constraint to be 60N. What is the displacement constraint?

    4. Where the metric in the pdf info sheet mentions electric power, is this the power multiplied by the efficiency? If so, is the efficiency value of 0.7, currently in userDefinedFunctions.m, the official efficiency that will be used?

    5.Also, in the metric in the pdf info sheet, avg(p) and avg|p| reference the electrical power, but |p|98 doesn’t. Does |p|98 refer to the electrical power as well or the absorbed power?

    6. The EWTEC paper and the website state the free surface elevation will be given at 3 points up-wave from the device. In the code there is one wave gauge at position 0.1m. Just wondering whether it will be three or one, and what are the locations?

    Thanks,

    BME Team

    #1350
    Tom Nathan
    Organiser

    BME Team,
    Thank you for your questions, the WECCCOMP organizer responses can be found below:

    1. Each WEC-Sim simulation should have a ramp time of 5*Tp and a simulation end time of 100*Tp.
    The first 25 seconds of the WEC-Sim simulation will be discarded for calculation of the
    competition metrics (the evaluation criteria will only be calculated for time > 25 s). The
    WECCCOMP WEC-Sim info sheet has been updated with this text.

    2. The organizers apologize for the confusion. The evaluation criteria will be based on the 98th
    percentile as written on the WECCCOMP-info-sheet. We will update the website.

    3. The displacement constraint, Z_{max}, has been set at 0.06 m (6 cm) and the WECCCOMP-info-
    sheet has been updated for clarity.

    4. Yes, the linear motor efficiency has been set at 70%. The efficiency value has been added to
    the WECCCOMP-info-sheet and includes the equation on how the piece-wise calculation for
    generator/motor power is calculated

    5. The |P|_{98} percentile does refer to the electrical power. The WECCCOMP-info-sheet has been
    updated for clarity.

    6. WEC-Sim currently has one wave gauge that can be placed anywhere along the x-axis by using the
    waves.waveAmpTimex option in WEC-Sim. Two more wave gauges will be added to WEC-Sim once we
    have confirmed with AAU on the wave probe location for the experimental portion. This will be
    updated in the WEC-Sim code early next week.

    Again, thank you for your comments! If you have additional questions or want further clarification please leave a comment on the forum and the organizing team will respond as soon as possible.

    Cheers,
    Nathan Tom
    National Renewable Energy Laboratory

    #1351

    Thanks very much Nathan

    #1352
    Tom Nathan
    Organiser

    BME Team,
    The WECCCOMP organizers wanted to update you on point 6 from your initial questions.

    6. WEC-Sim has been updated so there are three wave gauges available for competitors to use. The location and details of the implementation can be found in the WECCCOMP_WECSIM_info_sheet_v7.pdf that has been uploaded to the WECCCOMP GitHub site. Please pull the latest version of WEC-Sim and the WECCCOMP folders.

    Again, thank you for your comments! If you have additional questions or want further clarification please leave a comment on the forum and the organizing team will respond as soon as possible.

    Cheers,
    Nathan Tom
    National Renewable Energy Laboratory

    #1355

    Hi Nathan,

    I might be mistaken, but I think that the new advanced feature providing up to three numerical wave gauges has not been included in the master branch of WEC-Sim. It follows that the latest version of WECCCOMP cannot run (as the new property ‘waves.wavegauge<i>loc’ is unknown). The new feature is included in the ‘gh-pages’ branch, though.

    Cheers,

    Paolino Tona
    IFPEN Team

    #1364
    Tom Nathan
    Organiser

    Paolino Tona,
    Thank you for notifying us of that version issue. We have just pushed the changes to the GitHub Wec-Sim repository. You should now be able to use the additional wave gauges “waves.wavegauge<i>loc.” Please let us know if you have any further issues.

    Cheers,
    Nathan Tom
    National Renewable Energy Laboratory

    #1366
    Tom Nathan
    Organiser

    BME,
    After some discussion between the WECCCOMP organizers, we have decided to increase the maximum allowable motor linear displacement.

    1. The value for Z_{max} is now 0.08 m (8 cm), please use this value for calculating the evaluation
    criteria. The WECCCOMP-info-sheet_V6.pdf has been updated for clarity.

    Apologies for any confusion this has caused. If you require additional clarification, please post to the forum and the organizers will respond as quickly as possible.

    Cheers,
    Nathan Tom
    National Renewable Energy Laboratory

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