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MoorDyn #2270

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WS991106 opened this issue Jun 18, 2024 · 8 comments
Open

MoorDyn #2270

WS991106 opened this issue Jun 18, 2024 · 8 comments

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@WS991106
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Dear @andrew-platt

I don't really understand what 1,2,3,4 means under this channel and line, can you please introduce it?
https://forums.nrel.gov/t/moordyn-line-segment-minimum-length/3556/4

Best regards,

@andrew-platt
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The documentation on this is a bit limited at present: https://moordyn.readthedocs.io/en/latest/inputs.html#control-moordyn-f-only

This input section specifies which lines are assigned to which control channel in the ServoDyn input file. In the example linked above,

---------------------- CONTROL ----------------------
ChannelID Line(s)
()       (,)
1       1,2,3,4
2       5
  • channel 1 is used to control lines 1, 2, 3, and 4
  • channel 2 is used to control line 5

These channel numbers must correspond to control channels in the ServoDyn input file. The ServoDyn summary file (enable with SumPrint option) will contain a list of all cable control channels in use and what they are assigned to.

@RyanDavies19
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@andrew-platt Thanks for that succinct explanation, I am adding it to the MD docs

@WS991106
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Dear @andrew-platt

You say here that the DeltaL instruction is to control the length of the last section of the mooring line, but I found that there are 20 instructions in simulink, I would like to ask if it is now possible to give DeltaL instructions for each section of the mooring line?#565
image

Best Regards,

@WS991106
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The documentation on this is a bit limited at present: https://moordyn.readthedocs.io/en/latest/inputs.html#control-moordyn-f-only

This input section specifies which lines are assigned to which control channel in the ServoDyn input file. In the example linked above,

---------------------- CONTROL ----------------------
ChannelID Line(s)
()       (,)
1       1,2,3,4
2       5
  • channel 1 is used to control lines 1, 2, 3, and 4
  • channel 2 is used to control line 5

These channel numbers must correspond to control channels in the ServoDyn input file. The ServoDyn summary file (enable with SumPrint option) will contain a list of all cable control channels in use and what they are assigned to.

Wouldn't "5MW_OC4Semi_WSt_WavesWN" just need one channel to control all three lines if it only sets up three mooring lines?

@WS991106
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I'm wondering if channel 1 can control lines 1, 2, 3, and 4, is it similar to going to a unified paddle for unified control? And how do I modify it if I want to control all three lines individually?

@andrew-platt
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There are up to 20 channels available for controlling lines from both MoorDyn and SubDyn. You may use each of these channels to control one or more cables. So for a turbine model with 3 mooring lines, you can control each of the lines separately as follows:

---------------------- CONTROL ----------------------
ChannelID Line(s)
()       (,)
1       1
2       2
3       3

or all lines together as follows:

---------------------- CONTROL ----------------------
ChannelID Line(s)
()       (,)
1       1,2,3

In MoorDyn, the line actuation is only on the last segment.

@WS991106
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Author

@andrew-platt Thank you for your answer, I understand. I would also like to ask if there is any literature I can refer to when I want to implement control over the length of the last paragraph? Because I'm not quite sure how to set up the controller.

@andrew-platt
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Unfortunately I do not know of any publicly available literature or modeling cases using this feature. This is likely be something that you will need to develop in your controller for your specific use case.

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