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QBlade ForumQBlade: Simulation Setup and EvaluationMulti rotor : Fixed floating plat …

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Multi rotor : Fixed floating platform or onshore platform

#1 · 12. September 2023, 16:55

Dear all,

I wish to create a multi rotor assembly, at the moment it doesn’t matter if it is onshore or offshore.

I used the Volturn_US floater and managed to stick on it the rotors I wanted. However, the floater is not meant for that tilts and sink after some time. I tried the floating true/false option and set the depth to 0m but to no avail…

Is there a way to “freeze” the floater or to define an onshore platform for multi rotor ?

Thanks,

Thomas

#2 · 13. September 2023, 11:26

Hello Thomas,

to fix a floating platform you can simply connect any of the platform joints, or the transition piece, to the ground via the SUBCONSTRAINTS table.

Alternatively, you could also use one of the bottom fixed examples, such as the IEA 15MW Monopile, as a starting point.

If you would like to define an onshore multi-rotor turbine you simply have to set the WATERDEPTH variable to zero and the ISFLOATING variable to false. In this way the substructure file can be used to define an onshore turbine.

BR,

David

#3 · 13. September 2023, 14:44

Dear David,

Thanks for your answer, I was able to do what I wanted.

Now, upon looking at the results, it appears that the platform doesn’t produce wake ? Since I am modeling a VAWT, I am using the FVW option. I can clearly see the wake evolving behind the rotors, but they do not seem to interact with the support platform. Is there an additional option to activate ?

Thanks,

Best regards,

Thomas

#4 · 13. September 2023, 15:37

Hi Thomas,

only the wake generated by the rotor and the struts is modeled in QBlade.

The interaction between the wake and the support structure cannot be accounted for with the LLFVW approach. For this a full CFD model would be required.

Beat regards,

David

ThomasPotentier has reacted to this post.

#5 · 13. September 2023, 15:47

Thanks for the clarification !

Thomas