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Avoid problems with Fluid library in System Modeler 5?

Posted 4 years ago
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I'm happy to see version 5 now supports the Media library. Is there some reason the Fluid library is not supported?

I of course tried 3.2.2 Fluid library from modelica.org with mixed results.

It would be helpful if I knew what it is about the Fluid library System Modeler 5 has trouble with and when you plan to support it.

Thanks.

8 Replies

Hi Eric,

I am glad support for the Media library is useful for you. Currently, two specialized features used in the Fluid library is not fully supported: homotopy-based initialization and stream connectors.

We are aware that the Fluid library is sought after by many users and the development team is hard at work with including support for this. Though I cannot give you any exact dates, it is a high priority and we hope to see the library supported in the near future.

Posted 3 years ago

Thanks Patrik. That's helpful. I've been holding out since I really need stream connectors. Glad to hear you're working on it.

Is there a stable earlier release for the Fluid library that can be used? (After all, the problem persists as the Fluid library is not included in Version 12)

Stream connectors afaik have been introduced in 2009 (Version 3.1) only - and before that there seems to have been a stable version:

https://modelica.org/events/modelica2006/Proceedings/sessions/Session6b1.pdf

The FluidPort connector referenced in the paper above does not have stream connectors.

Hi Guido,

Since we do not have full support for fluid library yet, we have not tested with earlier releases of Modelica. So I am not sure whether it will work or not.

Regarding the fluid library, we have been making good progress. We think we have fixed the homotopy initialization issue and working on fixing other issues for a stable release.

Regards, Ankit

Hi Ankit,

Thanks for the clarification.

So, while the MFL is not being supported, I am curious: Would working with an imported FMU work out in System Modeler (cf. System Modeler Documentation: FMI - Using an Imported FMU)? As a preliminary workaround: OpenModelica does support the MFL and I assume that working with the FMU essentially is wrapping interfaces around C code?

Can Mathematica work with imported FMU (i.e. make fully use of the FMI) or is that restricted to System Modeler interaction? (The documentation suggests that currently only Export is supported)

Regards,

Guido

Hi Guido,

You are right, importing the model as FMU will work. I tested some FMUs of simple models from OpenModelica (from electrical and fluid domain) and it works. You will, however, need to to create real inputs and outputs to modify or access the values of variables.

You will need SystemModeler to open the FMU, you cannot import FMU in Mathematica as of now.

Regards, Ankit

Great news! Thank you for that quick response, Ankit.

You will need SystemModeler to open the FMU, you cannot import FMU in Mathematica as of now.

But I assume, that once imported (with input/output wrappers) into System Modeler one could run the model using Mathematica as usual?

Thanks,

Guido

Yes, once imported you can use it as a normal model.

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