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Say I have a fluid model, with initial pressures, temperatures, valve settings, etc.

Is there a way to run a State Graph simulation where each of the states contains new component parameter settings for the model, i.e. some parameters of some selected components are changed during one state, and are changed again during the next state?

For example, during State1 let's set the values for the following component parameters:

  • source.pressure = 1
  • source.temperature = 1
  • valve1.opening = 1

Until State1 switches to State2 where the parameters are:

  • source.pressure = 0.5
  • source.temperature = 0.5
  • valve1.opening = 0.5

Thanks for your time :-)

Russ D.
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1 Answers1

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Short answer: No. For that use-case you should use discrete variables (and change them using a when-clause).

Long answer: As of version 3.3, Modelica has a new feature, called State Machines (see chapter 17 of the specification). In theory, it should do what you require, but it might still be buggy since it is quite new.

What you are attempting to do is called "variable structure modeling" (although only changing parameters is hardly "variable structure" and can be implemented using discrete variables instead, as my short answer suggests). Long before StateMachines where introduced to Modelica, this was (and remains) an active area of research. You could also use an external tool to achieve your goal, e.g. DysMo

choeger
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