# Questions tagged [openmodelica]

OpenModelica is an open-source implementation for the Modelica modeling language.

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5 votes
2 answers
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### Recommended language/environment for large scale semi-continuous biological models

We have a fairly large (maybe 1000 equations) differential-algebraic equation model written in ACSLX, an obsolete modelling environment similar to Modelica. The model represents the evolution of a ...
0 votes
1 answer
391 views

### Modelica and SIMULINK yield completely different results

I'm trying to simulate a 1D model of two bodies sliding on each other with a Coulomb friction in between. As I have explained here I modeled the friction as : The force required to keep two bodies ...
• 147
2 votes
1 answer
286 views

### Finite difference method not working for advection PDE with negative coefficient

I'm trying to solve a very simple advection PDE $\frac{\partial u}{\partial t}+c\frac{\partial u}{\partial x}=0$ where $c<0$. I have been able to implement a simple Modelica code to solve the ...
• 147
1 vote
0 answers
70 views

### Object-oriented non-linear solving in python

I'd like to build a system in Python, consisting of (broadly speaking) objects which are internally described with (not necessarily just linear) equations, that I can connect with each other - similar ...
• 245
14 votes
3 answers
18k views

### Alternatives to Comsol Multiphysics

This might be a question better suited for the Software Recommendations side of S.E., however I do believe that people who frequent this part of S.E. are more likely to be able to answer this question....
• 255
2 votes
1 answer
485 views

### Modelica "derivative" annotation problem

I have questions about the use of "derivative" annotation I wanted to ask you. Lets put a sample. The equation is this: z_level = LevelZ(time); where LevelZ(...
• 95
1 vote
0 answers
287 views

### How to do something in Modelica every solver iteration?

How is it possible to do something once every solver iteration? The expressions when change(time) or when time > pre(time) ...
• 95
6 votes
1 answer
5k views

### How to do co-simulation with two FMU models

I have two FMU developed with different simulation tools. I would like to connect them through some variables and run a co-simulation with an open source tool as OpenModelica. This co-simulation has ...
• 95