- the spring constraint is currently unused but it can be used for Elmer mechanical analyses
This PR does so and also overhaul the dialog UI.
- use the spring constraint also in an example file
- use a more sensible velocity distribution
- change inlet temperature for 2 examples
- also change step size for nonlinear iterations for more convenience for practical usage
- same as #8963 but for initial velocity
- add an example file that demonstrates the influence of the initial velocity
- some fine-tuning for the existing flow example
- complete revision of the constraint.
This is a breaking change, meaning existing constraints won't work.
This is possible because since 2 days ago the whole flow equation did not work at all. Also the existing constraint implementation if buggy and cannot be used to do the Elmer tutorial. Also, the constraint is only used by Elmer and only be the flow equation.
Since nobody complained about the obvious wrong results, we can assume the flow equation was not yet in practical usage (and for FC 0.20 we known that it does not work at all, first with FC 0.20.1).
It is necessary since it must be possible to either input a velocity or an equation. With an equation, a velocity profile can be specified.
- update the flow examples accordingly:
-- simplify them since an initial and and output velocity is not necessary to specify
-- use a formula as input velocity for the non-turbulent example
- the heat capacity of water was wrong
- also specify just thermal expansion, this make that water is recognized as material and then all water parameters will be available
(that the analysis fail despite CalculiX reports everything went well s is another issue, I will investigate later)
- define materials so that they are recognized by material handling as existing card
- use "electrodynamics" as equation because this is the common name for the physics of these examples
- fix typos
- active already the analysis
- generate the mesh preferably directly, also if this fails, load the rough meshes
- use value for Air is they are in our Air material card
- apply material to the body (not necessary but good practice, the examples are there to teach people and for more complex models setting the material to a body is important)
- (a regression to FC 0.20.0), use new settings ("direct" is already the default, iterative solving takes here about 5 times longer, DisplaceMesh must be False)
String List instead of String should allow for arbitrarily many entries,
theoretically.
Note the defaults previously in `YieldPoint1` an `YieldPoint2` were arbitrary.
Now the list is kept empty by default.
Fixes issue #4720.
