Add speed of sound property for ThermoPhase

[corykinney]

Changes proposed in this pull request

• Add ThermoPhase::soundVelocity virtual function that returns the equilibrium speed of sound in m/s.
• Add finite difference consistency test c_eq_sqrt_dP_drho_const_s
• Implement definitions for IdealGasPhase, RedlichKwongMFTP, and PengRobinson

Marking this as a draft to see if this would be useful or not. I'm also not sure whether soundVelocity is the best name, I also considered soundSpeed and equilibriumSoundSpeed, or something else could be better. I'm also not certain if ThermoPhase is the best place for it, and I'm not positive I added it to the cython interface properly.

If applicable, provide an example illustrating new features this pull request is introducing

Checklist

• The pull request includes a clear description of this code change
• Commit messages have short titles and reference relevant issues
• Build passes (scons build & scons test) and unit tests address code coverage
• Style & formatting of contributed code follows contributing guidelines
• The pull request is ready for review

[bryanwweber]

I have a preference for equilibriumSoundSpeed and equilibrium_sound_speed for C++ and Python, respectively.

[speth]

Thanks, @corykinney. I think that adding this property is useful, especially when accompanied with implementations for phases other than the ideal gas model, where it's a non-trivial calculation.

I agree that "speed" is preferable to "velocity", but I think calling this the "equilibrium" sound speed would be a misnomer, since the speed is not being computed while holding the mixture at chemical equilibrium. We even have an example illustrating this difference (sound_speed.py).

[corykinney]

Thanks, @corykinney. I think that adding this property is useful, especially when accompanied with implementations for phases other than the ideal gas model, where it's a non-trivial calculation.

I agree that "speed" is preferable to "velocity", but I think calling this the "equilibrium" sound speed would be a misnomer, since the speed is not being computed while holding the mixture at chemical equilibrium. We even have an example illustrating this difference (sound_speed.py).

Yes, frozen was the term I was looking for, not equilibrium. I can rename them to soundSpeed and sound_speed for C++ and Python, respectively.

[ischoegl]

@corykinney ... thanks for the PR. Before a more in-depth review, could you please look into the failing tests? Most likely, you need to (i) add sound_speed to the list of _scalar definitions within the SolutionArray class in composite.py (around line 585), and (ii) add sound_speed to the scalar property _attr list in onedim.py (around line 770).

[codecov]

Codecov Report

Merging #1491 (ecdac2a) into main (5973dbd) will increase coverage by 0.53%.
The diff coverage is 92.30%.

@@            Coverage Diff             @@
##             main    #1491      +/-   ##
==========================================
+ Coverage   69.76%   70.30%   +0.53%     
==========================================
  Files         377      376       -1     
  Lines       58017    58261     +244     
  Branches    20701    20804     +103     
==========================================
+ Hits        40477    40960     +483     
+ Misses      14585    14316     -269     
- Partials     2955     2985      +30     

Impacted Files	Coverage Δ
include/cantera/thermo/IdealGasPhase.h	89.74% <ø> (ø)
include/cantera/thermo/PengRobinson.h	100.00% <ø> (ø)
include/cantera/thermo/RedlichKwongMFTP.h	100.00% <ø> (ø)
interfaces/cython/cantera/composite.py	83.38% <ø> (ø)
interfaces/cython/cantera/onedim.py	83.54% <ø> (ø)
include/cantera/thermo/ThermoPhase.h	46.87% <50.00%> (+0.03%)	⬆️
interfaces/cython/cantera/thermo.pyx	93.18% <100.00%> (+<0.01%)	⬆️
src/thermo/IdealGasPhase.cpp	92.59% <100.00%> (+0.18%)	⬆️
src/thermo/PengRobinson.cpp	84.80% <100.00%> (+0.09%)	⬆️
src/thermo/RedlichKwongMFTP.cpp	84.49% <100.00%> (+0.08%)	⬆️

... and 24 files with indirect coverage changes

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[corykinney]

@corykinney ... thanks for the PR. Before a more in-depth review, could you please look into the failing tests? Most likely, you need to (i) add sound_speed to the list of _scalar definitions within the SolutionArray class in composite.py (around line 585), and (ii) add sound_speed to the scalar property _attr list in onedim.py (around line 770).

Looks like that fixed the failing checks!

[ischoegl]

Hi @corykinney ... thanks for fixing CI - I'm happy that this did the trick! Changes look mostly good to me.

The only other thing I'd ask you to update is the Python example sound_speed.py so it uses the new built-in function for the check with afrozen2. Also, please make sure to update the requires in the header.

[corykinney]

@ischoegl I updated the example as requested (assuming this change will make it into 3.0.0). Also, I saw that there was a sound_speed_units.py example as well, so I believe I implemented the units for sound_speed as required, but I'd like to get a second set of eyes on it.

[ischoegl]

Thanks, @corykinney ... this looks good from my side. I'll leave it open for a couple of days in case anyone else has anything to add.

Merge conflict.

[ischoegl]

@corykinney ... it looks like there now is a merge conflict due to recent upstream changes (#1501 moved consistency tests to a separate test). Could you rebase?

[corykinney]

@corykinney ... it looks like there now is a merge conflict due to recent upstream changes (#1501 moved consistency tests to a separate test). Could you rebase?

@ischoegl Just force pushed with the rebased commits

[speth]

Thanks, @corykinney, and my apologies for introducing the merge conflict with this. I had just one small suggestion before this is merged.

[speth]

Thanks for the quick update, @corykinney. However, I think your commits are now out of order, such that building from some of the intermediate ones will fail. I think it should be:

1. Add virtual method to ThermoPhase and implementation for IdealGasPhase
2. Add the implementations for P-R and R-K
3. Add the consistency test
4. Update the example

[corykinney]

Thanks for the quick update, @corykinney. However, I think your commits are now out of order, such that building from some of the intermediate ones will fail. I think it should be:

1. Add virtual method to `ThermoPhase` and implementation for `IdealGasPhase`

2. Add the implementations for P-R and R-K

3. Add the consistency test

4. Update the example

@speth The changes should be grouped and ordered properly now. Thanks for your patience! Let me know if there is anything else.

[speth]

Thanks for taking care of these details, @corykinney!