ENH: Add Eccentricity to Stochastic Simulations

[kevin-alcaniz]

Pull request type

• Code changes (bugfix, features)

Checklist

• Tests for the changes have been added (if needed)
• Docs have been reviewed and added / updated
• Lint (black rocketpy/ tests/) has passed locally
• All tests (pytest tests -m slow --runslow) have passed locally
• CHANGELOG.md has been updated (if relevant)

Current behavior

Currently, it isn't possible to add CP and thrust eccentricities to the StochasticRocket class. As a result, these eccentricities can't be evaluated in the Monte Carlo simulations.

I also found out a BUG related to thrust eccenticities in the Rocket and Flight classes!!!

New behavior

• Rocket class:
  I updated the documentation for the add_cm_eccentricity, add_cm_eccentricity and add_thrust_eccentricity functions to better clarify that these eccentricities are relative to center of DRY mass.
  BUG in add_thrust_eccentricity function: self.thrust_eccentricity_y was incorrectly assigned using the x coordinate and self.thrust_eccentricity_x using the y coordinate.

• Flight class:
  BUG: The moments due to thrust eccentricity were miscalculated. They should be computed as follows:
  

• StochasticRocket class:
  Two new functions have been introduced: add_cp_eccentricity and add_thrust_eccentricity. These allow for defining a probabilistic distibution for their values. If not used, eccentricities remain undefined. If no inputs are provided, they default to the values used in the deterministic rocket. A new function _validate_eccentricity function was created to validate eccentricity inputs.
  A new _create_eccentricities fucntion was implemented to generate random eccentricity values. These values are then assigned to the sample rocket in the create_object function.

Breaking change

• Yes
• No

[kevin-alcaniz]

There are also changes related to another PR: BUG: fix the wind velocity factors usage and better visualization of uniform distributions in Stochastic Classes #783

[kevin-alcaniz]

I'm not passing the tests because you consider it valid that thrust_eccentricity_y = x and thrust_eccentricity_x = y. Why do you do that?? Wouldn't it be more intuitive to do it my way??

Anyway, even if you still want to mantain your nomenclature, there's still a BUG in u_dot_generalized in the Flight class. The moment M2 due to thrust eccentricity should be negative, but it's currently possitive (M2 -= - self.rocket.thrust_eccentricity_y * thrust is equivalent to M2 += self.rocket.thrust_eccentricity_y * thrust which is incorrect)

[Gui-FernandesBR]

LGTM, just need to check if the stochastic_model file is correctly set here

[codecov]

Codecov Report

Attention: Patch coverage is 28.57143% with 25 lines in your changes missing coverage. Please review.

Project coverage is 79.31%. Comparing base (7348053) to head (b028e00).
Report is 1 commits behind head on develop.

Files with missing lines	Patch %	Lines
rocketpy/stochastic/stochastic_rocket.py	19.35%	25 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #792      +/-   ##
===========================================
- Coverage    79.48%   79.31%   -0.18%     
===========================================
  Files           96       96              
  Lines        11504    11537      +33     
===========================================
+ Hits          9144     9150       +6     
- Misses        2360     2387      +27     

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