ENH: Improve parachute geometric parametrization #835
+124
−11
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
There was a problem hiding this comment.
Pull Request Overview
This PR improves the parachute geometric parametrization by introducing new parameters (radius, height, and porosity) to provide a more flexible and accurate simulation. Key changes include:
- Adding lambda callbacks to update parachute_radius, parachute_height, and parachute_porosity in the simulation.
- Updating the added mass computation in flight dynamics to use parachute_radius and parachute_height.
- Extending the Parachute class to support the new parameters, with appropriate defaults and serialization.
Reviewed Changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
| rocketpy/simulation/flight.py | Updated simulation callbacks and mass computation with new parameters. |
| rocketpy/rocket/parachute.py | Extended the Parachute class to include and serialize new parameters. |
Comments suppressed due to low confidence (2)
rocketpy/simulation/flight.py:2002
- [nitpick] Consider adding a comment to explain the rationale behind the modified added mass formula using parachute_radius squared times parachute_height, clarifying the geometrical model or assumptions used.
ma = ka * rho * (4 / 3) * np.pi * parachute_radius**2 * parachute_height
rocketpy/simulation/flight.py:2018
- Ensure that the variable 'z' is defined in this scope (for example, by extracting altitude from the state vector) to avoid potential runtime errors.
az = (Dz - mp * self.env.gravity.get_value_opt(z)) / (mp + ma)
MateusStano
approved these changes
Jul 4, 2025
Comment on lines
+1511
to
+1514
| porosity : float, optional | ||
| Porosity of the parachute material, which is a measure of how much air can | ||
| pass through the parachute material. | ||
| Default value is 0.0432 (for consistency with previous versions). |
There was a problem hiding this comment.
Could you define more precisely what porosity is? Something like: "The ratio of the area of the porous structure to the total area of the canopy" (I don't know if this is the correct definition in our case, just an example)
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Pull request type
Checklist
black rocketpy/ tests/) has passed locallypytest tests -m slow --runslow) have passed locallyCHANGELOG.mdhas been updated (if relevant)Current behavior
Parachute radius is assumed to be fixed (=1.5m)
New behavior
Other than adding a radius parameter, there is also additional height and porosity parameters.
The default is still set to the current behavior.
Breaking change