PteraSoftware 0.3.1

This is an open-source, unsteady aerodynamics solver for analyzing flapping-wing flight.

Ptera Software

This is Ptera Software: a fast, easy-to-use, and open source package for analyzing flapping-wing flight.

Motivation

Around a year ago, I became curious about biological flight. To sate this curiosity, I wanted to computationally simulate some flapping-wing fliers. I quickly realized I had two options:

1. Spend thousands of dollars on a closed-source CFD program, which would take hours to solve a simple case.
2. Try to learn someone else's open source, unsteady solver written in a language I didn't know, and using a framework that is overly complicated for my use case.

Neither of these seemed like a good choice.

Thankfully, my friend, Peter Sharpe had just released his own open-source aerodynamics solver: AeroSandbox. With his blessing, I have used AeroSandbox as a jumping off point to develop a solver package capable of unsteady simulations.

Through the combined efforts of Peter Sharpe, Suhas Kodali, and myself, Ptera Software was born. It is the only fast, easy-to-use, and open-source package I know of that is capable of analyzing flapping wing flight. Moreover, it's written in Python, is well documented, and is well tested.

With your help, I hope we will improve the open-source communities interest and understanding of biological flight.

How to Install

First things first, you will need a copy of Python 3.7.6 or 3.7.7. Download it from the official Python website. At this time, I do not recommend using a version from the Anaconda distribution as it could introduce compatibility issues with PyPI.

There are a few ways to install Ptera Software. If you wish to use this package as a dependency in your own projects, simply run:

pip install PteraSoftware

via command prompt in your project's directory.

If you just want to play around with the software, feel free to fork this repository and open the source code in the IDE of your choice. You will then need to run:

pip install -r REQUIREMENTS.txt

via command prompt in your fork's directory.

Requirements

Here are the requirements necessary to run Ptera Software:

• matplotlib >= 3.2.2, < 4.0.0
• numpy >= 1.18.5, < 1.19.0
• pyvista >= 0.25.3, < 1.0.0
• scipy >= 1.5, < 2.0

What if I am Having Trouble Getting the Package Up And Running?

Not to worry! I working on releasing a video that walks through getting Ptera Software up and running. It will include every step, from downloading Python for the first time, to setting up your IDE to run it. Feel free to reach out for guidance. You can reach me at [e-mail].

How to Use

By reading this file, you are already off to a good start! After installing Ptera Software in the way that best suits your use case, the next step would be to open the examples directory, and read through each heavily commented script. Each one will give you insight into the software's interface. After you finish reading, try running them and admiring the pretty output!

Example Code

The following code snippet is all that is needed (after running pip install pterasoftware), run the steady horseshoe solver on a custom airplane object.

import pterasoftware as ps

example_airplane = ps.geometry.Airplane(
    wings=[
        ps.geometry.Wing(
            symmetric=True,
            wing_cross_sections=[
                ps.geometry.WingCrossSection(
                    airfoil=ps.geometry.Airfoil(name="naca2412",),
                ),
                ps.geometry.WingCrossSection(
                    y_le=5.0, airfoil=ps.geometry.Airfoil(name="naca2412",),
                ),
            ],
        ),
    ],
)

example_operating_point = ps.operating_point.OperatingPoint()

example_problem = ps.problems.SteadyProblem(
    airplane=example_airplane, operating_point=example_operating_point,
)

example_solver = ps.steady_horseshoe_vortex_lattice_method.SteadyHorseshoeVortexLatticeMethodSolver(
    steady_problem=example_problem
)

example_solver.run()

ps.output.draw(
    solver=example_solver, show_delta_pressures=True, show_streamlines=True,
)

Example Output

This package currently supports three different solvers, a steady horseshoe vortex lattice method (VLM), a steady ring VLM, and an unsteady ring VLM. Here are examples of the output you can expect to receive from each of them.

Steady Horseshoe VLM

Steady Ring VLM

Unsteady Ring VLM

How to Contribute

As I said before, the primary goal of this project is to increase the open source communities understanding and appreciation for unsteady aerodynamics in general, and flapping-wing flight in particular. This will only happen through your participation. Feel free to request features, report bugs and security issues, and to provide suggestions. No comment is to big or small!

Note: This is my first attempt at creating a Python project this size, and at managing a public repository. I am bound to make mistakes but I am determined to listen to your feedback and to use it to improve.

Credits

Here is a list, in no particular order, of all the people and packages that helped me created Ptera Software. Specific citations can be found in the source code's docstrings where applicable.

• Suhas Kodali
• Peter Sharpe
• Joseph Katz
• Allen Plotkin
• AeroSandbox
• Black
• Coverage
• Travis CI
• NumPy
• SciPy
• PyVista
• MatPlotLib
• Pre-Commit
• SetupTools
• GitIgnore
• Shields.io
• PyPI
• Wheel
• Twine
• SemVer
• GitFlow

Notes

To the best of my ability, I am following SemVer conventions in naming my releases. I am also using the GitFlow method of branching for this project's development. This means that nightly builds will be available on the develop branch, and the latest stable releases can be found on the master branch.