PANKH - v1.1.0

Full Changelog: v1.0.0...v1.1.0

v1.0.0

PANKH v1.0.0 Release Notes

Release Title: Initial Public Release of PANKH
Release Version: v1.0.0
Release Date: September 2, 2025
Release Note Version: 1.0
Date of Release Note: September 2, 2025

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Summary of Changes

PANKH v1.0.0 is the first official public release of our unsteady potential flow solver specifically designed for hovering airfoils. This version includes:

• A vortex panel-based unsteady aerodynamic solver
• Modular JSON-based input configuration
• Wake roll-up modeling with real-time visualization
• Time-accurate force output (Cl, Cd)
• Initial test framework using GitHub Actions

This release lays the groundwork for future research and development in the field of bio-inspired flapping wing aerodynamics and unsteady potential flow solvers.

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Detailed Description of Changes and Features

1. Unsteady Vortex Panel Solver

• Implements an unsteady 2D potential flow solver based on the vortex panel method.
• Designed to simulate flapping, plunging, and pitching airfoils in hover or forward flight.
• Accurate wake modeling with discrete shed vortices and dynamic wake roll-up.

2. JSON-Based Modular Input

• All simulation parameters are passed through an easy-to-edit input.json file.
• Parameters include airfoil geometry, motion type, time stepping, and solver controls.
• This eliminates the need for recompilation when modifying simulation inputs.

3. Aerodynamic Output

• Time-dependent lift and drag coefficients (Cl, Cd) are written to the output_files/ directory.
• Output files are automatically named using motion type, reduced frequency, and number of time steps.
• Facilitates comparison across simulations and supports automated testing.

4. Visualization with Gnuplot

• Integrated real-time visualization of the wake roll-up using GNUplot.
• Helps track the shed vortices positions in the wake.
• Gives the real time visualisation of the elolution of lift forces with respect to time.

5. Test Automation using GitHub Actions

• Includes a basic test.cpp that compares the solver's output to reference data.
• GitHub Actions (.github/workflows/CI.yml) automatically runs tests on each push.
• Supports continuous integration (CI) to ensure solver stability and reproducibility.

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Troubleshooting Tips and Resources

• Compilation Issues:
  Make sure you're using a C++11 (or newer) compiler. Use the following example:

  g++ -o PANKH_solver src/*.cpp -Iinclude -std=c++11

• Missing Dependencies:

  • Ensure Eigen is correctly installed or included.
  • GNUplot must be installed and available in your system path.

• Input Errors:

  • Check the syntax of input.json using an online JSON validator.
  • Ensure physical parameters (freestream velocity, angle of attack, amplitude) are reasonable.

• Test Failures:

  • Compare your output with the reference using diff or rerun the test binary.
  • Reference data is stored in tests/ and checked using a defined tolerance.

• Runtime Permission Issues:

  • Run chmod +x PANKH_solver if your system blocks the binary due to lack of execution permissions.

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Contact Information

If you have suggestions, want to report issues, or contribute, feel free to reach out:

• Developers: *Rohit Chowdhury, Nipun Arora, Ashish Pathak
• Email: *[email protected]
• GitHub: https://github.com/coding4Acause/PANKH

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Thank you for trying out PANKH. We welcome your support, suggestions, and contributions to help improve this solver and expand it into new domains like 2D-3D FSI and real-time visualization.