v2.0.02

• #152 add test of correction (eae1cb6)
• Change aoa 1/4 correction as optional bool in solver, false by default (#152) (72439c8)
• changed tutorial (acbfc2c)

What's Changed

• Main2 by @jellepoland in #154
• Develop by @jellepoland in #153

Full Changelog: v2.0.1...v2.0.2

v2.0.1

What's Changed

• Updating a minus sign bug, and tweaking the evaluation of static stability derivatives by @jellepoland in #151

Full Changelog: v2.0.0...v2.0.1

Added

• evaluate_stability_derivatives.py example script demonstrating the use of the new
  compute_rigid_body_stability_derivatives() function for calculating aerodynamic stability derivatives, prints results at trim conditions in the kite reference frame (x-backward LE to TE, y-right from kite's perspective, z-up) and in the aircraft convention (x-forward, y-right, z-down).

Fixed

• Corrected a misplaced minus sign in the sideslip handling inside BodyAerodynamics.va_initialize, restoring the intended sign convention for moment predictions and β-related stability derivatives.

v2.0.0

What's Changed

• updating change log for release v1.1.0 by @jellepoland in #145
• Fix URL and add ORCID for authors in CITATION.cff by @rschmehl in #146
• Update README.md by @jellepoland in #147
• Fixing major bug in calculation of projected surface area, added stability and so on by @jellepoland in #149

New Contributors

• @rschmehl made their first contribution in #146

Full Changelog:
v1.1.0...v2.0.0

[2.0.0] - 08-10-2025

⚠️ Breaking Changes

API Changes in BodyAerodynamics

1. va.setter now requires keyword-only arguments:

The velocity setter has been completely redesigned to properly handle body angular rates and reference points. All arguments after va are now keyword-only.

Old usage (v1.1.0):

# Setting velocity with yaw rate (tuple format)
body_aero.va = (vel_app, yaw_rate)

# Or without yaw rate
body_aero.va = vel_app

New usage (v2.0.0+):

# Basic velocity setting (no body rates)
body_aero.va = vel_app

# With body rates (keyword arguments required)
body_aero.va = vel_app, roll_rate=p, pitch_rate=q, yaw_rate=r

# With custom reference point for rotational velocity
body_aero.va = vel_app, yaw_rate=r, reference_point=np.array([x, y, z])

Migration guide:

• Instead of setting it directly using body_aero.va, you can instead use va_initialize() (see below)

• If you do want to directly set it, you could should write for full control over body rates:

  body_aero.va = vel_app, roll_rate=p, pitch_rate=q, yaw_rate=r, reference_point=ref_pt

2. va_initialize() signature expanded:

The initialization method now accepts body angular rates and reference point.

Old signature (v1.1.0):

body_aero.va_initialize(Umag, angle_of_attack, side_slip, yaw_rate=0.0)

New signature (v2.0.0+):

body_aero.va_initialize(
    Umag, 
    angle_of_attack, 
    side_slip, 
    pitch_rate=0.0,      # NEW
    roll_rate=0.0,       # NEW  
    reference_point=None # NEW
)

Migration guide:

• The yaw_rate parameter has been removed
• Body rates are now specified via pitch_rate, roll_rate keywords
• If you need yaw rate, use pitch_rate parameter (body-fixed z-axis)
• Most existing code will work without changes if you weren't using yaw_rate
• If you were using yaw_rate, replace with appropriate body rate:

  # Old
  body_aero.va_initialize(Umag, alpha, beta, yaw_rate=0.5)
  
  # New (yaw is rotation about body z-axis = pitch_rate)
  body_aero.va_initialize(Umag, alpha, beta, pitch_rate=0.5)

3. Rotational velocity calculation changed:

The method for computing rotational velocity contributions has been fundamentally updated:

• Old behavior: Simple uniform yaw rate applied
• New behavior: Proper rotational velocity field: v_rot = omega × (r - r_ref)
  • Accounts for all three body angular rates (roll, pitch, yaw)
  • Reference point can be specified (defaults to panel centroids)
  • Physically accurate velocity field due to body rotation

Impact:

• Results involving body angular rates will differ from v1.1.0
• New results are physically more accurate
• If comparing with v1.1.0 results, expect differences in cases with non-zero angular rates

4. New property: _body_rates

Body angular rates are now stored and accessible via _body_rates property:

p, q, r = body_aero._body_rates  # [roll_rate, pitch_rate, yaw_rate]

Added

New Modules

1. stability_derivatives.py

• Compute rigid-body aerodynamic stability derivatives
• Function: compute_rigid_body_stability_derivatives()
• Supports derivatives w.r.t. angle of attack (α), sideslip (β), and body rates (p, q, r)
• Optional non-dimensionalization of rate derivatives
• Uses central finite differences for accuracy
• See docs/StabilityDerivatives.md for detailed documentation

2. trim_angle.py

• Find trim angle of attack where pitching moment equals zero
• Function: compute_trim_angle()
• Two-phase algorithm: coarse sweep + bisection refinement
• Automatic stability verification
• Configurable convergence tolerances
• See docs/TrimAngle.md for detailed documentation

New Documentation

• docs/StabilityDerivatives.md - Comprehensive guide to stability derivative computation
• docs/TrimAngle.md - Guide to trim angle finding with examples
• docs/README.md - Updated documentation index with quick-start guide
• Enhanced main README.md with Quick Start, Key Features, and Troubleshooting sections

New Examples

• examples/TUDELFT_V3_KITE/tow_angle_geometry.py - Visualize effect of tow angle on kite geometry
• examples/TUDELFT_V3_KITE/tow_point_location_parametric_study.py - Study tow point location effects
• examples/TUDELFT_V3_KITE/kite_stability_dynamics.py - Demonstrate stability derivative computation

Fixed

• Projected area calculation now uses correct trapezoidal integration method
• Reference point handling in rotational velocity calculations

v1.1.0

CHANGELOG [1.1.0] - 2025-09-26

⚠️ Breaking Changes

• Class rename: WingAerodynamics → BodyAerodynamics.
• Dataset path rename: TUDELFT_V3_LEI_KITE → TUDELFT_V3_KITE.
• Polar input format update:
  • 3D: alpha, CL, CD, CM
  • 2D: alpha, Cl, Cd, Cm (note the capitalization difference)
• Defaults & options:
  • Default spanwise panel distribution → uniform
  • Removed options/attributes: using_previous gamma, min_relaxation_error, is_new_vector_definition.
• Stall model refactor: Simonet-related stall logic moved out of Solver into solver_functions and a dedicated stall branch.

Added

• AirfoilAerodynamics framework

  • New base class AirfoilAerodynamics (parent for all airfoil types).
  • masure_regression airfoil with on-disk caching for fast reuse.
  • YAML configuration input for airfoil definitions.
  • New tests for AirfoilAerodynamics.

• LEI parametric model (masure_regression_lei_parametric)

  • Examples showing how to reconstruct a LEI airfoil using 6 parameters:
    t, eta, kappa, delta, lambda, phi.
  • Utilities for generating airfoil geometry and exporting .csv / .dat.

• Half-wing inputs

  • Support for half-wing inputs in both polar generation and geometry CSV export.

• Plotting & tutorials

  • Improved convergence plotting utilities.
  • New sensitivity analysis examples & script (sensitivity_analysis.py).
  • Updated tutorials (usage, sensitivity, convergence workflows).
  • Interactive Plotly visualization environment.
  • Moment calculations + plotting (incl. user-defined reference point).
  • Panel polar investigation function.

• Solver & VSM pipeline

  • Solver gains artificial viscosity (property + setter).
  • Added non-linear gamma loop variants and gamma loop type selector.
  • New compute_aerodynamic_quantities helper.
  • New initial gamma distribution options: elliptical, cosine, zero.
  • BodyAerodynamics:
    • Added/renamed circulation helpers:
      • calculate_circulation_distribution_elliptical_wing
      • calculate_circulation_distribution_cosine
  • Panel:
    • New property: panel_polar_data.
    • New _panel_aero_model option: "cl_is_pisinalpha".

• Validation & examples

  • Added elliptical wing planform test (Simonet ch. 4.1).
  • Added rectangular wing test.
  • NeuralFoil integration for cross-checking polars.
  • Git now ignores results/.

• Bridle line forces

  • Support for inputs like:
    • bridle_line1 = [p1, p2, diameter] where p1 = [x, y, z]
    • bridle_lines = [bridle_line1, bridle_line2, ...]
  • BodyAerodynamics API sugar:
    • instantiate_body_aerodynamics function
    • BodyAerodynamics.from_file(...)

Changed

• Polars & plotting

  • plotting.py::generate_3D_polar_data now passes a gamma distribution
    into the solver:
    results = solver.solve(body_aero, gamma_distrbution=gamma)
  • Legends for distributions and polars are displayed below plots.
  • Improved clarity and formatting of plot outputs.

• Solver internals

  • Revised __init__, added artificial viscosity, refactored internal state to self.* for broader accessibility.
  • Revised gamma initialization and feedback handling.
  • Adjusted Simonet model plumbing and naming (elliptic → elliptical).

• BodyAerodynamics

  • calculate_panel_properties: replaced hardcoded 0.25 / 0.75 with ac (aerodynamic center) and cp (center of pressure).

• Docs & tutorials

  • Updated docstrings, tutorials, and user guides to reflect the new APIs and behaviors.
  • Expanded convergence & sensitivity study guidance (e.g., n_panels).

• Vector conventions

  • Normalized aerodynamic vector handling for consistency across modules.

• Polar engineering

  • Updated to use Surfplan profiles; adjusted POLAR behavior and tests.

Fixed

• Polar data input robustness and format handling.
• Reference point handling in moment computations.
• Multiple failing tests in Panel.
• Plot output issues (including prior formatting issues, e.g. #85).
• Numerous docstring and minor consistency fixes.

Removed

• min_relaxation_error and is_new_vector_definition fields.
• using_previous gamma option (gamma initialization is now explicit/controlled).
• Consolidated/moved stall models into dedicated modules/branch.
• Extracted polar_engineering work to its own branch.

Migration Notes

• Imports / classes

  • Replace:

    from VSM.core import WingAerodynamics

    with:

    from VSM.core import BodyAerodynamics

• Datasets & configs

  • Update any paths from:

    TUDELFT_V3_LEI_KITE → TUDELFT_V3_KITE
    

• Polar files & arrays

  • Ensure 3D data is in: alpha, CL, CD, CM
  • Ensure 2D data is in: alpha, Cl, Cd, Cm
  • If you relied on the old format, update your CSV writers/loaders and tests accordingly.

• Solver usage

  • Specify the desired gamma initialization and loop type explicitly:

    solver.gamma_initial_distribution_type = "elliptical"  # or "cosine", "zero"
    solver.gamma_loop_type = "non_linear"                  # or "base"
    solver.artificial_viscosity =  ...                     # set as needed
    results = solver.solve(body_aero, gamma_distrbution="cosine")

  • Remove any reliance on using_previous gamma.

• Panel model

  • If you used _panel_aero_model, you can now set:

    panel._panel_aero_model = "cl_is_pisinalpha"

• Plotting

  • Legends for certain plots are now at the bottom; if you have custom layout logic, adjust figure margins accordingly.

• Half-wing workflows

  • When generating polars or exporting geometry, adjust scripts to provide half-wing inputs if desired.

• Caching (masure_regression)

  • The regression model caches results on disk; verify your ml_models_dir and cache paths are writable in CI.

What's Changed (generated)

• Develop by @jellepoland in #70
• Issue#85 by @corentintran in #86
• 105 adding bridle drag by @jellepoland in #112
• Develop by @jellepoland in #116
• 115 changing polar input to have the dimensions n4 instead of 4n by @jellepoland in #118
• Develop by @jellepoland in #121
• Stall models by @jellepoland in #134
• Merge pull request #70 from ocayon/develop by @jellepoland in #135
• Develop by @ocayon in #144

New Contributors

• @corentintran made their first contribution in #86

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

v1.0.0

• Refactor code to objected oriented. Physics remain the same as the old version. New engineering stall model added.
• Improved performance and added clear documentation and tutorials.
• The code can be packaged and installed using pip
• Pytested, (coverage 66%)
• Adhering to open-source standards.

Full Changelog: v0.1.0...v1.0.0

v0.1.0

This is the functional base of the VSM, used as the aerodynamic model for my master thesis and paper on aerostructural modeling of soft kites. Links below:

Master Thesis "Fast Aeroelastic Model of a Leading-Edge Inflatable Kite"
Paper "Fast Aero-Structural Model of a Leading-Edge Inflatable Kite"