Update docs news and project

Author: 1-Bart-1

NEWS.md

@@ -1,3 +1,20 @@
+## VortexStepMethod v3.1.0 2026-03-18
+
+### Added
+- `BILLOWING` panel distribution with circular arc TE billowing between ribs
+- `billowing_angle` field on `Wing` and `WingSettings`
+- `billowing_angle_from_percentage()` utility function
+- `billowing.jl` example comparing flat vs billowed V3 kite
+- Coarse V3 kite geometry, settings, and combined CFD polar data
+- `cl_over_cd` keyword for `plot_polars` and `plot_combined_analysis`
+
+### Changed
+- Plot legends moved to shared horizontal legend at bottom of grid layouts
+
+### Fixed
+- Domain error in elliptical gamma distribution when control points lie
+  outside the nominal span envelope
+
 ## VortexStepMethod v3.0.1 2025-03-17
 ### Changed
 - the file `CITATION.cff`

Project.toml

@@ -1,7 +1,7 @@
 name = "VortexStepMethod"
 uuid = "ed3cd733-9f0f-46a9-93e0-89b8d4998dd9"
 authors = ["1-Bart-1 <bart@vandelint.net>", "Oriol Cayon and contributors"]
-version = "3.0.1"
+version = "3.1.0"
 
 [deps]
 Colors = "5ae59095-9a9b-59fe-a467-6f913c188581"

docs/src/examples.md

@@ -121,6 +121,7 @@ You should see the following menu:
 ```
 Choose function to execute or `q` to quit:
  > V3_kite = include("V3_kite.jl")
+   billowing = include("billowing.jl")
    pyramid_model = include("pyramid_model.jl")
    rectangular_wing = include("rectangular_wing.jl")
    ram_air_kite = include("ram_air_kite.jl")

docs/src/functions.md

@@ -8,6 +8,7 @@ refine!
 calculate_span
 calculate_projected_area
 load_polar_data
+billowing_angle_from_percentage
 ```
 
 ## Setting the inflow conditions and solving