Merge branch 'main' into agent/275-section-slicing-spreads-stations-by-lead

Author: 1-Bort-1

CHANGELOG.md

@@ -2,6 +2,22 @@
 
 ## Unreleased
 
+### Added
+
+- `set_va!(body_aero, va_vec, omega; reference_point)` turns the body about
+  `reference_point` [m] instead of the origin. The point is stored on
+  `BodyAerodynamics`, starts at the origin, and is kept by later `set_va!`, `reinit!`
+  and `linearize` calls until it is given again.
+- Spanwise-flow viscous drag correction (Gaunaa et al. 2024,
+  doi:10.1088/1742-6596/2767/2/022068): each section gets a drag increment and a force
+  along its span from the flow across it, in `solve!`, `solve` and `linearize`. Opt-in
+  via `is_with_viscous_drag_correction` (default `false`) on the solver settings.
+- `plot_section_polars(body_aero; panels, alphas, delta)` draws cl, cd and cm against α
+  per panel through `calculate_cl`/`calculate_cd`/`calculate_cm`, for every aero model
+  and at flap deflection `delta`, in one figure instead of one coefficient per call.
+- `linearize` takes a `BodyAerodynamics` with more than one wing; `theta_idxs` and
+  `delta_idxs` then run over the unrefined sections of all wings in order.
+
 ### Changed
 
 - Requires Julia 1.12 or 1.13; 1.10 and 1.11 keep resolving v5.1.1.
@@ -18,8 +34,15 @@
 
 ### Fixed
 
+- `set_va!(body_aero, settings)` applies `condition.yaw_rate` as a turn rate about the
+  body z axis; it was read from the settings file and ignored.
 - The `VSMSolution` docstring gives `lift_dist`, `drag_dist` and `panel_moment_dist` in
   the per-unit-span units they hold, [N/m] and [Nm/m], instead of [N] and [Nm].
+- Inside its vortex core, `velocity_3D_trailing_vortex!` induces an azimuthal velocity
+  instead of a radial one. Only points within the millimetre-scale Oseen core of a
+  panel's chordwise trailing segment were affected.
+- With `artificial_damping` on, an iteration whose circulation is already smooth no longer
+  re-applies the previous iteration's damping correction.
 
 ## VortexStepMethod v5.1.1 2026-09-12
 

README.md

@@ -89,7 +89,7 @@ Three kinds of input data is needed:
   - kite wing: model of polars included, n sections to define
 
 - The airflow and turn rate:
-  - `v_app` vector and `omega` (turn rate) vector in Kite Body (KB) reference frame
+  - `va_vec` vector and `omega` (turn rate) vector in Kite Body (KB) reference frame
 
 - The configuration:
   - how many panels  
@@ -106,7 +106,7 @@ A whole run — the flight condition, each wing and the solver — is configured
 n_panels = 20          # Number of panels
 span = 20.0            # Wing span [m]
 chord = 1.0            # Chord length [m]
-v_a = 20.0             # Magnitude of inflow velocity [m/s]
+va = 20.0              # Magnitude of inflow velocity [m/s]
 density = 1.225        # Air density [kg/m³]
 alpha_deg = 30.0       # Angle of attack [degrees]
 alpha = deg2rad(alpha_deg)
@@ -131,8 +131,8 @@ refine!(wing)
 body_aero = BodyAerodynamics([wing])
 
 # Set inflow conditions
-vel_app = [cos(alpha), 0.0, sin(alpha)] .* v_a
-set_va!(body_aero, vel_app)
+va_vec = [cos(alpha), 0.0, sin(alpha)] .* va
+set_va!(body_aero, va_vec)
 ```
 It is possible to import the wing geometry using an `.obj` file as shown in the example `ram_air_kite.jl`. During the import the polars are calculated automatically using XFoil. This approach is valid for rigid wings and ram-air kites, but not for leading edge inflatable kites.
 

docs/src/examples.md

@@ -35,7 +35,7 @@ julia> using VortexStepMethod
 julia> n_panels = 20          # Number of panels
 julia> span = 20.0            # Wing span [m]
 julia> chord = 1.0            # Chord length [m]
-julia> v_a = 20.0             # Magnitude of inflow velocity [m/s]
+julia> va = 20.0              # Magnitude of inflow velocity [m/s]
 julia> alpha_deg = 30.0       # Angle of attack [degrees]
 julia> alpha = deg2rad(alpha_deg)
 ```
@@ -77,8 +77,8 @@ multiple wings.
 ###### Set inflow conditions
 
 ```julia
-julia> vel_app = [cos(alpha), 0.0, sin(alpha)] .* v_a
-julia> set_va!(body_aero, vel_app, [0, 0, 0.1])
+julia> va_vec = [cos(alpha), 0.0, sin(alpha)] .* va
+julia> set_va!(body_aero, va_vec, [0, 0, 0.1])
 ```
 
 #### Step 5: Initialize solvers for both LLT and VSM methods
@@ -118,7 +118,7 @@ julia> plot_combined_analysis(
            solver_label=["LLT", "VSM"],
            angle_range=angle_range,
            angle_type="angle_of_attack",
-           v_a=v_a,
+           v_a=va,
            title="Rectangular Wing",
            is_show=true,
        )

docs/src/index.md

@@ -94,7 +94,7 @@ Three kinds of input data is needed:
   - kite wing: model of polars included, n sections to define
 
 - The airflow and turn rate:
-  - `v_app` vector and `omega` (turn rate) vector in Kite Body (KB) reference frame
+  - `va_vec` vector and `omega` (turn rate) vector in Kite Body (KB) reference frame
 
 - The configuration:
   - how many panels  
@@ -112,7 +112,7 @@ A whole run — the flight condition, each wing and the solver — is configured
 n_panels = 20          # Number of panels
 span = 20.0            # Wing span [m]
 chord = 1.0            # Chord length [m]
-v_a = 20.0             # Magnitude of inflow velocity [m/s]
+va = 20.0              # Magnitude of inflow velocity [m/s]
 density = 1.225        # Air density [kg/m³]
 alpha_deg = 30.0       # Angle of attack [degrees]
 alpha = deg2rad(alpha_deg)
@@ -137,8 +137,8 @@ refine!(wing)
 body_aero = BodyAerodynamics([wing])
 
 # Set inflow conditions
-vel_app = [cos(alpha), 0.0, sin(alpha)] .* v_a
-set_va!(body_aero, vel_app)
+va_vec = [cos(alpha), 0.0, sin(alpha)] .* va
+set_va!(body_aero, va_vec)
 ```
 
 It is possible to import the wing geometry using an `.obj` file as shown in the example `ram_air_kite.jl`. During the import the polars are calculated automatically, using NeuralFoil by default or XFoil as a viscous cross-check. This approach is valid for rigid wings and ram-air kites, but not for leading edge inflatable kites. See [From CAD mesh to aerodynamic model](@ref) for the full pipeline.

docs/src/private_functions.md

@@ -52,6 +52,7 @@ effective_alpha
 panel_inflow
 dynamic_pressure
 flow_curvature_cm
+spanwise_flow_drag
 panel_force_directions
 panel_moment
 panel_couple_force
@@ -62,6 +63,7 @@ panel_loads
 ```@docs
 velocity_3D_bound_vortex!
 velocity_3D_trailing_vortex!
+velocity_3D_vortex_segment!
 velocity_3D_trailing_vortex_semiinfinite!
 calculate_velocity_induced_bound_2D!
 calculate_velocity_induced_single_ring_semiinfinite!
@@ -82,6 +84,7 @@ calculate_filaments_for_plotting
 ### Mesh refinement and billowing
 ```@docs
 unrefined_deform!
+unrefined_section_range
 deform!
 compute_refined_panel_mapping!
 compute_refined_section_interpolation!
@@ -273,6 +276,7 @@ panel_contour
 panel_normal
 plate_hinge_local
 panel_plate_geometry
+panel_polar_curves
 PLATE_FACES
 Makie.plot!(ax, panel::VortexStepMethod.Panel)
 Makie.plot!(ax, body::VortexStepMethod.BodyAerodynamics)

docs/src/reference_frames.md

@@ -3,7 +3,7 @@
 ### Introduction
 Reference frames are needed for following purposes:
 - for creating a CAD model of the wing (or the wings)
-- for defining the apparent wind speed vector $v_a$
+- for defining the apparent wind speed vector `va_vec`
 - for calculating the lift and drag and side force coefficients
 - for calculating the resulting forces and moments
 
@@ -30,6 +30,6 @@ The turn rates $\mathrm{omega} = [\mathrm{omega_x}, \mathrm{omega_y} ,\mathrm{om
 
 ## Input and output
 - when running a simulation, the turnrate of the kite must be provided on each time step
-- the apparent wind speed vector `v_a` is defined in the **KB** reference frame
+- the apparent wind speed vector `va_vec` is defined in the **KB** reference frame
 - the resulting forces are defined in the **KB** reference frame
 - the **CL**, **CD**, **CS** and the resulting moments and moment coefficients are defined in the **KB** reference frame

docs/src/settings.md

@@ -32,7 +32,7 @@ condition:
   wind_speed: 10.0                # free-stream velocity magnitude [m/s]
   alpha: 5.0                      # angle of attack [°]
   beta: 0.0                       # sideslip angle [°]
-  yaw_rate: 0.0                   # yaw rate [°/s]
+  yaw_rate: 0.0                   # turn rate about the body z axis [°/s]
 
 wings:
   - name: main_wing               # label the wing carries into plots and output

examples/V3_kite.jl

@@ -141,7 +141,7 @@ PLOT && plot_distribution(
     [body_y_coordinates],
     [results],
     ["VSM"];
-    title="CAD_spanwise_distributions_alpha_$(round(angle_of_attack_deg, digits=1))_delta_$(round(sideslip_deg, digits=1))_yaw_$(round(yaw_rate, digits=1))_v_a_$(round(wind_speed, digits=1))",
+    title="CAD_spanwise_distributions_alpha_$(round(angle_of_attack_deg, digits=1))_delta_$(round(sideslip_deg, digits=1))_yaw_$(round(yaw_rate, digits=1))_va_$(round(wind_speed, digits=1))",
     save_path=OUTPUT_DIR,
     is_save=false || SAVE_ALL,
     is_show=true,

examples/V3_neuralfoil.jl

@@ -69,7 +69,7 @@ nf_yaml = obj_to_yaml(OBJ_PATH, gen_dir; n_sections=N_SLICES, Re=RE,
     rotation=ROTATION, wrap_method=WRAP, aero_solver=NF_SOLVER, verbose=true)
 
 # Flight conditions
-v_a = 10.0
+va = 10.0
 angle_range = range(-5, 25, length=31)
 
 # Load settings and create wing with CFD polars
@@ -105,7 +105,7 @@ fig = plot_polars(
      "Wind tunnel (Poland 2025)"];
     literature_path_list=literature_paths,
     angle_range,
-    v_a,
+    v_a=va,
     title="TU Delft V3 Kite: CFD vs NeuralFoil (Re=$RE)",
     is_save=false,
 )

examples/bench.jl

@@ -12,7 +12,7 @@ using VortexStepMethod: solve_base!
 n_panels = 20          # Number of panels
 span = 20.0            # Wing span [m]
 chord = 1.0            # Chord length [m]
-v_a = 20.0             # Magnitude of inflow velocity [m/s]
+va = 20.0              # Magnitude of inflow velocity [m/s]
 density = 1.225        # Air density [kg/m³]
 alpha_deg = 30.0       # Angle of attack [degrees]
 alpha = deg2rad(alpha_deg)
@@ -37,8 +37,8 @@ refine!(wing)
 body_aero = BodyAerodynamics([wing])
 
 # Set inflow conditions
-vel_app = [cos(alpha), 0.0, sin(alpha)] .* v_a
-set_va!(body_aero, vel_app)
+va_vec = [cos(alpha), 0.0, sin(alpha)] .* va
+set_va!(body_aero, va_vec)
 
 # Step 4: Initialize solvers for both LLT and VSM methods
 llt_solver = Solver(body_aero; aerodynamic_model_type=LLT)
@@ -73,17 +73,17 @@ vsm_solver = Solver(
 )
 
 # Setting velocity conditions
-v_a = 15.0
+va = 15.0
 aoa = 15.0
 side_slip = 0.0
 yaw_rate = 0.0
 aoa_rad = deg2rad(aoa)
-vel_app = [
+va_vec = [
     cos(aoa_rad) * cos(side_slip),
     sin(side_slip),
     sin(aoa_rad)
-] * v_a
-set_va!(body_aero, vel_app)
+] * va
+set_va!(body_aero, va_vec)
 
 # Solving
 solve_base!(vsm_solver, body_aero, nothing)