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CurrentModule = VortexStepMethod

Rectangular Wing

Wing Aerodynamics Analysis using Vortex-Step Method (VSM) and Lift Line Theory (LLT)

This example demonstrates the process of setting up and analyzing a wing's aerodynamics using VSM and LLT. We'll cover the following steps:

  1. Importing necessary libraries.
  2. Define the wing parameters
  3. Create wing geometry with linear panel distribution and add the wing sections
  4. Initializing the wing aerodynamics and set the inflow conditions.
  5. Initialize solvers for both LLT and VSM methods
  6. Running a simulation with both methods
  7. Plotting combined analysis

First, install Julia and set up the examples environment as explained in the section Running the examples as developer. Then launch Julia:

julia --project=examples

Step 1: Importing the necessary libraries:

julia> using LinearAlgebra
julia> using GLMakie
julia> using VortexStepMethod

Step 2: Define wing parameters

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> alpha_deg = 30.0       # Angle of attack [degrees]
julia> alpha = deg2rad(alpha_deg)

Step 3: Create wing geometry with linear panel distribution

julia> wing = Wing(n_panels, spanwise_distribution=LINEAR)
Add wing sections - defining only tip sections with inviscid airfoil model
julia> add_section!(wing,
           [0.0, span/2, 0.0],   # Left tip LE
           [chord, span/2, 0.0],  # Left tip TE
           INVISCID)
julia> add_section!(wing,
           [0.0, -span/2, 0.0],  # Right tip LE
           [chord, -span/2, 0.0], # Right tip TE
           INVISCID)
Refine the mesh
julia> refine!(wing)

Step 4: Initialize aerodynamics

julia> body_aero = BodyAerodynamics([wing])

We need to pass here an array of wing objects, because a body can have multiple wings.

Set inflow conditions
julia> vel_app = [cos(alpha), 0.0, sin(alpha)] .* v_a
julia> set_va!(body_aero, vel_app, [0, 0, 0.1])

Step 5: Initialize solvers for both LLT and VSM methods

julia> llt_solver = Solver(body_aero; aerodynamic_model_type=LLT)
julia> vsm_solver = Solver(body_aero; aerodynamic_model_type=VSM)

Step 6: Solve using both methods

julia> results_llt = solve(llt_solver, body_aero)
julia> results_vsm = solve(vsm_solver, body_aero)
Print results comparison
julia> println("\nLifting Line Theory Results:")
julia> println("CL = $(round(results_llt["cl"], digits=4))")
julia> println("CD = $(round(results_llt["cd"], digits=4))")
julia> println("\nVortex Step Method Results:")
julia> println("CL = $(round(results_vsm["cl"], digits=4))")
julia> println("CD = $(round(results_vsm["cd"], digits=4))")
julia> println("Projected area = $(round(results_vsm["projected_area"], digits=4)) m²")

Step 7: Plot combined analysis

julia> angle_range = range(0, 20, 20)
julia> plot_combined_analysis(
           [llt_solver, vsm_solver],
           [body_aero, body_aero],
           [results_llt, results_vsm];
           solver_label=["LLT", "VSM"],
           angle_range=angle_range,
           angle_type="angle_of_attack",
           v_a=v_a,
           title="Rectangular Wing",
           is_show=true,
       )

More examples

After launching Julia with (jl), you can execute more examples by typing:

julia> include("examples/menu.jl")

or, you prefer to use the ControlPlots library:

julia> include("examples_cp/menu_cp.jl")

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")
   stall_model = include("stall_model.jl")
   bench = include("bench.jl")
   cleanup = include("cleanup.jl")
   GLMakie.activate!()
   CairoMakie.activate!()
   help_me = VortexStepMethod.help("https://opensourceawe.github.io/VortexStepMethod.jl/dev")
   quit

You can select one of the examples using the <UP> and <DOWN> keys. Press <ENTER> to run the selected example.

Plotting Backends

The examples in this package support three plotting backends. Here is a comparison to help you choose:

GLMakie

Advantages:

  • Interactive plots: zoom, pan, rotate 3D scenes in a native window.
  • Hardware-accelerated rendering via OpenGL — fast for large datasets.
  • Supports animations and live-updating plots.

Disadvantages:

  • Requires a display server (does not work in headless/server environments without a virtual framebuffer).
  • Heavier dependency: needs OpenGL drivers and a GPU.
  • Longer initial load time compared to ControlPlots

CairoMakie

Advantages:

  • Fully software-rendered — works in headless environments (CI, servers, SSH sessions).
  • Produces high-quality vector output (SVG, PDF) suitable for publication for 2D plots. The quality of 3D plots is not yet suitable for publications, though.

Disadvantages:

  • Plots are static — no interactive zoom or pan.
  • Slower for very large or complex scenes because rendering is done in software.
  • 3D support is limited compared to GLMakie.
  • Longer initial load time compared to ControlPlots

ControlPlots (based on PyPlot / Matplotlib)

Advantages:

  • Simple API, easy to learn for students
  • In addition, the Matplotlib API for users coming from Python/Matplotlib is supported.
  • Works in headless environments; can save to PNG, SVG, PDF, etc.
  • Very lightweight Julia-side dependency (delegates work to Python).

Disadvantages:

  • Requires a working Python installation with Matplotlib (via PyCall).
  • Might crash when multithreading is enabled. Start Julia with -t 1,0 to avoid problems.
  • No native Makie ecosystem integration (e.g. cannot use Makie.Observable for live updates).
  • Interactivity is limited and depends on the Matplotlib backend in use.
  • Extra setup complexity when Python or Matplotlib are not already installed.
Feature GLMakie CairoMakie ControlPlots
Interactive (zoom/pan) yes no yes
Headless / server no* yes yes
Vector output (PDF/SVG) no yes yes
GPU required yes no no
3D support full limited limited
Load time slow medium fast

* GLMakie can run headless with a virtual framebuffer (e.g. Xvfb), but this requires additional setup.