Propeller

• Julia implementation of Davoudi's [1] hybrid blade element momentum (BEM) model
• Linear inflow (default: Pitt-Peters) model coupled with BEM
• Multi-threaded (if Julia is started with multiple threads)
• Corrections:
  • Hub/tip-loss correction by Prandtl [2]
  • Mach correction of polars by Glauert (note: use polar data generated at $M=0.0$ for accurate correction)
  • Rotational 3D correction for polars (offline, online)

Installation

1. Setup Python for Use with PyCall

Create a new Conda env:

conda create -n julia python==3.10
conda activate julia
pip install proplot # install some packages

# show python path
which python

Build Julia's PyCall with this Python version:

pkg> add PyCall
julia> using PyCall
ENV["PYTHON"] = "path_to_python"
julia> using Pkg
julia> build("PyCall")

# Test
julia> pyversion # --> this should give the correct python version!
julia> pplt = pyimport("proplot") # --> this should load proplot from Python

2. Install Propeller.jl

Clone the repo to your path:

git clone https://github.com/christianhauschel/Propeller.jl <mypath>
cd <mypath>
julia --threads=4 --project=.

Inside of Julia, add the following nonlisted packages:

import Pkg
url = "https://github.com/christianhauschel/"
packages = (
    ("PrettySections.jl", nothing),
    ("AirfoilFast.jl", nothing),
    ("AirfoilPolars.jl", nothing),
    ("Gradient.jl", nothing),
    ("FlightConditions.jl", nothing),
    ("GeometricTools.jl", nothing),
    ("GridSpacing.jl", nothing),
)
Pkg.add([Pkg.PackageSpec(; url=url * name, rev=v) for (name, v) in packages])

Usage

julia> include("example.jl")

Useful Scripts

• rotor_calculations.jl: make different calculations a priori, e.g. to figure out the approx. Reynolds number range for the polar calculation
• misc/export_dust.jl: exports rotor to dust geometry input file
• misc/export_flowunsteady.jl: exports rotor to FLOWUnsteady

Validation

Test Cases

Simple comparison with uniform inflow (APC11x47):

Comparison with Measurements

Data taken from Davoudi [1]:

Normal and Tangential Loads / Span

Comparison to FLOWUnsteady BEM code:

Conventions

References

1. B. Davoudi, “A Hybrid Blade Element Momentum Model for Flight Simulation of Rotary Wing Unmanned Aerial Vehicles,” AIAA Paper, 2019.
2. https://flow.byu.edu/FLOWUnsteady/examples/rotorhover-aero/