[STARTED] Validating the flow around an APC Slow Flyer Propeller




Propellers form an integral part in thrust or lift in fixed winged aircraft as well as in multi-rotor drones. Hence, it is crucial to model the performance of the propeller in the design process. This is where simulation tools can be leveraged. Computational Fluid Dynamics helps quantify the lift and drag values which form the basis for the calculation of parameters such as:

From [1]

Here, T (N) is thrust, Q (N·m) is torque, n (rps) is the rotational speed of the propeller, D (m) is the diameter of the propeller, and ρ (kg·m−3) is the density of the fluid. The relative percentage error of the thrust coefficient, KT, and torque coefficient, KQ, can be calculated by the Equations (4) and (5).

Input Data

The proceeding figure provides an overview of the simulation setup for your simulation.

This project provides a good opportunity implement the Mixing Reference Frame (MRF) method. A detailed description about sizing the MRF zone can be obtained from the following image.

  • The geometry for the APC slow flyer can be downloaded from here.
  • The experimental results can be found on the UIUC Propeller Database. Please use the Slow Flyer 8 x 3.8 for the purpose of this validation case.


This project is intended towards validating the performance of a generic propeller geometry. Such a validation project enables the user to enhance their knowledge in leveraging CFD for modelling the performance of an existing drone or estimating the design parameters such as motor size, material property requirements, etc. during the development phase of a drone.

The user has the opportunity of assimilating and applying CFD best practices at different phases(CAD clean-up, meshing, simulation and post-processing) of the CFD process. Some such best practices include: a mesh independence study, result verification, reasonable selection of time-step size and the number of computing cores. The would be provided with significant bonus points for implementing a automation (via shell-scripts for example) at any stage of the CFD process.

Key Words

Validation, Rotor Performance, UIUC Propeller Database, Aerospace, Drones, OpenFOAM, Slow Flyer,

Literature & Sources


Started by @Filiptheking!

Propeller validation: Problem with mesh independence

I’m interested in doing this project.
However, I’m not really convinced that the geometry file provided represents the propellers actual geometry. How certain are you that the source is reliable and that it matches the real propeller?


Hi there @Filiptheking!

The task is basically validating the results from the APC slow flyer with the experimental results of the Slow Flyer 8 x 3.8. If the data do not match you can be sure that there is something wrong but that’s not the purpose of this “Solve it with SimScale” case. Feel free to send me an email with your username and the case, will provide you with support to solve this case.

All the best!