SimScale CAE Forum

Flywheel Friction

Hi all,

First time Simscaler here. I’m looking to analyse the friction on a flywheel due to air resistance.
I have set up a basic model below which represents the air space around a flywheel in a chamber - internal faces are the flywheel, external faces are the chamber.
The velocity results seem logical visually, but I don’t know if they’re correct.

In any case, I would like to know the frictional losses experienced by the flywheel in terms of N.m, as a result of air resistance. By extension, I would like to explore the relationship between air pressure (or vacuum) and frictional losses.

My model is here:

How would I go about this?

Thanks in Advance.

@CFD-SQUAD, any tips you have for our user here?



Hi Jousef,

Should I assume the lack of responses suggests this type of analysis isn’t possible?


Well, if it were easy, everybody would jump on and answer.

I can only offer following explanations:

  • Cartesian coordinate system, IMHO, seems inappropriate for flywheel simulation. Cylindrical coordinate system would allow a meaningful setup.
  • Flywheel peripheral speed would be probably supersonic for mid-size devices. This will be tough to simulate, due to instabilities.
  • Appropriate turbulence model should be searched / tested for simulation. Experimental data should be available for simulations validation / calibration.

There is an interesting study of flywheel design optimization, including air friction:

MathLab is used as a tool for calculations, but it is quite possible you know it already.

Take care,


Hi Retsam,

Thanks for the reply. Don’t worry, “its too hard” is still a useful answer - it lets me know that I’m wasting my time trying to figure it out.

That report looks interesting, I’ll have a read through that.

I have used Matlab before, but it’s been quite a few years since I’ve used it, and never for anything particularly challenging.

Thanks for your feedback.