Visualizing flow over propeller blade with co-rotating coordinate system


#1

Hi,

Consider a rotating propeller in a fluid. The propeller is rotating in relation to a fixed coordinate system in the fluid domain.
If you freeze time and slice the propeller blade airfoil with a plane, the velocity field in that plane would look something like case on case 1, on the picture below.
If you instead have a coordinate system that is fixed in relation to the propeller blade and freeze time, you would instead see the something like on case 2.

So my question is:
How can I visualize the flow like in case 2?

I have downloaded paraview, I guess it would be good to do it in that software.


#2

Hi @Filiptheking!

I would also switch to the offline version of Paraview to transform the coordinate system because this is not possible on SimScale at the moment.

Cheers!

Jousef


#3

Hi,

Any tips regarding how to do it in Paraview?

Sincerely,
Filip


#4

Hi @Filiptheking,

I have done this before,

  • make a radius field using the calculator and coordinates
  • use radius and oposing angular velocity to calculate the counter velocity field
  • Add counter rotating field to the velocity field

This visualisation will act as if you are following the blade round as you are viewing it, therefore, anything not spinning as fast as the fan will be rotating. I therefore, suggest you clip close to the fan to ensure your view of the close proximity flow to the prop is not obscured.

Good luck,
Darren


#5

Thank you very much @1318980
I followed your instructions and it seems like I get the results I’m looking for now.

Here is what I put in to the calculator:
norm(-coordsZ * iHat+coordsX * kHat) * 419.6 * sqrt(coordsX^2+coordsZ^2)+U