Learning Forum

[Nicola Menga]

Hello everyone.
I'm trying to perform a fluent analysis about an oscillating airfoil (I want to obtain the hysteresis loop of cl).
In this video, the user create a circular zone around the airfoil and put it in rotation in the Cell zone conditions/Mesh motion section, by indicating a constant angular velocity.
However, I want to rotate my airfoil in an oscillating manner (like a sinusoidal motion between a minimum and a maximum angle of attack), by indicating a variable angular velocity, function of time.

It is possible to create a UDF function that assign the desired angular velocity to the circular mesh zone?

By searching on the internet, I found two different macros, i.e. DEFINE_CG_MOTION and DEFINE_GRID_MOTION but I am a bit confused about how these macros work.

There are the DEFINE_CG_MOTION and DEFINE_GRID_MOTION macros suitable for this case?

I hope I was clear.

Thank you.

 

Nicola Menga.

[Rob]

If you change the fixed rotational speed for an expression I don't think you need the other functions. 

[Nicola Menga]

Oh.
Thank you for your suggestion. I'm new to these type of problems. Maybe it's easier than I thought.

I will try.

Thank youRob. 👍

[Rob]

You're welcome. Everything is easy if you know how to do it. It's when you need to adjust the position because of the flow that you'll need some of the moving mesh macros.