[malpoli247]

Hey there,
I am modeling a raceway pond and have a question regarding the velocity/ the drive.
My model is currently a 2D Model. The best way to describe it is the attatched picture.

Now, I wonder how I model the paddlewheel best. I thought of modeling it with a UFD, because i dont think there is a appropiate boundery condition for it...

Can you guys help me ?

My thanks in advance!

[ghost82]

Hi,
Hi think the best way is modeling with VOF (air + water).
You can use MRF or mesh motion, by splitting the domain into 2 parts (rotor, enclosing the impeller and stator).
If you use MRF there's no need to use udf, just set a frame motion and input directly the rotational velocity; if you use mesh motion you can directly input the rotational velocity, but if you start your simulation with water at rest you may need to slowly increase the impeller rotational velocity till reaching the final one (you can write a DEFINE_CG_MOTION udf and increase rotational velocity linearly with time, for example, from 0 rpm till xx rpm).
If you use mesh motion you need to create interface between rotor and stator, no need to create interface with MRF.
Or you can create interface, starting with a MRF solution and then switch to mesh motion.

Daniele

PS: if you want to simulate the domain you posted in the picture you have to make a 3d simulation

[malpoli247]

Hey,
thank you for your answer. I will try as you suggested!
Sure i know that i will need 3d for the whole model, but i wanted to try the drive with a 2D model...

Now i will do it in 3D

Tank You

p.s.
if anyone ever finds this in search or google, try this tutorial for MRF
https://www.youtube.com/watch?v=P2vaj70ATZs