Streamlines vs moving reference frame

Lucky Luka · June 21, 2019, 06:40

Hi all
I have 3 regions in my axial fan simulation model.
I used a moving reference plane for my rotating fan. Air is represented in the region of the fan (the middle region of the 3 present).

I don't like the way streamlines appear in the fan region though.
I've been told that there is a way to solve this issue but I don't know how to do that.
Can anyone help me?
Cheers

fluid23 · June 21, 2019, 09:54

You will have to be more specific about what you want to change.

Lucky Luka · June 21, 2019, 10:04

Quote:

Originally Posted by fluid23

You will have to be more specific about what you want to change.

Hi
I just want to see streamlines inside the fan.
The ones that are present right now are those one of the two adjacent regions.

Is it possible?
Cheers

fluid23 · June 21, 2019, 10:06

Perhaps I misunderstand, but I see streamlines inside the fan region. Are they not what you expected?

fluid23 · June 21, 2019, 10:07

Can you take a screencapture of your derived parts setup? (prtscn would be prefered over a photo, btw.)

Lucky Luka · June 21, 2019, 10:08

Quote:

Originally Posted by fluid23

Perhaps I misunderstand, but I see streamlines inside the fan region. Are they not what you expected?

I expected to see them more in circles than what I got.
I thought it was due to the moving reference frame solution I used for the fan the fact that they barely develop inside the fan region.

fluid23 · June 21, 2019, 10:14

I would expect to see them change direction, but not necessarily swirl around within the fan region. The streamlines coming out of the back have obvious swirl.

Now that being said, you know what you are modeling better than I. If you have another reference or something you are comparing to that is similar and shows this behavior, then there might be something that needs to change.

fluid23 · June 21, 2019, 10:27

It does look like not all your streamlines are showing up on the other side. You might try adjusting the max propagation/steps in derived part > streamline> integrator.

JBeilke · June 26, 2019, 08:51

The trick is to create a new vector field function for the velocity which takes the absolure velocity in the fixed region and the relative velocity for the impeller.

June 21, 2019, 10:27		#8
fluid23 Senior Member Matt Join Date: Aug 2014 Posts: 947 Rep Power: 17	It does look like not all your streamlines are showing up on the other side. You might try adjusting the max propagation/steps in derived part > streamline> integrator. Lucky Luka likes this.

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June 21, 2019, 09:54		#2
fluid23 Senior Member Matt Join Date: Aug 2014 Posts: 947 Rep Power: 17	You will have to be more specific about what you want to change.

June 21, 2019, 10:06		#4
fluid23 Senior Member Matt Join Date: Aug 2014 Posts: 947 Rep Power: 17	Perhaps I misunderstand, but I see streamlines inside the fan region. Are they not what you expected?

June 21, 2019, 10:07		#5
fluid23 Senior Member Matt Join Date: Aug 2014 Posts: 947 Rep Power: 17	Can you take a screencapture of your derived parts setup? (prtscn would be prefered over a photo, btw.)

June 21, 2019, 10:14		#7
fluid23 Senior Member Matt Join Date: Aug 2014 Posts: 947 Rep Power: 17	I would expect to see them change direction, but not necessarily swirl around within the fan region. The streamlines coming out of the back have obvious swirl. Now that being said, you know what you are modeling better than I. If you have another reference or something you are comparing to that is similar and shows this behavior, then there might be something that needs to change.

June 26, 2019, 08:51		#9
JBeilke Senior Member Joern Beilke Join Date: Mar 2009 Location: Dresden Posts: 498 Rep Power: 20	The trick is to create a new vector field function for the velocity which takes the absolure velocity in the fixed region and the relative velocity for the impeller.