2D airfoil-- Problem with Boundary conditions

fluenter2015 · May 27, 2016, 11:17

Hi everyone:

I am simulating air flow over an airfoil.
Most of the tutorials use a "top-down approach, where you create one simple geometry for the whole domain in the first place and then splits it into smaller blocks" (from one to four in my case)

However, this method didn't worked in my case. Therefore, I used a second option known as bottom-up approach, where you create a separate sketch for each of the four blocks you want to have in the end.

Bottom up-approach worked. However, when I define boundary conditions, the edges which contact the 4 surfaces (you can see them in the end link that I attach) are defined as "wall" and I can´t change them to "interior".

Is there any solution? Any idea on how on how to solve this problem?

I really appreciate any help you can provide, I am very frustrated.

Here, you can see my mesh:

And these are tree parameters:

*In named selections, "interior" is defined by four separated faces.

Finally, here You can see the boundary conditions:

fluenter2015 · June 13, 2016, 03:45

Anyone? I really appreciate any comment

redordead · June 13, 2016, 06:46

Isnt part4 surface body actually just the surface of the airfoil ?? Have you checked that ?

diamondx · June 13, 2016, 09:43

I am no professional of Ansys meshing. What I would suspect is you don"t have adjacent element. maybe there is a small gap ??

fluenter2015 · June 20, 2016, 13:38

Quote:

Originally Posted by diamondx

I am no professional of Ansys meshing. What I would suspect is you don"t have adjacent element. maybe there is a small gap ??

I have checked the geometry, specially the most problematic area, contact between air and the airfoil and I don't detect any gap. I think that if there was any gap, Meshing would not work, althougth I am no sure.
I attach this capture where you can see this zone.

Many thanks for your tip.

fluenter2015 · June 28, 2016, 05:10

No other suggestions? I don't get a solution...

user01 · June 29, 2016, 05:06

Quote:

Originally Posted by fluenter2015

No other suggestions? I don't get a solution...

I did some simulations last year and my advice is to generate a geometry with the hole of the airfoil like in the picture below. There are some tutorials in YouTube, follow it and you will get the solution fast.

Regards.

user01 · June 29, 2016, 05:09

Quote:

Originally Posted by user01

I did some simulations last year and my advice is to generate a geometry with the hole of the airfoil like in the picture below. There are some tutorials in YouTube, follow it and you will get the solution fast.

Regards.

The image.

Far · July 1, 2016, 04:19

do not define any boundary condition there. And also make sure that should be only one edge between two surface.

fluenter2015 · June 20, 2016, 12:34

Quote:

Originally Posted by redordead

Isnt part4 surface body actually just the surface of the airfoil ?? Have you checked that ?

Hi!Thanks for your reply. The Aifoil is enclosed for the four surfaces, I have not established a surface for the airfoil. Airfoil's edge is defined as a named selection (blade).

May 27, 2016, 11:17	2D airfoil-- Problem with Boundary conditions	#1
fluenter2015 New Member J SB Join Date: Aug 2015 Posts: 6 Rep Power: 10	Hi everyone: I am simulating air flow over an airfoil. Most of the tutorials use a "top-down approach, where you create one simple geometry for the whole domain in the first place and then splits it into smaller blocks" (from one to four in my case) However, this method didn't worked in my case. Therefore, I used a second option known as bottom-up approach, where you create a separate sketch for each of the four blocks you want to have in the end. Bottom up-approach worked. However, when I define boundary conditions, the edges which contact the 4 surfaces (you can see them in the end link that I attach) are defined as "wall" and I can´t change them to "interior". Is there any solution? Any idea on how on how to solve this problem? I really appreciate any help you can provide, I am very frustrated. Here, you can see my mesh: And these are tree parameters: *In named selections, "interior" is defined by four separated faces. Finally, here You can see the boundary conditions:

June 13, 2016, 09:43		#4
diamondx Super Moderator Ghazlani M. Ali Join Date: May 2011 Location: Tokyo, Japan Posts: 1,385 Blog Entries: 23 Rep Power: 29	I am no professional of Ansys meshing. What I would suspect is you don"t have adjacent element. maybe there is a small gap ?? __________________ Regards, New to ICEM CFD, try this document --> https://goo.gl/KAOIwm Ali

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June 13, 2016, 03:45		#2
fluenter2015 New Member J SB Join Date: Aug 2015 Posts: 6 Rep Power: 10	Anyone? I really appreciate any comment

June 13, 2016, 06:46		#3
redordead New Member SAA Join Date: Sep 2015 Posts: 12 Rep Power: 10	Isnt part4 surface body actually just the surface of the airfoil ?? Have you checked that ?

June 28, 2016, 05:10		#6
fluenter2015 New Member J SB Join Date: Aug 2015 Posts: 6 Rep Power: 10	No other suggestions? I don't get a solution...

July 1, 2016, 04:19		#9
Far Super Moderator Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,553 Blog Entries: 6 Rep Power: 54	do not define any boundary condition there. And also make sure that should be only one edge between two surface.