FIX LID CONDITION ON A BOUNDARY

Numerical methods and mathematical models of Elmer
Post Reply
Andrea_P
Posts: 176
Joined: 22 Mar 2021, 18:39
Antispam: Yes
Location: POLYTHECNIC UNIVERSITY OF TURIN

FIX LID CONDITION ON A BOUNDARY

Post by Andrea_P »

Good morning dear community,
I am not able to fix the cover of my tank as a boundary condition, namely, I would like that my fluid, which is sliding on the left wall, slides also on the cover of my tank. There are two fluids: water (on the bottom) and air (on the top). I am simulating the interface with FreeSurface solver. I attached the gif as visual explication, the case.sif and the mesh file. I really appreciate any suggestions to improve my simulation because I am new in Elmer.
Regards,
Andrea
Attachments
due_rettangoli.msh
(14.07 KiB) Downloaded 135 times
case.sif
(4.54 KiB) Downloaded 146 times
results_1_ridotta.gif
results_1_ridotta.gif (1002.61 KiB) Viewed 1810 times
POLYTECHNIC UNIVERSITY OF TURIN-DIMEAS
kevinarden
Posts: 2237
Joined: 25 Jan 2019, 01:28
Antispam: Yes

Re: FIX LID CONDITION ON A BOUNDARY

Post by kevinarden »

I would try;

Boundary Condition 4
Target Boundaries(1) = 2
Name = "Lid"
Velocity 1 = 0
Velocity 2 = 0
Mesh Update 1 = 0
Mesh Update 2 = 0
End
Andrea_P
Posts: 176
Joined: 22 Mar 2021, 18:39
Antispam: Yes
Location: POLYTHECNIC UNIVERSITY OF TURIN

Re: FIX LID CONDITION ON A BOUNDARY

Post by Andrea_P »

I have tried, unfortunately, it does not work as I want. Thanks for your answer.
Andrea
Attachments
velocità.gif
(232.9 KiB) Not downloaded yet
POLYTECHNIC UNIVERSITY OF TURIN-DIMEAS
kevinarden
Posts: 2237
Joined: 25 Jan 2019, 01:28
Antispam: Yes

Re: FIX LID CONDITION ON A BOUNDARY

Post by kevinarden »

The left wall has a boundary condition of Velocity 2 so the last side is obeying that. The top boundary being held at Velocity 2 = 0, and Velocity 1 = 0. Intersects the the left wall at the corner. So the corner node seems to have contradicting conditions. There needs to be some sort of sliding condition at the intersection.
raback
Site Admin
Posts: 4812
Joined: 22 Aug 2009, 11:57
Antispam: Yes
Location: Espoo, Finland
Contact:

Re: FIX LID CONDITION ON A BOUNDARY

Post by raback »

Hi Andrea,

Before trying to analyze the sif it would be good to know what you're trying to analyze. Is the interface between the fluid and air an internal interface?

Now the limitation of the Largrangian approach is that your free surface here needs to be a unique function of x. Then only can you map the geometry to the deformed shape. If the deformation is not mappable you need to use Eulerien techniques such as the level set method. There is no way to combine these too currenly.

As I understand your left wall draws some water with it. But the fluid cannot escape but will maintain the container. Sounds to me like this could lead to the fluid being split to tiny droplets. Maybe if you post a picture of the experiment you're trying to reproduce would help.

-Peter
Andrea_P
Posts: 176
Joined: 22 Mar 2021, 18:39
Antispam: Yes
Location: POLYTHECNIC UNIVERSITY OF TURIN

Re: FIX LID CONDITION ON A BOUNDARY

Post by Andrea_P »

Hi Peter,
Thanks for your answer. It is an internal interface, and I understood that for my case, it couldn't be useful to use the FreeSurface, but it would be better to use an eulerian approach.
Regards,
Andrea
POLYTECHNIC UNIVERSITY OF TURIN-DIMEAS
Post Reply