LEVEL SET WITH A STARTING VELOCITY PROFILE

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

LEVEL SET WITH A STARTING VELOCITY PROFILE

Post by Andrea_P »

Hi,
I am trying to obtain the same velocity profile already computed; I know the starting velocity profile and the boundary conditions, nevertheless I didn't obtain the same profile even if the mesh is refined. I attached everything in the .zip with the used parameters, there isn't a pressure gradient and the profile is stable in time. Thanks in advance for your help.
Regards,
Andrea
Attachments
OSCILLAZIONI.zip
(54.92 KiB) Downloaded 119 times
mesh.geo
(796 Bytes) Downloaded 115 times
case.sif
(4.63 KiB) Downloaded 119 times
POLYTECHNIC UNIVERSITY OF TURIN-DIMEAS
kevinarden
Posts: 2237
Joined: 25 Jan 2019, 01:28
Antispam: Yes

Re: LEVEL SET WITH A STARTING VELOCITY PROFILE

Post by kevinarden »

Your mesh is a tall narrow square. With boundaries as labeled in the picture. You are defining a vertical velocity (velocity 2) on wall 4 as a function of Variable Coordinate 1 (which is X). Therefor X is a constant value of 0.00302.

Real MATC "if (tx<=h) -0.5*g*tx^2/nuPlus + g*h*tx/nuPlus -Up; else 0;"

$ h = 4.27e-5
sets h to that value, in your MATC equation tx (equals 0.00302) is always more than h, since they are both constant
therefore velocity 2 is always set to 0
Is this the intent?
Attachments
problem.png
problem.png (16.9 KiB) Viewed 1821 times
Andrea_P
Posts: 176
Joined: 22 Mar 2021, 18:39
Antispam: Yes
Location: POLYTHECNIC UNIVERSITY OF TURIN

Re: LEVEL SET WITH A STARTING VELOCITY PROFILE

Post by Andrea_P »

kevinarden wrote: 28 May 2021, 23:28 Your mesh is a tall narrow square. With boundaries as labeled in the picture. You are defining a vertical velocity (velocity 2) on wall 4 as a function of Variable Coordinate 1 (which is X). Therefor X is a constant value of 0.00302.

Real MATC "if (tx<=h) -0.5*g*tx^2/nuPlus + g*h*tx/nuPlus -Up; else 0;"

$ h = 4.27e-5
sets h to that value, in your MATC equation tx (equals 0.00302) is always more than h, since they are both constant
therefore velocity 2 is always set to 0
Is this the intent?
Hi Kevin,
The intent is that the velocity profile expressed in MATC was computed only between 0 and h, because at length h there is the zinc-air interface.
Regards,
Andrea
POLYTECHNIC UNIVERSITY OF TURIN-DIMEAS
kevinarden
Posts: 2237
Joined: 25 Jan 2019, 01:28
Antispam: Yes

Re: LEVEL SET WITH A STARTING VELOCITY PROFILE

Post by kevinarden »

If h is the height of the interface than you would have
Velocity 2 = Variable Coordinate 2
since direction 2 is the height
Andrea_P
Posts: 176
Joined: 22 Mar 2021, 18:39
Antispam: Yes
Location: POLYTHECNIC UNIVERSITY OF TURIN

Re: LEVEL SET WITH A STARTING VELOCITY PROFILE

Post by Andrea_P »

kevinarden wrote: 29 May 2021, 13:53 If h is the height of the interface than you would have
Velocity 2 = Variable Coordinate 2
since direction 2 is the height
Hi,
I share the axes position and the h length. So, I want that the velocity profile is computed for each coordinate x value up to h.
-Andrea
Attachments
problem.jpg
problem.jpg (850.25 KiB) Viewed 1807 times
POLYTECHNIC UNIVERSITY OF TURIN-DIMEAS
kevinarden
Posts: 2237
Joined: 25 Jan 2019, 01:28
Antispam: Yes

Re: LEVEL SET WITH A STARTING VELOCITY PROFILE

Post by kevinarden »

Then the target boundary should be 1 not 4.
Andrea_P
Posts: 176
Joined: 22 Mar 2021, 18:39
Antispam: Yes
Location: POLYTHECNIC UNIVERSITY OF TURIN

Re: LEVEL SET WITH A STARTING VELOCITY PROFILE

Post by Andrea_P »

kevinarden wrote: 29 May 2021, 15:11 Then the target boundary should be 1 not 4.
Actually, I have already checked and it is 4 the right one .
Attachments
mesh.jpg
(59.49 KiB) Not downloaded yet
POLYTECHNIC UNIVERSITY OF TURIN-DIMEAS
kevinarden
Posts: 2237
Joined: 25 Jan 2019, 01:28
Antispam: Yes

Re: LEVEL SET WITH A STARTING VELOCITY PROFILE

Post by kevinarden »

Sorry that does not appear to be the way the posted geo file is written. i did not know the boundaries were renumbered when converted to Elmer mesh.
Andrea_P
Posts: 176
Joined: 22 Mar 2021, 18:39
Antispam: Yes
Location: POLYTHECNIC UNIVERSITY OF TURIN

Re: LEVEL SET WITH A STARTING VELOCITY PROFILE

Post by Andrea_P »

kevinarden wrote: 29 May 2021, 17:38 Sorry that does not appear to be the way the posted geo file is written. i did not know the boundaries were renumbered when converted to Elmer mesh.
Hi,
I have uploaded the right mesh in the following link: https://file.io/POv24JDkIbwq. I am sorry for my misunderstanding.
Regards,
Andrea
Attachments
problem.jpg
problem.jpg (854.87 KiB) Viewed 1798 times
POLYTECHNIC UNIVERSITY OF TURIN-DIMEAS
kevinarden
Posts: 2237
Joined: 25 Jan 2019, 01:28
Antispam: Yes

Re: LEVEL SET WITH A STARTING VELOCITY PROFILE

Post by kevinarden »

The link just says the file has been deleted.
Post Reply