interFoam channel hull parasitic currents?
 

Hi Foamers,

this is my first post and i'm not sure if it is at the right place... and not so good in writing englisch... But my problem is:

I use interFoam with OpenFoam 2.3. The case is a wind tunnel with two phases and a geometrie inside. Boundary conditions and all other settings are like the tutorial DTCHull in interDyMFoam but without moving mesh. There are only some changes at the velocity. It starts with 0 m/s and then speed up with 0.3m/s² for the whole area.

The result shows, everywhere where the grid split into smaller cells are non-physical velocities near the surface in the air phase. The picture shows a sitution like this. This is the result after 0.1 seconds. So the velocity should be 0.03m/s.

Is here anybody who knows what I did wrong or are these parasitic currents? Is there a trick to handle this problem?

I changed a little bit the interFoam solver after seeing these results. But only at the pEqn.H like some people wrote here in the Forum for parasitic currents (Brackbill or Raeini). But I didn't test the complete code of Raeini. This changing had no effect.


Greetings,
Mock

Greetings Mock and welcome to the forum!

It looks to me that the mesh transition is in a very bad place. Have a look into this blog post of mine, so that you can get a better idea on how important the mesh is, specially "Case two": OpenFOAM: Interesting cases of bad meshes and bad initial conditions

Best regards,
Bruno

Hi, do you see these spikes at interphases?

Regards.

Hi santiagomarquezd,

these spikes are at the air-phase. Maybe a these pictures show it better:

Attachment 32928

Attachment 32929

The red oval shows the location from the upper part of the picture (xz-plane).

Best regards,

Mock

As Bruno said, probably mesh problems.

Regards.