[Lorena2fdez]

Hello everybody,

I have been working on the tutorial:
tutorials/lagrangian/reactingParcelFilmFoam/rivuletPanel

I tried to do different probes using the same solver but I didn't obtain rivulets except if the film is totally vertical. Finally, I found the difference between my examples an the tutorial case and this results be the position of the zone "filmWalls". In my probes the "filmWalls" is placed "down" and in the tutorial is localised "up". For a better explanation see the next figure:

RivuletPanel_MeshTutMedFilmzAngle24_UpDownScheme.png

With their respective results on the wallFilmRegion (Film zone):

RivuletPanel_MeshTutMedFilmzAngle24_ZoneFilm.png

I looked in the code the point that make some different results between two cases. At last I concluded that the biggest difference is in the term "pp". "pp" represents in the code the hydrostatic pressure of the film:
- rho (density) * min ( ( g (gravity) , n (normal vector) ) , 0 (zero vector) )
{ later it's multiplied by delta (film thickness) }

In the tutorial case, "pp" is zero ( because (g,n) < 0 ), however the film "down" example has a "pp" non zero value (this correspond to the component z of g multiplied by rho). I think that is no correct the tutorial case because it doesn't consider the hydrostatic pressure. But the solution would have rivulets like the tutorial.

Does anybody know something about this subject?

Thank you in advance!
Lorena

[wyldckat]

Greetings Lorena,

Sorry for the late answer, but I've come to this thread of yours due to a PM I received from you on May 31st, 2016.

I've read your post and I have to ask: Didn't we talk about this last year, at the Iberian Meeting of OpenFOAM tech Users in Coimbra (Portugal) in 2017?

If I remember correctly, the conclusion of the discussion we had last year was that this particular piece of code:

- rho (density) * min ( ( g (gravity) , n (normal vector) ) , 0 (zero vector) )

is ensuring that the top patch does not allow fluid to go through it. In other words, it's acting as the counter-force to the gravity, since there is a wall on top that does not allow the fluid to go through it.

Best regards,
Bruno