Floodgate need advice from more experienced users!

[wsp]

Hi!

This is a test to make realistic water flow. And I'm pretty pleased with the result.
However there are a few things i wonder how to improve.

Here is a link to the animation.
http://www.kennetjohansson.se/filmer/dam/dam.html

In the beginning, when the hatch is opening the water seem to get stuck for a short while before it really starts to flow.



Should I increase the spf? I used spf 8 here.
Change advection? Classic in this one.
Change object voxels from inscribed to something else?

How do i get the water to flow more free in the beginning?

I also get som weird water spikes in the beginning like in this picture.

What could be the cause of this?

14.5 million cells in this simulation by the way.
I'm a new user of phoenixFD and if some of you more experienced folks can give some advise it would be helpful.
3ds max 2015, phoenix fd 2.2 and vray 3.008

[Ivaylo Katev]

hi, i suppose the inscribed geometry is not the reason, because it is just one cell layer. but if the container is too long it may be really the voxel mode. can you post an image of this moment but shown in the viewport?
the second shot is definitively question of spf. your scene has very high dynamics and requires high spf. you can try to avoid it switching to ft advection + smooth conservation. this mode requires lower spf values compared to classic.

[wsp]

Ok great so a higher spf could probably remove those spikes. Here are a couple of screenshots from the viewport.



Actually, I see now that some fluids seem to pass through the floor?

[Ivaylo Katev]

the water penetrates into the geometry, is it possible to be some geometry issue? flipped normals or perhaps holes? phoenix counts a voxel for internal if there is a wall in all the directions, for example if you have a sphere with only one polygon missing or flipped, this will produce a "worm hole" through the entire sphere until the opposite surface.

[wsp]

I tried again with a new remade geometry. Could not find any flipped normals or holes in the other one either but to be sure a made a new one.
Fluids still pass through the geometry? Really weird? I made the grid cell size larger to get faster simulation times but this should not matter right?

[Ivaylo Katev]

the geometry is apparently open, switch to circumscribed mode and there will be no problem

[wsp]

I also tried to add a shell modifyer to create a closed volume.
the old one was also a closed volume.
It still passes straight through. Doing a new test with circumscribed now.

[wsp]

New test with circumscribed, still no difference.

[Ivaylo Katev]

if even circumscribed can't help, this sounds like a bug, can you send the scene for investigation?

[wsp]

hmm, i'm not really sure what I did but its working now. I cleared some old cachefiles and started fresh and its working fine. No fluids goes through the geometry even with inscribed voxel mode. Maybe it was some old simulation lurking in the background after all.

[Ivaylo Katev]

sometimes i hit a problem when the input is redirected and it looks like it simulates, but actually it reads an pld simulation. anyway, good that the problem is gone

[wsp]

I think that's the same thing that happened to me also. Thanks anyway

[TSR_trix]

sometimes i hit a problem when the input is redirected and it looks like it simulates, but actually it reads an pld simulation. anyway, good that the problem is gone

Hahaha, a penny for every time I have encountered this very same thing, I would be rich

EDIT: And the funny part comes when you redirect the input in the right place and see what you have done after tweaking the values time after time... BOOM!

[Ivaylo Katev]

EDIT: And the funny part comes when you redirect the input in the right place and see what you have done after tweaking the values time after time... BOOM!

yep, i have seen it many times perhaps some warning for this situation will be not too annoying?

[TSR_trix]

Hehee, I think I need just a whoop my a** for this

Well, pop ups are usually quite annoying but a warning for using fixed input cache could be useful. And a check box for not to mention anymore of course.
Sorry for ruining the original post!