Chimney effect

[ogdgs]

Hi

I’m trying to recreate the effect of a fire drawing up a chimney. Once the fire gets going the fire should be “sucked” up the chimney. Please see:

https://n1.fileflow.com:443/fileflow/do ... uOS&type=1

as you can see there is no difference when the chimney is present.

Is this a limitation of the software? I believe this effect would require the pressure in the chimney to drop below atmospheric pressure. Is this possible in FumeFX?

thanks

OLIVER GUEST

[Capitanred]

any improvement on this? maybe use more expansion, and close the chimney bottom. so nothing can go downwards.

[Bandu]

I would say it is a temperature issue...
Think what happend in real life with fuel, oxygen, heat, air stream...

"as you can see there is no difference when the chimney is present."

...because it is "only" a collision object that smoke reacts to, but there is no reaction back from your chimney.

Bandu

[ogdgs]

See:

http://en.wikipedia.org/wiki/Chimney

scroll down to: "Chimney draught or draft"

I’m pretty sure its a pressure issue. Could we have a confirmation from developers that FumeFX will, or will not, simulate pressures below atmospheric?

thanks

Oliver

[Bandu]

"I’m pretty sure its a pressure issue. Could we have a confirmation from developers that FumeFX will, or will not, simulate pressures below atmospheric?"

I think there is nothing like pressure in FFX, or not one like we know it.
If you look at this small test,
http://www.b3d-animations.com/ffx/ffx_tmp.avi
there is a small hole in the cube at the bottom face, where the smoke should be pressed out, nothing like this heppend

cheers,
Bandu

[ogdgs]

Hi

Is the hole smaller than the voxel size? If it is then it wouldn’t work anyway…

However, I’m not sure it can rightfully be called a fluid dynamics simulator if there is no pressure simulation….?

Thanks

Oliver

[Bandu]

[ogdgs]

yeh i think its fair to assume there is no pressure simulation then

[Bandu]

hock: hock:
CORRECTION!

it works much better if Expansion is greater than one...

my mistake :lol: