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Chimney effect - Printable Version

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+--- Thread: Chimney effect (/showthread.php?tid=618)



Chimney effect - ogdgs - 06-09-2008

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


Re: Chimney effect - Capitanred - 06-10-2008

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


Re: Chimney effect - Bandu - 06-11-2008

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


Re: Chimney effect - ogdgs - 06-11-2008

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


Re: Chimney effect - Bandu - 06-11-2008

"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


Re: Chimney effect - ogdgs - 06-11-2008

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


Re: Chimney effect - Bandu - 06-11-2008

[Image: ffx_tmp.jpg]


Re: Chimney effect - ogdgs - 06-11-2008

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


Re: Chimney effect - Bandu - 06-11-2008

Confusedhock: Confusedhock:
CORRECTION!

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

my mistake :lol: