thin obstruction
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szilagyics
May 18, 2008, 5:24:04 PM5/18/08
to FDS and Smokeview Discussions
Hello,
I would like to use a thin obstruction. It's thinner than one mesh
cell. It's a wood sheet and I would like to burn it. In SURF ID I
added its thickness, and it seems to work well. But I have noticed an
interesting part in 38 page in User's Guide:
A thin sheet obstruction can only have one velocity vector on its
face, thus a gas cannot be injected reliably from a thin obstruction
because whatever is pushed from one side is necessarily pulled from
the other.
I don't know what means it? It means that when burning gas discharge
from my material. Or It means that one gas is injected from this
material (like a VENT) ?
Thank you for your attention
Csaba
I would like to use a thin obstruction. It's thinner than one mesh
cell. It's a wood sheet and I would like to burn it. In SURF ID I
added its thickness, and it seems to work well. But I have noticed an
interesting part in 38 page in User's Guide:
A thin sheet obstruction can only have one velocity vector on its
face, thus a gas cannot be injected reliably from a thin obstruction
because whatever is pushed from one side is necessarily pulled from
the other.
I don't know what means it? It means that when burning gas discharge
from my material. Or It means that one gas is injected from this
material (like a VENT) ?
Thank you for your attention
Csaba
Kevin
May 19, 2008, 8:54:40 AM5/19/08
to FDS and Smokeview Discussions
It means that the components of velocity, u, v and w, are defined at
the respective cell faces. A thin obstruction shares the same
component of velocity on each side. The mass flux of fuel is a
combination of convection and diffusion. The point of the warning in
the Guide is that the convection part, because it involves the normal
component of velocity, cannot be trusted. I suggest you do not use a
thin, flammable obstruction.
the respective cell faces. A thin obstruction shares the same
component of velocity on each side. The mass flux of fuel is a
combination of convection and diffusion. The point of the warning in
the Guide is that the convection part, because it involves the normal
component of velocity, cannot be trusted. I suggest you do not use a
thin, flammable obstruction.
szilagyi csaba
May 19, 2008, 12:47:12 PM5/19/08
to fds...@googlegroups.com
Thank you.
Is it sounds better, if I use one mesh cell thick in OBST line, and I
use half of thick in the THICKNESS line in SURF ID line. I know in the
Render my material won't be good, but I hope it will be good in the
calculation. Sorry If I'm too obstinate, but It's very interesting
for me.
Is it sounds better, if I use one mesh cell thick in OBST line, and I
use half of thick in the THICKNESS line in SURF ID line. I know in the
Render my material won't be good, but I hope it will be good in the
calculation. Sorry If I'm too obstinate, but It's very interesting
for me.
Csaba
2008/5/19, Kevin <mcgr...@gmail.com>:
--
Szilágyi Csaba
Hungary
5000 Szolnok
Baross G. utca/street 41. C. I./1.
Tel:+36-70-3748812
email: csaba.s...@gmail.com
Kevin
May 19, 2008, 1:38:56 PM5/19/08
to FDS and Smokeview Discussions
The THICKNESS should be the actual thickness of the object.
On May 19, 12:47 pm, "szilagyi csaba" <csaba.szila...@gmail.com>
wrote:
> email: csaba.szila...@gmail.com- Hide quoted text -
>
> - Show quoted text -
On May 19, 12:47 pm, "szilagyi csaba" <csaba.szila...@gmail.com>
wrote:
> Thank you.
> Is it sounds better, if I use one mesh cell thick in OBST line, and I
> use half of thick in the THICKNESS line in SURF ID line. I know in the
> Render my material won't be good, but I hope it will be good in the
> calculation. Sorry If I'm too obstinate, but It's very interesting
> for me.
>
> Csaba
>
> 2008/5/19, Kevin <mcgra...@gmail.com>:
> Is it sounds better, if I use one mesh cell thick in OBST line, and I
> use half of thick in the THICKNESS line in SURF ID line. I know in the
> Render my material won't be good, but I hope it will be good in the
> calculation. Sorry If I'm too obstinate, but It's very interesting
> for me.
>
> Csaba
>
>
> - Show quoted text -
Pin
May 20, 2008, 11:18:49 AM5/20/08
to FDS and Smokeview Discussions
When creating an obstruction, we have to set the dimension in x, y and
z. Is it already included the thickness of the object? If I set the
difference between XYZ and the thickness of the object, what result
will be obtained?
z. Is it already included the thickness of the object? If I set the
difference between XYZ and the thickness of the object, what result
will be obtained?
Kevin
May 20, 2008, 11:28:56 AM5/20/08
to FDS and Smokeview Discussions
The THICKNESS on the SURF line is independent of the OBST dimensions.
Please read the User's Guide for more details.
> > > - Show quoted text -- Hide quoted text -
Please read the User's Guide for more details.
Pin
May 20, 2008, 12:09:10 PM5/20/08
to FDS and Smokeview Discussions
I have read through the user guide before. I can't find any idea.
For example, i would to create an object with dimension 1m x 1m x 1m.
It should be created an solid object. If I define the thickness on the
surf line, say 200mm, will a hollow object be created?
For example, i would to create an object with dimension 1m x 1m x 1m.
It should be created an solid object. If I define the thickness on the
surf line, say 200mm, will a hollow object be created?
Kevin
May 20, 2008, 12:33:27 PM5/20/08
to FDS and Smokeview Discussions
Search this Group for the word THICKNESS
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