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-   -   Problem to visualise baffles (http://www.cfd-online.com/Forums/flow-3d/89861-problem-visualise-baffles.html)

quemmo June 24, 2011 03:02

Problem to visualise baffles
 
Hi, i am a new user of flow3d, i use flow3d version 9.4
i have got problem to visualise baffles. i can't see them after i ran the simulation. I changed the transparancy, but nothing. Moreover, no baffles appear in the object list in the display tab. Thanks for answering!

MuxaB June 27, 2011 19:50

Quote:

Originally Posted by quemmo (Post 313361)
Hi, i am a new user of flow3d, i use flow3d version 9.4
i have got problem to visualise baffles. i can't see them after i ran the simulation. I changed the transparancy, but nothing. Moreover, no baffles appear in the object list in the display tab. Thanks for answering!

You should be able to see them after importing the baffles using the Tools menu in Display.

quemmo June 28, 2011 05:03

I already tried, but no baffles files appear. I only can see my simulation file, and when i open it, i only see the temp file. Yet i created a baffle in the mesh and geometry tab. The baffle is defined as a flux surface. Is that why i can visualise it?
Here is the part of the prepin file that defines the baffle, maybe i did something wrong :
$bf
nbafs=1, bx(1)=2.922, by(1)=7.0295e-1, bz(1)=4.8005e-1,
bra(1)=0.067,
ifbaf(1)=1,
btrnx(1)=2.922, btrny(1)=7.0295e-1, btrnz(1)=4.8005e-1, pbaf(1)=1.,
brotx(1)=29.31, broty(1)=0., brotz(1)=52.07,
$end

thanks for answering

MuxaB June 29, 2011 20:12

Quote:

Originally Posted by quemmo (Post 313852)
I already tried, but no baffles files appear. I only can see my simulation file, and when i open it, i only see the temp file. Yet i created a baffle in the mesh and geometry tab. The baffle is defined as a flux surface. Is that why i can visualise it?
Here is the part of the prepin file that defines the baffle, maybe i did something wrong :
$bf
nbafs=1, bx(1)=2.922, by(1)=7.0295e-1, bz(1)=4.8005e-1,
bra(1)=0.067,
ifbaf(1)=1,
btrnx(1)=2.922, btrny(1)=7.0295e-1, btrnz(1)=4.8005e-1, pbaf(1)=1.,
brotx(1)=29.31, broty(1)=0., brotz(1)=52.07,
$end

thanks for answering

Flux surface or not does not matter. Baffles should always be shown on 2D plots as lines. See if you can see it there.

Also, when defining baffles you only need bx, by or bz, but not all of them. For exmaple, bx(1)=2.922 defines a baffle as a x=2.922 surface. Same applied to by and bz. Having all of them defined makes no sense and may result in no baffle.

quemmo June 30, 2011 10:57

OK, I will try again, by keeping only bz.

I was wondering if there was a quick way to visualise baffles before running the simulation.

thanks

quemmo July 1, 2011 03:16

I tried, but nothing !!!
Still no baffles in object list in the display tab, no baffles in 2D plots. I can't imort any baffles.
Obviously, I don't understand how to create a baffle !
In fact i want to create flux surface as a disk, which radius is R and the center is in x=a, y=b, z=c (for example). Moreover, knowing the normal of the surface, i have to incline it. So here is the new part of the prepin that defines the baffle :
$bf
nbafs=1, bz(1)=4.8005e-1,
bra(1)=0.067,
ifbaf(1)=1,
btrnx(1)=2.922, btrny(1)=7.0295e-1, pbaf(1)=1.,
brotx(1)=29.31, broty(1)=0., brotz(1)=52.07,
$end
To define the baffle as disk surface, i only enter the disk radius in "cylindrical radius". I enter nothing in "cylindrical angle", "spherical radius", "cone angle".

hoping you can solve my problem!
thanks

MuxaB July 1, 2011 17:48

Quote:

Originally Posted by quemmo (Post 314341)
I tried, but nothing !!!
Still no baffles in object list in the display tab, no baffles in 2D plots. I can't imort any baffles.
Obviously, I don't understand how to create a baffle !
In fact i want to create flux surface as a disk, which radius is R and the center is in x=a, y=b, z=c (for example). Moreover, knowing the normal of the surface, i have to incline it. So here is the new part of the prepin that defines the baffle :
$bf
nbafs=1, bz(1)=4.8005e-1,
bra(1)=0.067,
ifbaf(1)=1,
btrnx(1)=2.922, btrny(1)=7.0295e-1, pbaf(1)=1.,
brotx(1)=29.31, broty(1)=0., brotz(1)=52.07,
$end
To define the baffle as disk surface, i only enter the disk radius in "cylindrical radius". I enter nothing in "cylindrical angle", "spherical radius", "cone angle".

hoping you can solve my problem!
thanks

You are getting there! You need to change 'BRA' to 'BRAH'. BRA defines a cylindrical baffle at R=BRA, while BRAH limits the baffle extent to R<BRAH. Sorry, i did not notice this error yesterday.

Then run the pre-processor and load the file prpgrf into analyze. You should be able to see the baffle on 2d and 3d plots. You can also lok at the plots in the prpplt file created by the pre-processor. Open it in Analyze as Existing results file.

quemmo July 4, 2011 05:38

I change BRA into BRAH, and pre-process the simulation, but nothing. For example when i select baffles options in view in the display tab, there is no baffle in the baffle index. Is that not weird? Was the rest of the prepin correct?

Concerning the Model SetUp tab :
Do I have to enter values in cylindrical angle low/hight (0-360)?
Does bz(1) only define the plan of construction of the baffle?
Do i have to select particular outputs?

thanks

JBurnham July 5, 2011 14:47

Try going to the Analyze tab, loading the prpgrf preprocessed results file, and then select 'Units': set the plot units to be the same as the results units. If that fixes your problem, consider upgrading to v9.4.5, in which that issue has been fixed to work automatically for baffles.

quemmo July 6, 2011 04:07

I can't access to the result units when i go in Units, it is grey colored. I can only change the plot units. I modify them to be the same as the result units, but nothing. No baffle appears... Yet i have created one in the meshing & geometry tab. Why doesn't the baffle appear in the baffle index in baffle options in the display tab?

Can you send to me the prepin of a simple example which includes baffle please?

thanks

quemmo July 7, 2011 08:19

Hi, i solved my problem, i manage to visualise my baffle. Here is the part of the prepin if you are interested !
$bf
nbafs=1, bz(1)=0.,
brah(1)=0.067,
ifbaf(1)=1,
btrnx(1)=2.922, btrny(1)=7.0295e-1, pbaf(1)=1.,
brotx(1)=-29.31, broty(1)=0., brotz(1)=52.07,
btrnz(1)=4.8005e-1,
$end

But i was wondering how can i get the data computed at the flux surface, for example the number of particule crossing it, the flow rate.

Thanks for answering

MuxaB July 7, 2011 11:22

So you define it first at z=0, rotate, then move it to the right position, rather than place it there from the starty, right? Nice work!

You now know that the rotations of a baffle, or any other geometric object in FLOW-3D, takes place around (0,0,0) point, so if you put something at z=1000. and rotate it 5 degrees it will end up very far from where it started. It should instead be placed at z=0, rotated, then moved to z=1000.


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