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Author Topic: Basic Questions  (Read 2772 times)

Hidymester

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Basic Questions
« on: February 07, 2014, 03:59:26 am »

Hi,

I'm a new user of Pyrosim and I have some basic question.

There are three screenshots in the attachment:

- on the 1st pic the cell size ratio at x and y cells are not correct, will this affect the outcome or just impairs the stability of the simulation?

- on the 2nd pic the obstructions are not alligned to the bourders of the cells. Is it allowed or will this affect the outcome?

- on the 3rd pic a device (ESFR sprinkler head) is positioned inside of a cell. Is it allowed or has to be positioned to a cell border or cell "corner"?

Thank you!
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Charlie Thornton

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Re: Basic Questions
« Reply #1 on: February 07, 2014, 10:21:16 am »

1. The general thinking is that more cube-like cells (size ratio = 1.0) are "better". I think that you start to get a greater chance of numerical artifacts or instability errors the farther away the cells are from cubes.

2. There are two different actors (PyroSim, and FDS) and two different cases (aligned blocks and all other geometry).

For aligned blocks, PyroSim will write the geometry to the FDS input file exactly as it has been specified. FDS will then fit the geometry to the mesh by adjusting the bounds of the geometry to hit the cell divisions.

For all other geometry, PyroSim converts it to aligned blocks when it writes the FDS input file. PyroSim uses the meshes to figure out how to do this and the geometry it writes to the FDS file will be what you get when FDS runs. It tends to look like a blocky version of what you see in PyroSim. You can click toolbar button Preview FDS Blocks to see what it will look like.

3. I've never actually thought about the relationship between particles and cells. I think they are mesh independent but I don't know for sure. I use sprinklers like it doesn't matter where they hit on the mesh.
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Hidymester

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Re: Basic Questions
« Reply #2 on: February 10, 2014, 02:57:33 am »

1. The general thinking is that more cube-like cells (size ratio = 1.0) are "better". I think that you start to get a greater chance of numerical artifacts or instability errors the farther away the cells are from cubes.

2. There are two different actors (PyroSim, and FDS) and two different cases (aligned blocks and all other geometry).

For aligned blocks, PyroSim will write the geometry to the FDS input file exactly as it has been specified. FDS will then fit the geometry to the mesh by adjusting the bounds of the geometry to hit the cell divisions.

For all other geometry, PyroSim converts it to aligned blocks when it writes the FDS input file. PyroSim uses the meshes to figure out how to do this and the geometry it writes to the FDS file will be what you get when FDS runs. It tends to look like a blocky version of what you see in PyroSim. You can click toolbar button Preview FDS Blocks to see what it will look like.

3. I've never actually thought about the relationship between particles and cells. I think they are mesh independent but I don't know for sure. I use sprinklers like it doesn't matter where they hit on the mesh.

Thank You for the answers!
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Hidymester

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Re: Basic Questions
« Reply #3 on: February 13, 2014, 04:22:11 am »

Hi,

Does Your company operates the "www.pyrosim.eu" webpage?
I was wondering about a training course and there is an offer on this page. If this page is not connected to You, is there any "official" training course in Europe?

Regards
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Charlie Thornton

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Re: Basic Questions
« Reply #4 on: February 13, 2014, 10:57:48 am »

That webpage is operated by one of our affiliates in the Belgium and Luxembourg area. I know that they have offered training services in the past. The contact information is:

Aeolus Consulting
Lemersveld 23
2440 Geel
BELGIUM

Tel: +32 (0) 496/10.94.63
Fax: +32 (0) 14/58.77.53
Email: info@aeolus-consulting.be
Web: http://www.aeolus-consulting.be


There are a few other resellers operating in Europe. I think all of them offer training services. You can find the full list in the International Distributors section of our Licensing page.
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