Primary Dendrite Arms spacing (PDAS) prediction

dendritic solidification, eutectics, peritectics,....
Bernd
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Re: Primary Dendrite Arms spacing (PDAS) prediction

Postby Bernd » Tue Oct 10, 2017 11:29 am

Hi Chamara,

it is difficult to say what is the reason for that. Obviously, you use moving frame, and each time one row of cells is moving out at the bottom of the domain, it is appended to the file NiCrFeNb_PDAS_Try25G.korn because you specified "out_Moving_Frame". When appending to this file, it has first to be opened, and this is what fails.
I could imagine that it is one of those:
- the file got too large to be opened
- another process / MICRESS job is accessing the file simultaneously
- your MICRESS job has no permission to open the file

As you say the file is very large, I would guess this could be the reason.
As .korn outputs have binary format, it is not astonishing that they are not "human readable" with notepad. To view its content you should use DP_MICRESS.

Bernd

CharMIC
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Re: Primary Dendrite Arms spacing (PDAS) prediction

Postby CharMIC » Tue Oct 10, 2017 4:12 pm

Hej Bernd,

Is it a limitation of MICRESS, not being able to read large file.

If I cannot reduce the resolution or the domain size, how can I overcome this issue.

BR
Chamara

Bernd
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Joined: Mon Jun 23, 2008 9:29 pm

Re: Primary Dendrite Arms spacing (PDAS) prediction

Postby Bernd » Tue Oct 10, 2017 4:29 pm

Hej Chamara,

it is not a limitation of MICRESS - if the problem is really that the size of this file is too big, it is the memory of your computer and your operation system which is limiting. Of course, you can switch off writing the full-size composit output by chosing "no_out_Moving_Frame"...

Keep in mind that the .korn files contain integer values and need to be uncompressed before appending. Thus, even if the compressed file does not seem too big, it may get huge when being uncompressed...

How big is the file actually? Can you open it with DP_MICRESS? How many lines have been scrolled out due to moving frame action (you can check in column 9 of the .TabL file)?


Bernd

CharMIC
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Re: Primary Dendrite Arms spacing (PDAS) prediction

Postby CharMIC » Thu Oct 12, 2017 3:40 pm

Hej Bernd,

The file was about 25MB. Problem solved when I reduce the size.

I was not able to open it through DP_MICRESS. Perhaps it was the problem.

ralph
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Re: Primary Dendrite Arms spacing (PDAS) prediction

Postby ralph » Thu Oct 12, 2017 4:20 pm

Hej Chamara,

you can influence the amount of main memory which DP_MICRESS uses with Options->Edit settings

Settings.png
Settings.png (37.02 KiB) Viewed 65 times


However, even if can open it with DP_MICRESS that does not help MICRESS when it runs out of memory.

Ralph

CharMIC
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Re: Primary Dendrite Arms spacing (PDAS) prediction

Postby CharMIC » Thu Oct 26, 2017 1:15 pm

Hej Bernd,

Is it possible to simulate the mixed (columnar to equiaxis transition zone) solidification in MICRESS. I was thinking to add further nucleation of the same phase ahead of the solidification front?

BR
Chamara

Bernd
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Re: Primary Dendrite Arms spacing (PDAS) prediction

Postby Bernd » Fri Oct 27, 2017 12:02 am

Dear Chamara,

of course, you can do that.

However, getting this CET really quantitatively correct is difficult. The main reason is that you would have to do it in 3D, otherwise blocking the columnar front is too easy. Secondly, I think, neglecting latent heat may no longer be a good approximation under conditions of CET...

Bernd

CharMIC
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Re: Primary Dendrite Arms spacing (PDAS) prediction

Postby CharMIC » Wed Dec 06, 2017 5:04 pm

Bernd wrote:Hi Chamara,

you are right.

What you also could do is read the initial rectangular grain from a file which is shaped with small irregularities which serve as noise. If you now how it must look like, you could prepare such a file by hand using a text editor, starting from an "empty" ASCII output created by DP_MICRESS from a .korn or .phas output.

Alternatively, you can set a high number of smaller rectangular grains instead, or use my original idea to set only one grain in the corner which starts forming branches.

Bernd


Hej Bernd,

Would it be possible to explain this bit more. Now I am trying to create a rectangular grain with some noise as the initial microstructure.
I could not figure it out how to edit the .korn file using text editor.
If you can give me a simple example it would be great.

BR
Chamara

Bernd
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Joined: Mon Jun 23, 2008 9:29 pm

Re: Primary Dendrite Arms spacing (PDAS) prediction

Postby Bernd » Wed Dec 06, 2017 9:04 pm

Hej Chamara,

the point is that you need to use DP_MICRESS and export the .korn file to ASCII format. In the menu File you chose "export window content as dataset" and select the format "text (ascii)".
After that, you can edit the file with the text editor.

Bernd

CharMIC
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Re: Primary Dendrite Arms spacing (PDAS) prediction

Postby CharMIC » Tue Dec 12, 2017 3:37 pm

Hej Bernd,

Thanks for the clarification.

I manage to export .korn file to ascii file. And it looks like the figure attched here. Could you little bit explain the following

1. If I change the spacing and/or dimentions in the ascii file, do I have to change the resolution and/or dimentions in the dri file when I read the ascii file?

2. I can see 4 columns of data. what is the meaning of each column?

3. Is there a specific sequence in these data raws (how MICRESS reada and/or right the ascii file)
Attachments
ascii file.JPG
ascii file.JPG (37.39 KiB) Viewed 17 times


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