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Old   December 30, 2008, 10:57
Default Insufficent memory
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RY
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Hi,

I am wondering how much memory F3D needs? Is there any limitation on the total/active number of mesh?

My computer has Intel Xeon Quad-core 2.0GHz CPU and 3.25G RAM. However, after completing pre-processor, F3D stopped with an error message - "cannot allocate memory for vvect, possibly due to insufficient memory". My model has 4,524,435 (total) and 3,292,093 (active) cells.

I would appreciate any suggestions.

Thanks, RY
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Old   December 30, 2008, 20:25
Default Re: Insufficent memory
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CK
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RY I guess you are using windows 32-bit system right? the maximum allowable total cell count with 32-bit system is ~ 1,300,000. so, pls either reduced cell count or upgrade to 64-bit OS.
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Old   December 30, 2008, 22:44
Default Re: Insufficent memory
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michael barkhudarov
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RY,

The total memory used by FLOW-3D varies with the selected physical and numerical options. Generally, I would say the limit is rather around 4 million for a 32-bit system, that is, it will use 2 Gb of memory with around 4 million active cells.

One possibility to increase the maximum cell count (up to 7.0-7.5 mln) is to use the single precision version. Or, of course, switch to a 64-bit system, as CK suggests.
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Old   December 31, 2008, 08:50
Default Re: Insufficent memory
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RY
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Thanks CK and Michael.

Yes, I am using 32-bit WIN XP...will try to ask IT to upgrade the system.

However, it may not be possible to further reduce the cell number because cell size is limited by the small components in a much bigger geometry.

RY
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Old   January 1, 2009, 19:34
Default Re: Insufficent memory
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CK
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RY sound like you are solve problem which involved combination of very small object to very large objects. so do you mind to share what kind of problem that you are working at? do you faced any multi-block mesh error issue with your problem?

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Old   January 5, 2009, 14:26
Default Re: Insufficent memory
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RY
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Happy New Year CK.

I am studying the hydaulics in a flocculation basin, which includes two perforated baffles. Orifices on the baffles are much smaller than the basin geometry. As head loss through the orifices on baffles is very important, I have to limit the mesh size to resolve small orifices.

I try to avoid using multiblock meshing, as, to my experience, it would introduce errors if not being well designed, and would not be necessarily reduce computing time.

Any ideas?
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Old   January 9, 2009, 00:22
Default Re: Insufficent memory
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michael barkhudarov
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Ry,

Can the perforated baffles be represented with the porous baffle model with appropriate flow losses to avoid resolving the small openings?

Michael
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