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Old   February 28, 2011, 09:30
Default Isat and Online library
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Ali Shamooni
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Hi Everyone

I use OpenFoam-1.5-dev
ChemistryOnlineLibrary class already defined in it i think by Dr Tomaaso Lucchini Does anyone have any idea about how to use it?

i saw the post below by Lucchini about how to use it but its complicating for me:

"
onlineLibrary is used to tabulate the complex chemistry to reduce the computational time. It is a constant approximation version of the ISAT (in-situ adaptive tabulation) algorithm developed by Pope.

If you want to use the tabulated chemistry, the onlineProperties dictionary should be written as follows:

onlineProperties
{
tauStar off;

online on;

tolerance 1.0e-5;

logT off;

maxElements 100000;

cleanAll off;

scaleFactor
{
otherSpecies 1.0;
Temperature 1700;
Pressure 1.0e+10;
}

scaleFactorSolution
{
otherSpecies 1.0;
Temperature 1700;
Pressure 1.0e+10;
}

}

if you want to switch it off,

onlineProperties
{
tauStar off;

online off;

tolerance 1.0e-5;

logT off;

maxElements 100000;

cleanAll off;

scaleFactor
{
otherSpecies 1.0;
Temperature 1700;
Pressure 1.0e+10;
}

scaleFactorSolution
{
otherSpecies 1.0;
Temperature 1700;
Pressure 1.0e+10;
}

}

In the ISAT algorithm chemical source terms are tabulated into a binary tree and are used to approximate the chemical source terms of the nearest composition according to a specified tolerance.

Explanation of the terms:

tauStar: switch it off, it will be used in the future;
logT: if this option is switched on, the logarithm of the temperature will be tabulated instead of the temperature
maxElements: maximum number of elements to be tabulated (up to 5e6 is fine, then you can seriously run into memory troubles)
cleanAll: if switched on, it will clean the library after any time step. If you want to exploit the full capabilities of the method, switch it off
scaleFactor: tabulated data consist of chemical compositions, temperature and pressure. You can scale chemical compositions, temperature and pressure to get more points found
solutionScaleFactor: the same but used to extend the validity range of a tabulated composition.

For further details, please refer to the Pope's paper (you can find them on the web also) and to the code implementation. In particular
- chemistrySolve.C
- chemistryOnlineLibrary.C
should be fine to start looking at them.

If you need more help or you like to setup a possible collaboration, please contact me.

That's all for the moment, have fun with OpenFOAM and combustion.

Tommaso
"
where is chemistrySolve.C ?
i added online properties in chemistryproperties input file
but it didnt work

Thanks
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