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February 28, 2011, 09:35 |
Isat and OnlineLibrary
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#1 |
Member
Ali Shamooni
Join Date: Oct 2010
Posts: 44
Rep Power: 16 |
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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