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-   -   Problems With courant number Icofoam (http://www.cfd-online.com/Forums/openfoam-solving/88604-problems-courant-number-icofoam.html)

basilwatson May 21, 2011 09:39

Problems With courant number Icofoam
 
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Hi all
running a simple pipe with 4 outlets. 16mm dia and 800 long ( 3 m/sec volocity ( too fast?? for Icofoam ?) through 2 right angle bends and exercise in learning. Exported as STEP ,set up and meshed in Salome , exported using ideasToFoam

so far so good ,

Calculated the courant Number as per instructions. ( problem 1 when exporting a mesh where is the cell size < I used checkmesh but.... Used Netgen I THINK the cell size is 0.3)

I can get it to run but only with the following control dict

application icoFoam;

startFrom startTime;

startTime 0;

stopAt endTime;

endTime 0.008;

deltaT 0.004;//0.005;

writeControl timeStep;

writeInterval 1;

purgeWrite 0;

writeFormat ascii;

writePrecision 9;

writeCompression uncompressed;

timeFormat general;

timePrecision 9;


any other changes or outside of the ratio..0.008 to 0.004 and I get a large courant number and a floating point exception

even with a ridiculously small time step and end time

What am I doing wrong ? Have I defined the problem correctly do you think?

Kind regards Stephen


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