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Computation setup
- Parameters of computational process are set in files in directory system
- Let us look inside:
# ls $FOAM_RUN /cavity/systemblockMeshDict controlDict fvSchemes fvSolution
- File controlDict controls the computation in terms of starting time, time step, end time, writing data etc.
- Let us watch the filed:
# cat $FOAM_RUN /cavity/system/controlDict/*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: dev | | \\ / A nd | Web: www.OpenFOAM.org | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class dictionary; location "system"; object controlDict; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // application icoFoam; startFrom startTime; startTime 0; stopAt endTime; endTime 0.5; deltaT 0.005; writeControl timeStep; writeInterval 20; purgeWrite 0; writeFormat ascii; writePrecision 6; writeCompression off; timeFormat general; timePrecision 6; runTimeModifiable true; // ************************************************************************* // - Parameter application describes the name of the solver that is going to be used
- Parameter startFrom defines from which data the computation starts (initial conditions). It is usually set to startTime – starts from certain time layer e.g. from /0 Useful alternative is latestTime, which automatically chooses the latest time layer
- If parameter startFrom is set to startTime the parameter startTime stands for time layer to start from
- Parameter stopAt specifies how the computation is stopped. The most common is endTime. Alternatives are writeNow, noWriteNow or
nextWrite. - Parameter endTime is time when the computation stops
- Parameter deltaT is the time step
- Parameter writeControl says how often is the solution saved. Commonly used is timeStep saving solution after certain number of iterations. It is useful to save solution at certain clock time clockTime. Additionally, it can be saved in regular physical time runTime, or in regular computational time cpuTime.
- Parameter writeInterval is a corresponding value for writeControl
- Parameter purgeWrite can handle keeping only last
time layers to avoid overfilling hard-disks. If purgeWrite is set to zero, nothing happens. - Parameter writeFormat stands for data format (ascii/binary)
- Parameter writePrecision says how many decimal points are stored (ascii only)
- Parameter writeCompression says if data compression is on/off (compressed/uncompressed)
- Parameter timeFormat stands for format of time layers (name of directories)
- Parameter timePrecision stands for decimal points in time layer directories
- Parameter runTimeModifiable allows changes during computation (yes/no)
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