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Previous: Parallel run Up: Running in parallel Next: Boundary conditions in OpenFOAM

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Parallel reconstruction of solution

  • To reconstruct solution use application reconstructPar:

    # reconstructPar -latestTime

    /*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  dev                                   |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build  : dev-e2ccbbbb
Exec   : reconstructPar -latestTime
Date   : Jun 16 2017
Time   : 12:03:00
Host   : $HOSTNAME
PID    : $$
Case   : $FOAM_RUN/pitzDaily
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster (fileModificationSkew 10)
allowSystemOperations : Allowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time



Reconstructing fields for mesh region0

Time = 295

Reconstructing FV fields

    Reconstructing volScalarFields

        p
        nut
        k
        epsilon

    Reconstructing volVectorFields

        U

    Reconstructing surfaceScalarFields

        phi

Reconstructing point fields

No point fields

No lagrangian fields


End
  • In case directory appears a new directory with last time layer of the solution
  • Local data from processors are not deleted after reconstruction

OpenFOAM Training by CFD Support,   CFD SUPPORT,   info@cfdsupport.com    +420 212 243 883      © CFD support, s.r.o., Sokolovská 270/201, 190 00 Praha 9, Czech Republic

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Next: Model setting without an Up: Alternative formulation Previous: Alternative formulation   Contents   Index

Temporal and Spatial Discretization Settings - fvSchemes File

The sub-dictionary ddtSchemes defines a temporal discretization. The cases are solved as steady state problems:

 

ddtSchemes
{
    default         steadyState;
}

In file fvSchemes the important sub-dictionary is divSchemes. The following second order setup of divergence schemes is recommended:

 

divSchemes
{
    default          none;
    
    div(phi,U)       bounded Gauss limitedLinear 1.0;
    div(phi,k)       bounded Gauss upwind;
    div(phi,omega)   bounded Gauss upwind;
    div(phi,epsilon) bounded Gauss upwind;
    
    div((nuEff*dev(T(grad(U))))) Gauss linear;
}

For complicated unstable case, an alternative may be first order setup of divergence schemes:

 

divSchemes
{
    default          none;
    
    div(phi,U)       bounded Gauss upwind;
    div(phi,k)       bounded Gauss upwind;
    div(phi,omega)   bounded Gauss upwind;
    div(phi,epsilon) bounded Gauss upwind;
    
    div((nuEff*dev(T(grad(U))))) Gauss linear;
}

OpenFOAM Training by CFD Support,   CFD SUPPORT,   info@cfdsupport.com    +420 212 243 883      © CFD support, s.r.o., Sokolovská 270/201, 190 00 Praha 9, Czech Republic

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Previous: Cell Centered Approach Up: TCFD Solvers Next: System of Linear Equations
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Under-Relaxation

Under-Relaxation reduces solution oscillations and helps to keep the computation stable. After each iteration, at each cell, a new value for variable img188 in cell $ i$ is then updated using following equation: img189 where $ \alpha$ is under-relaxation factor. The choice $ \alpha$ $ =$ $ 1$ corresponds to no under-relaxation. The choice $ \alpha$ $ <$ $ 1$ is under-relaxation. This may slow down speed of convergence but increases the stability of the computation, i.e. it decreases the possibility of divergence or oscillations in the solution. For more details see e.g. [1].

OpenFOAM Training by CFD Support,   CFD SUPPORT,   info@cfdsupport.com    +420 212 243 883      © CFD support, s.r.o., Sokolovská 270/201, 190 00 Praha 9, Czech Republic