OpenFOAM programming tutorial

Tommaso Lucchini

Description

POLITECNICO DI MILANO CHALMERSOpenFOAM programming tutorialTommaso LucchiniDepartment of EnergyPolitecnico di MilanoTommaso Lucchini/ OpenFOAM programming tutorialPOLITECNICO DI MILANO CHALMERSOutline• Overview of the OpenFOAM structure• A look at icoFoam• Customizing an application• Implementing a transport equation in a new application• Customizing a boundary condition• General informationTommaso Lucchini/ OpenFOAM programming tutorialPOLITECNICO DI MILANO CHALMERSStructure of OpenFOAMThe OpenFOAM code is structures as follows (typefoam and thenls).• applications: source files of all the executables:◮ solvers◮ utilities◮ bin◮ test• bin: basic executable scripts.• doc: pdf and Doxygen documentation.◮ Doxygen◮ Guides-a4• lib: compiled libraries.• src: source library files.• test: library test source files.• tutorials: tutorial cases.• wmake: compiler settings.Tommaso Lucchini/ OpenFOAM programming tutorialPOLITECNICO DI MILANO CHALMERSStructure of OpenFOAMNavigating the source code• Some useful commands to navigate inside the OpenFOAM sources:◮ app =$WM_PROJECT_DIR/applications◮ sol =$WM_PROJECT_DIR/applications/solvers◮ util =$WM_PROJECT_DIR/applications/utilities◮ src =$WM_PROJECT_DIR/src• Environment variables:◮ $FOAM_APP = $WM_PROJECT_DIR/applications◮ $FOAM_SOLVERS = $WM_PROJECT_DIR/applications/solvers◮ $FOAM_UTILITIES = $WM_PROJECT_DIR/applications/utilities◮ $FOAM_SRC = $WM_PROJECT_DIR/src• OpenFOAM source code serves ...

Informations

• Publié par: Nopod
• Nombre de lectures: 951
• Langue: English

Extrait

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Tommaso Lucchini

Department of Energy Politecnico di Milano

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OpenFOAM programming tutorial

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Outline

 Customizing an application

 Implementing a transport equation in a new application

 General information

 Customizing a boundary condition

 Overview of the OpenFOAM structure

 A look at icoFoam

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Structure of OpenFOAM The OpenFOAM code is structures as follows (typefoamand thenls).  applications: source les of all the executables: ◮ solvers ◮ utilities ◮ bin ◮ test

 bin: basic executable scripts.

 doc: pdf and Doxygen documentation. ◮ Doxygen ◮ Guides-a4

 src: source library les.

 lib: compiled libraries.

 tutorials: tutorial cases.

 test: library test source les.

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 wmake: compiler settings.

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 OpenFOAM source code serves two functions: ◮  Ready to run inEfcient and customised top-level solver for class of physics. a manner of commercial CFD/CCM software ◮ Example of OpenFOAM classes and library functionality in use

Structure of OpenFOAM Navigating the source code

 commands to navigate inside the OpenFOAM sources:Some useful ◮ app=$WM_PROJECT_DIR/applications ◮ sol=$WM PROJECT DIR/applications/solvers _ _ ◮ util=$WM PROJECT DIR/applications/utilities _ _ ◮ src=$WM PROJECT DIR/src _ _

 Environment variables: ◮  $WM PROJECT DIR/applications =$FOAM APP _ _ _ ◮ $FOAM SOLVERS $WM PROJECT DIR/applications/solvers = _ _ _ ◮ $FOAM UTILITIES = $WM PROJECT DIR/applications/utilities _ _ _ ◮ $FOAM SRC $WM PROJECT DIR/src = _ _ _

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Walk through a simple solver

Solver walk-through:icoFoam  Types of les ◮ Header les Located before the entry line of the executable int main(int argc, char* argv[]) Contain various class denitions Grouped together for easier use ◮ Include les Often repeated code snippets, e.g. mesh creation, Courant number calculation and similar Held centrally for easier maintenance Enforce consistent naming between executables, e.g.mesh,runTime ◮ Local implementation les Main code, named consistently with the executable createFields.H

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Walk through icoFoam File organization sol→cd incompressible→cd icoFoam  TheicoFoamdirectory consists of what follows (typels): createFields.H FoamX/ icoFoam.C icoFoam.dep Make/  TheFoamXdirectory is for pre-processing.  TheMakedirectory contains instructions for thewmakecompilation command.  icoFoam.Cis the main le, whilecreateFields.His included byicoFoam.C.  The lefvCFD.H,included byicoFoam.C, contains all the class denitions which are needed byicoFoam. See the leMake/optionsto understand wherefvCFD.His included from: ◮ $FOAM_SRC/finiteVolume/lnInclude/fvCFD.H, symbolic link to: $FOAM SRC/finiteVolume/cfdTools/general/include/fvCFD.H _  Use the commandfind PATH -iname "*LETTERSINFILENAME*"to nd where inPATHa le name containingLETTERSFILENAMEin its le name is located. _ _ Example:find $WM PROJECT DIR -iname "*fvCFD.H*"

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Walk through icoFoam A look into fvCFD.H

#include "Time.H" #include "fvMesh.H" #include "fvc.H" #include "fvMatrices.H" #include "fvm.H" #include "linear.H" #include "calculatedFvPatchFields.H" #include "fixedValueFvPatchFields.H" #include "adjustPhi.H" #include "findRefCell.H" #include "mathematicalConstants.H"

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The inclusion les beforemain are all the class denitions required byicoFoam. Have a look into the source les to understand what these classes do.

#include "OSspecific.H" #include "argList.H"

#ifndef namespaceFoam #define namespaceFoam using namespace Foam; #endif

#endif

#ifndef fvCFD H _ #define fvCFD H _

#include "parRun.H"

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Walk through icoFoam A look into icoFoam.C, case setup and variable initialization  icoFoamstarts with int main(int argc, char *argv[]) whereint argcandchar *argv[]are the number of parameters and the actual parameters used when runningicoFoam.

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# include "createTime.H" # include "createMesh.H" # include "createFields.H" # include "initContinuityErrs.H" where all the included les exceptcreateFields.Hare in $FOAM SRC/finiteVolume/lnInclude. _

 The case is initialized by: # include "setRootCase.H"

 createFields.His located in theicoFoamdirectory. It initializes all the variables used inicoFoama look inside it and see how variables are. Have created.

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Walk through icoFoam A look into icoFoam.C, time-loop code

 The momentum equations are dened and a velocity predictor is solved by: fvVectorMatrix UEqn ( fvm::ddt(U) + fvm::div(phi, U) - fvm::laplacian(nu, U) );

 ThefvSolutionsubdictionaryPISOis read, and the Courant Number is calculated and written to the screen by (use thefindcommand): # include "readPISOControls.H" # include "CourantNo.H"

 The time-loop starts by: for (runTime++; !runTime.end(); runTime++) and the rest is done at each time-step

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 A PISO corrector loop is initialized by: for (int corr=0; corr<nCorr; corr++)  The PISO algorithm uses these member functions: ◮ A()returns the central coefcients of anfvVectorMatrix ◮ H()returns the H operation source of anfvVectorMatrix ◮ Sf()returns cell face area vector of anfvMesh ◮ flux()returns the face ux eld from anfvScalarMatrix ◮ correctBoundaryConditions()corrects the boundary elds of a volVectorField  Identify the object types (classes) and use the OpenFOAM Doxygen (oa/f:/tpceursom.thlmyxeg/ntht/doc/Doforge.ne) to better understand them what they do

Walk through icoFoam A look into icoFoam.C, the PISO loop

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 At the end oficoFoamthere are some write statements runTime.write();

Info<< "ExecutionTime = " << runTime.elapsedCpuTime() << " s" << " ClockTime = " << runTime.elapsedClockTime() << " s" << nl << endl;

 write()that all the variables that were dened as anmakes sure IOobject withIOobject::AUTO WRITEare written to the time directory according to the _ settings in the$FOAM_CASE/system/controlDictle.  elapsedCPUTime()is the elapsed CPU time.  elapsedClockTime()is the elapsed wall clock time.

Walk through icoFoam A look into icoFoam.C, write statements

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