OpenFOAM Introduction - ULiege

1 OpenFOAMI ntroductionSpeakers:Francois 2016 OpenFOAM What's OpenFOAM ? OpenFOAM : Open source Field Operation AndManipulation C++ toolbox for the development of customizednumerical solvers, and pre-/post-processing utilitiesfor the solution of continuum mechanics problems,including computational fluid dynamics (CFD). OpenFOAM What comes with OpenFOAM ? Basic CFD solvers Incompressible flow with RANS and LES Advanced CFD solvers Compressible flow solvers with RANS and LES Buoyancy-driven flow solvers Multiphase flow solvers Combustion problems Solvers for conjugate heat transfer Particle Tracking Molecular dynamics solvers[28] Electromagnetics solvers Solid dynamics solvers OpenFOAM What are the applications of OpenFOAM ? CATIA Room Ubuntu Login User: foam Pass: catia1135 Linux Basics Open Terminal: In gnome : Applications Accesories Terminal In KDE : Applications menu Systems Konsole Linux Basics Create Folder ~$mkdir name Copy files ~$cp name destination Delete files(attention: no undelete option) ~$rm name Rename file ~$mv name_original name_new To edit a file, we'll use Gedit $gedit filename Linux Basics Change directory ~$cd folder Go to home directory ~$cd See working directory ~$pwd See working directory's content ~$ls OpenFOAM Basics Create a directory named student_work_2016_A in the OpenFOAM workdirectory ~$cd ~$cd Note.

2 You can use the <tab> key to autocomplete the line ~$mkdir student_work_2016_A Copy the cavity problem to the created directory ~$cp -r tutorials/incompressible/icoFoam/cavity student_work_2016_A/ Go to student_work_2016_A ~$cd student_work_2016_A Rename the folder to Cavity_original ~$mv cavity cavity_original Go to cavity_original folder ~$cd cavity_original OpenFOAM Basics Folder structure OpenFOAM Basics Test case problem: lid-driven cavity OpenFOAM Basics Block Structure of of mesh OpenFOAM Basics blockMeshDictconvertToMeters ;vertices ( (0 0 0) (1 0 0) (1 1 0) (0 1 0) (0 0 ) (1 0 ) (1 1 ) (0 1 )); OpenFOAM Basics blockMeshDictblocks ( hex (0 1 2 3 4 5 6 7) (20 20 1) simpleGrading (1 1 1)); OpenFOAM Basics blockMeshDictboundary( movingWall { type wall; faces ( (3 7 6 2) ); } fixedWalls { type wall; faces ( (0 4 7 3) (2 6 5 1) (1 5 4 0) ); }.)

3 FrontAndBack { type empty; faces ( (0 3 2 1) (4 5 6 7) ); }); OpenFOAM Basics To generate the mesh from the blockMeshDict: ~$blockMesh To visualize the mesh: ~$paraFoam OpenFOAM Basics In paraFoam:a)Apply in the Object Inspectorb)Surface With edges in the representation menuab OpenFOAM Basics Problem set-up Initial values: Folder 0 U p Properties: Folder constant TransportProperties Numerical Control: Folder system controlDict fvSchemes fvSolution OpenFOAM Basics File: p dimensions [0 2 -2 0 0 0 0];internalField uniform 0;boundaryField{ movingWall { type zeroGradient; } fixedWalls { type zeroGradient; } frontAndBack { type empty; }} OpenFOAM Basics File: U dimensions [0 1 -1 0 0 0 0];internalField uniform (0 0 0);boundaryField{ movingWall { type fixedValue; value uniform (1 0 0); } fixedWalls { type fixedValue; value uniform (0 0 0); } frontAndBack { type empty; }} OpenFOAM Basics File: U For external flowsdimensions [0 1 -1 0 0 0 0];internalField uniform (0 0 0);boundaryField{ dummyWall { type freestream; freestreamValue uniform (1 0 0); }} OpenFOAM Basics File: transportProperties nu [ 0 2 -1 0 0 0 0 ] ; OpenFOAM Basics File: controlDict application icoFoam;startFrom startTime;startTime 0;stopAt endTime;endTime ;DeltaT.

4 // CFL is imposed through twriteControl timeStep;writeInterval 20;purgeWrite 0;writeFormat ascii;writePrecision 6;writeCompression off;timeFormat general;timePrecision 6;runTimeModifiable true;CFL= t|U| x OpenFOAM Basics To run the case ~$icoFoam To visualize the results: ~$paraFoam paraFoam Basicsa paraFoam Basicsbcd paraFoam Basics Common toolbarGlyph: to show arrowsStream tracer: to showstreamlines Student WorkMesh Grading Problem is based on the lid-driven cavity tutorial It introduces the mesh grading feature Student Work Test case problem: lid-driven cavity Student Work Student Work Create a directory named student_work_2016_A in theOpenFOAM work directory ~$cd ~$cd Note: you can use the <tab> key to autocomplete the line Copy the cavity problem to the created directory ~$cp -rtutorials/incompressible/icoFoam/cavit ystudent_work_2016_A/ Go to student_work_2016_A ~$cd student_work_2016_A/ Rename the folder to cavity_grading ~$mv cavity cavity_grading Student Work blockMeshDictvertices( ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( )); Student Work blockMeshDictblocks( hex (0 1 4 3 9 10 13 12) (10 10 1) simpleGrading (2 2 1) hex (1 2 5 4 10 11 14 13) (10 10 1) simpleGrading ( 2 1) hex (3 4 7 6 12 13 16 15) (10 10 1) simpleGrading (2 1) hex (4 5 8 7 13 14 17 16) (10 10 1) simpleGrading ( 1)).

5 Student Workboundary( movingWall { type wall; faces ( (6 15 16 7) (7 16 17 8) ); } fixedWalls { type wall; faces ( (3 12 15 6) (0 9 12 3) (0 1 10 9) (1 2 11 10) (2 5 14 11) (5 8 17 14) ); }.. frontAndBack { type empty; faces ( (0 3 4 1) (1 4 5 2) (3 6 7 4) (4 7 8 5) (9 10 13 12) (10 11 14 13) (12 13 16 15) (13 14 17 16) ); }); Student Work Build mesh ~$blockMesh Run the files: ~$icoFoam View the results: ~$paraFoam OpenFOAM Integrals To calculate the integral of variable over apatch General structure ~$ patchIntegrate <variable> <patch> For example: ~$ patchIntegrate U movingWall OpenFOAM Integrals To calculate forces general;timePrecision 6;runTimeModifiable true.

6 Functions{ #include "forceCoeffs"} OpenFOAM Integrals To calculate forces forceCoeffs Adapted fromtutorials/incompressible/simpleFoam/ motorBike/system/forceCoeffs/*---------- ----------------------*- C++ -*----------------------------------*\| ========= | || \\ / F ield | OpenFOAM : The Open Source CFD Toolbox || \\ / O peration | Version: + || \\ / A nd | Web: || \\/ M anipulation | |\*------------------------------------- --------------------------------------*/ forceCoeffs1{ type forceCoeffs; functionObjectLibs ( " " ); outputControl timeStep; timeInterval 1; log yes; patches ( patchesName ); rhoName rhoInf; // Indicates incompressible rhoInf 1; // Redundant for incompressible liftDir (0 0 1); dragDir (1 0 0); CofR (1 0 0); // Axle midpoint on ground pitchAxis (0 1 0); magUInf 20; lRef ; // Reference length Aref ; // Reference Area}Remember to set the correct values!

7 !!CL=2FL U 2 ACD=2FD U 2A References Linux Just google: linux commands OpenFOAM OpenFOAM User Guide Installing OpenFOAM +/