Why OpenFOAM Using OpenFOAM Simulation Cases Introduction about How to Use OpanFOAM Oliver Center for Scientific Computing December 8, 2012 Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Why OpenFOAM Using OpenFOAM Mesh Generating blockMesh snappyHexMesh Boundary and Solvers Simulation Cases Supersonic Flow over a Forward-facing Step Simple Pipeline Flow Make Your Own Solver Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases 1. OpenFOAM is an open source CFD software, which means you can make any modification, as long as you understant the code well. 2. Many researchers are doing their work based on OpenFOAM, and impliment many new methods into OpenFOAM based C++ code. Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Mesh Generating Boundary and Solvers Figure : Three popular commercial CFD software (from left to right: FLUENT, CFX, StarCCM+) Any CFD software must depends these 3 steps to solve a spcific flow problem: Pre-processing (mesh generating) −→ Set boundary condition, choose solver and run simulation (Solve PED) −→ Post-processing (flow field visulization) Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Mesh Generating Boundary and Solvers HOWEVER, the interface can be quite different. In OpenFOAM you can only see some folders structured like this: Figure : Folder structure in OpenFOAM (here Folder straight pipe is where we put simulation case file) Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Mesh Generating Boundary and Solvers blockMesh ./case/constant/polyMesh/blockMeshDict Vertices : (give pisition for each point) 0→1→2→3→0→4→5→6→7→4 (0, 0, 0)(1, 0, 0)(1, 1, 0)(0, 1, 0) (0, 0, 0.1)(1, 0, 0.1)(1, 1, 0.1)(0, 1, 0.1) Faces :(define the face plane) {0 3 2 1} {4 5 6 7} {0 3 7 4} {2 3 7 6} {1 2 6 5} {0 1 5 4} Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Mesh Generating Boundary and Solvers blockMesh blocks ( hex (0 1 2 3 4 5 6 7 ) (100 100 1 ) simpleGrading (2 0.5 1 ) ) Figure : Different simpleGrading value (left (1 1 1 ); right (3 3 1 )) Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Mesh Generating Boundary and Solvers blockMesh Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Mesh Generating Boundary and Solvers snappyHexMesh ./case/system/snapplyHexMeshDict The main problem is to generate .STL data file for each face. One possible way is to use StarCCM by exporting every splitted face. Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Mesh Generating Boundary and Solvers snappyHexMesh a b c Figure : snappyHexMesh meshing process (a: generating background mesh; b: cell splitting and cell removal; c: surface snapping) Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Mesh Generating Boundary and Solvers ./case/constant/polyMesh/boundary ./case/0/p ... Figure : boundary type Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Mesh Generating Boundary and Solvers Many Solvers can be chose according to your flow problem. The following two files can help choose the approperate numerical scheme. ./case/system/fvSolution ./case/system/fvScheme Table : Typical Solvers icoFoam pisoFoam sonicFoam dnsFoam ... Transient solver for incompressible, laminar flow of Newton Transient solver for incompressible flow Transient solver for trans-sonic/supersonic, laminar or turbu Direct numerical simulation solver for boxes of isotropic tur ... Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Supersonic Flow over a Forward-facing Step Simple Pipeline Flow Make Your Own Solver Figure : Geometry condition Mesh generating: blockMesh Boundary: inlet: fixedValue for U, p and T; outlet: zeroGradient; wall: non-slip (U fixedValue (0 0 0 ) ) Solver: sonicFoam Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Supersonic Flow over a Forward-facing Step Simple Pipeline Flow Make Your Own Solver Figure : contour distribution (top: pressure; leftbottom: velocity; rightbottom: tempreture) Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Supersonic Flow over a Forward-facing Step Simple Pipeline Flow Make Your Own Solver Mesh generating: snappyHexMesh Boundary: inlet: fixedValue for U=0.04, zeroGradient for p; outlet: zeroGradient for U and p; wall: non-slip Solver: icoFoam Figure : contour distribution (left: pressure; right: velocity) Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Supersonic Flow over a Forward-facing Step Simple Pipeline Flow Make Your Own Solver fluentToFoam Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Supersonic Flow over a Forward-facing Step Simple Pipeline Flow Make Your Own Solver Figure : Single bifurcation Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Supersonic Flow over a Forward-facing Step Simple Pipeline Flow Make Your Own Solver Figure : Double bifurcation Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Supersonic Flow over a Forward-facing Step Simple Pipeline Flow Make Your Own Solver Figure : Mesh for lungA017 Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Supersonic Flow over a Forward-facing Step Simple Pipeline Flow Make Your Own Solver Figure : Pressure and Velocity distribution for lungA017 at t=3.6 Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Supersonic Flow over a Forward-facing Step Simple Pipeline Flow Make Your Own Solver ∂ρU ∂t + ∇ · φU − ∇ · µ∇U = −∇p solve ( fvm::ddt(rho,U)+fvm::div(phi,U)-fvm::laplacian(mu,U)==fvc::grad(p) ) wmake → newApp Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Supersonic Flow over a Forward-facing Step Simple Pipeline Flow Make Your Own Solver passiveScalarFoam based on icoFoam Governing equation for a passive scaler s: ∂s ∂t + ∇ · (sU) = 0 1. Creat scaler s in creatField.H; volScalarField s ( IOobject ( ”s”, runTime.timeName(), mesh, IOobject::MUST READ, IOobject::AUTO WRITE ), mesh ); Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Supersonic Flow over a Forward-facing Step Simple Pipeline Flow Make Your Own Solver 2. Establish transport equation for s in passiveScalarFoam.C; solve(fvm::ddt(s)+fvm::div(phi,s)); 3. wmake passiveScalarFoam 4. creat s in 0 folder 5. define solution for s in system/fvSolution s { solver PBiCG; preconditioner DILU; tolerance 1e-06 relTol 0; } 6. define scheme for s in system/fvScheme div(phi,s) Gauss linearUpwind Gauss; Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Supersonic Flow over a Forward-facing Step Simple Pipeline Flow Make Your Own Solver run passiveScalarFoam Figure : Evolution of passive scalar s in rotate flow field Oliver Open∇FOAM Why OpenFOAM Using OpenFOAM Simulation Cases Supersonic Flow over a Forward-facing Step Simple Pipeline Flow Make Your Own Solver End Thank You Oliver Open∇FOAM

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