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Tutorial calculation in “An Introduction to Computational Fluid Dynamics”
- 1. Tutorial calculation in“An Introduction to Computational Fluid Dynamics” yotakagi77 August 5th, 2017
- 2. Ex. 11.1 Heatconduction problem in unstructured grid.
- 3. Grid generation • Firsttrial – blockMesh w/ wedge – blockMesh wo/ wedge – Square to triangle – Shift, mirror, shift, merge, mirror, rotate, …. – Modification of boundary patches is boring.
- 4. Grid generation • Secondtrial – Hand writing polyMesh data – Investigation of a simple grid, e.g. two triangles.
- 5. polyMesh • points • faces •owner • neighbor • boundary 0 1
- 6. Let’s try manualmeshing! • Three triangles
- 7. Mesh generation withsection paper
- 8. Mesh generation withsection paper
- 9. polyMesh of halfmodel • 22 points • 37 faces • 8 internal faces • 6 patches – adiabatic, low T., middle T., high T., symmetry, empty
- 10. Heat conduction calculation •Solver: laplacianFoam • Physical property – Thermal diffusivity, DT (=a) • r = 7.83 x 103 kg/m3 • Cp = 461 J/kg·K • k = 50 W/m·K • a = k / (rCp) = 0.0147 m2/s
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- 13. refineMeshDict // Cells torefine; name of cell set set c0; // Type of coordinate system: // - global : coordinate system same for every cell. Usually aligned with // x,y,z axis. Specify in globalCoeffs section below. // - patchLocal : coordinate system different for every cell. Specify in // patchLocalCoeffs section below. // - fieldBased : uses the list of field names from the directions list for // selecting the directions to cut. Meant to be used with geometricCut, but // can also be used with useHexTopology. //coordinateSystem global; coordinateSystem patchLocal; //coordinateSystem fieldBased; // .. and its coefficients. x,y in this case. (normal direction is calculated as tan1^tan2) globalCoeffs { tan1 (1 0 0); tan2 (0 1 0); }
- 14. refineMeshDict patchLocalCoeffs { patch frontAndBack; //Normal direction is facenormal of zero'th face of patch tan1 (1 0 0); tan2 (0 1 0); } // List of directions to refine, if global or patchLocal directions ( tan1 tan2 normal ); // List of directions to refine, if "fieldBased". Keep in mind that these // fields must be of type "vectorField", not "volVectorField". //directions //( // radialDirectionFieldName // angularDirectionFieldName // heightDirectionFieldName //);
- 15. refineMeshDict // Whether touse hex topology. This will // - if patchLocal: all cells on selected patch should be hex // - split all hexes in 2x2x2 through the middle of edges. //useHexTopology true; useHexTopology false; // Cut purely geometric (will cut hexes through vertices) or take topology // into account. Incompatible with useHexTopology //geometricCut false; geometricCut true; // Write meshes from intermediate steps writeMesh false;