Difference between revisions of "TestHani"
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| − | == The ERCOFTAC diffuser case study, geometry and base case set-up == | + | == The ERCOFTAC diffuser case-study, geometry and base case set-up == |
| − | + | '''''', Chalmers University | |
| − | Maryse Page, Hydro Quebec, Montreal, Canada | + | '''Maryse Page''', Hydro Quebec, Montreal, Canada |
| − | The ERCOFTAC diffuser is an axi-symmetric expansion of a circular pipe. Figure 1 shows a 3D view of the geometry | + | The ERCOFTAC diffuser [1] is an axi-symmetric expansion of a circular pipe. Figure 1 shows a 3D view of the geometry. The inlet is in this case located at the end of the honeycomb that was used in the experiments to generate a plug flow with a solid body rotation/swirl. An artificial extension of the domain has been added at the end of the expansion. In the experiments it was open air after the end of the expansion. |
[[Image:ERCOFTAC_base_case_3dView.jpg]] | [[Image:ERCOFTAC_base_case_3dView.jpg]] | ||
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'''Figure 1. 3D view of the ERCOFTAC diffuser base case.''' | '''Figure 1. 3D view of the ERCOFTAC diffuser base case.''' | ||
| − | Figure 2 shows the definitions of the parameters rIn, diffuserLength, extensionLength and openingAngle. | + | The OpenFOAM ERCOFTAC base case described below was developed as a case-study for the third OpenFOAM workshop, Milano, 2008, and it can be found at the OpenFOAM-extend SourceForge project. It includes a parametrization of the geometry and the grid, and a complete OpenFOAM case that solves the flow in the domain. The parametrization is made using m4, and instructions on how to run m4 are included in the case. |
| + | Figure 2 shows the definitions of the parameters rIn, diffuserLength, extensionLength and openingAngle. It is thus easy to modify the geometry in terms of these parameters. | ||
[[Image:ERCOFTAC_base_case_2dView.jpg]] | [[Image:ERCOFTAC_base_case_2dView.jpg]] | ||
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'''Figure 2. 2D view of the ERCOFTAC diffuser base case.''' | '''Figure 2. 2D view of the ERCOFTAC diffuser base case.''' | ||
| − | Figure 3 shows | + | The grid generation in blockMesh is based on a number of cross-sections. It is easy to add or delete cross-sections in the m4 file if anyone would like to study another version of the same case. Figure 3 shows cross-sections A-G, that are used when making the mesh for the base case. The cross-sections refer to: |
| − | A: The outlet of the artificial extension. | + | A: The outlet of the artificial extension, and the outlet of the computational domain. |
B: The outlet of the diffuser. | B: The outlet of the diffuser. | ||
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F: The edge of a rotating part of the wall. | F: The edge of a rotating part of the wall. | ||
| − | G: The end of the honeycomb. | + | G: The end of the honeycomb, and the inlet of the computational domain. |
The number of cells in the z-direction between each cross-section is specified using parameters zABnumberOfCells (for the number of cells between cross-sections A and B), etc. | The number of cells in the z-direction between each cross-section is specified using parameters zABnumberOfCells (for the number of cells between cross-sections A and B), etc. | ||
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'''Figure 4. O-grid used in the parametrization.''' | '''Figure 4. O-grid used in the parametrization.''' | ||
| + | |||
| + | === Base case parametrization === | ||
| + | |||
| + | References: | ||
| + | [1] TODO: Reference to Clausen paper | ||
Revision as of 17:53, 13 January 2008
1 The ERCOFTAC diffuser case-study, geometry and base case set-up
Maryse Page, Hydro Quebec, Montreal, Canada
The ERCOFTAC diffuser [1] is an axi-symmetric expansion of a circular pipe. Figure 1 shows a 3D view of the geometry. The inlet is in this case located at the end of the honeycomb that was used in the experiments to generate a plug flow with a solid body rotation/swirl. An artificial extension of the domain has been added at the end of the expansion. In the experiments it was open air after the end of the expansion.
Figure 1. 3D view of the ERCOFTAC diffuser base case.
The OpenFOAM ERCOFTAC base case described below was developed as a case-study for the third OpenFOAM workshop, Milano, 2008, and it can be found at the OpenFOAM-extend SourceForge project. It includes a parametrization of the geometry and the grid, and a complete OpenFOAM case that solves the flow in the domain. The parametrization is made using m4, and instructions on how to run m4 are included in the case. Figure 2 shows the definitions of the parameters rIn, diffuserLength, extensionLength and openingAngle. It is thus easy to modify the geometry in terms of these parameters.
Figure 2. 2D view of the ERCOFTAC diffuser base case.
The grid generation in blockMesh is based on a number of cross-sections. It is easy to add or delete cross-sections in the m4 file if anyone would like to study another version of the same case. Figure 3 shows cross-sections A-G, that are used when making the mesh for the base case. The cross-sections refer to:
A: The outlet of the artificial extension, and the outlet of the computational domain.
B: The outlet of the diffuser.
C: The inlet of the diffuser.
D: A measurement plane.
E: The edge of a rotating part of the wall.
F: The edge of a rotating part of the wall.
G: The end of the honeycomb, and the inlet of the computational domain.
The number of cells in the z-direction between each cross-section is specified using parameters zABnumberOfCells (for the number of cells between cross-sections A and B), etc.
Figure 3. Planes used in the parametrization.
Figure 4 shows the parameters used for defining the O-grid throughout the domain. The figure is an example of the grid plane at cross-section A. The number of cells in the radial direction in the O-grid is specified using parameter rNumberOfCells, and the number of cells in the tangential direction is specified using parameter tNumberOfCells. The center block will get tNumberOfCells in both directions.
The radius of the cross-section is specified using parameter rA. The radius of the corners of the center block, relative to rA, is specified using the parameter rRelA, which should be between 0 and 1.
Figure 4. O-grid used in the parametrization.
1.1 Base case parametrization
References: [1] TODO: Reference to Clausen paper
