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2014-06-04 10:00
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rotor_detail.PNG (50,565 bytes) |
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It may be solved using a different approach about how to include body forces into the momentum equation, similar to what it is already made in interFoam solver. It seems like including body forces directly over momemtum equation is not correct and could affect dramatically in the case of rotorDiskSource http://www.cfd-online.com/Forums/openfoam-solving/90435-interpolation-pressure.html#post315788 IMPORTANT: I am running all simulations with simpleFoam |
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I second this. A small testcase can be found here https://drive.google.com/file/d/0BxalvZxv-zSEaHdGbWJtYS1pc3M/edit?usp=sharing |
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Thanks for the report. I have been considering calculating forces on faces, applying these directly in the pressure equation and using reconstruct in the momentum equation for some time. For some simple forces it is possible to construct them directly on the faces but for more complex forces e.g. involving grad, curl etc. it is only possible to construct in the cells and interpolate the values to the faces. However, the reconstruction will not guarantee that the integral over the cells is equal to the integral of the original cell values; i.e. no conservation of force, which might be an issue. Maybe some kind of integral correction could be applied to ensure conservation of force but I haven't looked into this in detail. Have you tested the idea of interpolating the force and using reconstruct? Is the force distribution improved and integrated force correct? |
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I am investigating this in conjunction with http://www.openfoam.org/mantisbt/view.php?id=1363 [^] as the issues relate. The basic principles are simple but in this case a significant rewrite of fvOptions will be required for an elegant implementation. However, the simple interpolation/reconstuction approach proposed will not necessarily conserve the volume integrated force, which for some force models may be important/critical. This is why I have not implemented the approach yet. I am now working on a special interpolation/reconstuction combination which will conserve the integrated force. |
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Thank you henry. I have not tested that idea. Is that idea the presented by Alberto here? http://www.cfd-online.com/Forums/openfoam-solving/90435-interpolation-pressure.html#post315788 I will be waiting for your conservative approach because I need it asap. It I can help you, please tell me. Best Regards Marcelino |
- Anonymous
