| | | Materialien für den 3D-Druck im Hochtemperaturbereich, eine Pressemitteilung
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Autor
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Thema: Coaxial rotating cylinders (1326 mal gelesen)
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Xiana Mitglied phD student
Beiträge: 1 Registriert: 29.05.2007
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erstellt am: 29. Mai. 2007 17:21 <-- editieren / zitieren --> Unities abgeben:
Hi, I am simulating the flow between 2 rotating coaxial cylinders with radius of 0,25 and 0,20 m. I´ve defined my inlet, a ring at the bottom of the anular space, like a velocity inlet with 1m/s in axial direction, the outlet, a ring at the top, like a pressure outlet and the fluid like a reference frame which rotates at 1000rpm. I´ve used the Reynolds Stress Model to model the turbulence but I still have a lot of problems to get a converged solution. The residuals remain high and with oscillations, specially the continuity, because ich have a lot of reversed flow and the balance of mass flow doesn´t agree. Can anyone help me to loose this problem?! Thank you very much Xiana Eine Antwort auf diesen Beitrag verfassen (mit Zitat/Zitat des Beitrags) IP |
Ulrich Heck Moderator OpenFOAM Tool Entwicklung
Beiträge: 291 Registriert: 08.09.2003 CastNet (DHCAE Tools) OpenFOAM CalculiX
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erstellt am: 30. Mai. 2007 08:38 <-- editieren / zitieren --> Unities abgeben: Nur für Xiana
Hi Xiana, is there a special reason to use the Reynolds-Stress model? The turbulence seems to be almost caused by the shear conditions and if your flow is almost axial than other turbulence models (such as realizable k-eps) should work as well and run more stable. Of course if you have large swirls (as in cyclones) you have to use Reynolds-Stress. Maybe there is no need to use the reference frame model. You can also define a rotating wall by applying the angular velocity on the wall. I sometimes make the experience that the solver has problems to converge, when the pressure outlet isn't on a physical isobaric surface, meaning that there is a pressure gradient in the outlet. Maybe you can arrange the outlet surface, that it is almost isobaric. Maybe you should consider as well another initialization of the solution. I hope this helps Ulrich
------------------ Dr.-Ing. Ulrich Heck ulrich_heck@dhcae.de http://www.dhcae.de Eine Antwort auf diesen Beitrag verfassen (mit Zitat/Zitat des Beitrags) IP |
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