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-   -   sliding interface problem (https://www.cfd-online.com/Forums/fluent/49181-sliding-interface-problem.html)

cesco September 4, 2008 05:07

sliding interface problem
 
following the fluent on line guide, I tried to simulate a profile rotating around a shaft, with moving mesh. The simulation is 2D. I created an internal circolar domain, with the pofile inside,that rotate around the origin, and an exernal circolar crown that is fixed. I merged the two meshes defining the interface. I have two problems. 1) nothing seems to pass through the interface 2) the lift coefficient results are about 1000000. How is it possible that nothing passes through the interface? Is this linked to the CL error?

mAx September 4, 2008 05:36

Re: sliding interface problem
 
have you defined the interfaces in fluent? what do yaou mean with "merged"? your edges, which define the interfaces, should be NOT connected each other

cesco September 4, 2008 06:59

Re: sliding interface problem
 
hi Max, thank you for you participation. with "merged" I mean that I created the two files *.msh and than I merged them with the t-merge utility of fluent, as explained in the guide. In this way there are two edges superimposed that are my interface. I set them as interfaces and than I created the grid interface in fluent. I'm working with a 360 circle so I set the interface as coupled instead of periodic. Once the iteration is completed I displaied the velocity contour and the stator zone appears not interested in the action of the flow. Why?

mAx September 4, 2008 07:29

Re: sliding interface problem
 
*is your computation converged? *do you see any discontinuity on both sides from the edges (typically pressure) *have you check your mesh (grid/check) If you still have doubt, I can take a look at your model (you can email me your model)

cesco September 4, 2008 09:08

Re: sliding interface problem
 
well i recived the suggestion to not select any option in the grid creation box, not periodic, not coupled. now I have already launched the iteration. If you would like to be so kind to analyse my case and data to find some errors (there are many for sure because I obtain cl and cd too big) I will appreciate. Tomorow I will send them to you. many thanks.

joao September 5, 2008 03:10

Re: sliding interface problem
 
Hi,

Did you initialize the flow manually? I had the same problem yesterday and after initialization, it was ok.

Regards

Joao

cesco September 5, 2008 03:22

Re: sliding interface problem
 
yes I initialized it manually. now the simulation I launched yesterday is still running so I still do not know if the prblem is solved but already now I can see from the plot Cl and Cd that the results are very far from periodic. Another problem I realized to have is that the simulation does not run if I let the fluid rotate without an asintotic velocity. I mean: if I set an inlet veocity 0, the iterations do not start...????????????? why??

joao September 5, 2008 08:42

Re: sliding interface problem
 
Hi,

When you first loaded the case file, was there any error message?


cesco September 5, 2008 10:37

Re: sliding interface problem
 
no, no error messeges. all seems to be good but the inner domain does nt rotate inside the other without seeting an asintoti velocity.

cesco September 5, 2008 10:38

Re: sliding interface problem
 
no, no error messeges. all seems to be good but the inner domain does nt rotate inside the other without seeting an asintoti velocity.



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