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-   -   rotating disk in a cylinder (https://www.cfd-online.com/Forums/fluent/131528-rotating-disk-cylinder.html)

bhanu March 16, 2014 19:36

rotating disk in a cylinder
 
hi all,
i am working on a rotating disk in a cylinder and the problem is i am not getting what i should use to rotate my disk. i have got half cylinder filled with water and half is air.everything is stationary except my disk that is moving rotational. i am working to see the film formation on a disk and want to see the disk rotate as it's make film on it...
if any body can help me with that, i would be so delighted and thankful.

-mAx- March 25, 2014 02:02

with which software did you mesh your geometry?
pictures may help

bhanu March 25, 2014 09:40

2 Attachment(s)
hi max,
i have used gambit for modeling and meshing and my meshing is also an another issue that i am not able to do a good meshing so if you can help me with meshing would be great. here i am attaching the picture of model with meshing and without meshing.Attachment 29614

Attachment 29615

bhanu March 25, 2014 09:42

1 Attachment(s)
the model without meshingAttachment 29616

-mAx- March 26, 2014 01:21

if you want rotate your mesh, then rotor and stator have to be disconnected.
In Gambit pick and move rotor volume anywhere. If you can then rotor and stator are disconnected.
If you cannot (error message), it means they are connected

Once it is done you have to define interfaces for being able to use sliding mesh

bhanu March 26, 2014 04:51

Yeah my rotor and stator are disconnected and i have used interface system. Let me clear it first i made my disk first than i subtracted from a bit bigger disk. That is aside and than i made cylinder and one same size of bigger disk and than an outer cylinder. Split both cylinders and than substract disk from inner cylinder so that's how i got interfaces.

-mAx- March 26, 2014 05:26

can you provide your *.dbs file?

bhanu March 27, 2014 20:23

yeah for sure but i don't know how to send that file here???:(

bhanu March 27, 2014 20:29

can you give me your mail id so i can send you tht file through my mail??

-mAx- March 28, 2014 00:21

upload it on a share server, like dropbox or whatever

bhanu March 28, 2014 07:42

https://www.dropbox.com/s/nkmx0pfxttfy1t3/bhanu.dbs
if you can suggest me something for meshing that would be great

-mAx- March 31, 2014 00:40

you only defined one fluid domain "wa&li"
Actually you need 2 if you want rotate your impeller: stator and stator.
If I see you interface, you should set volume.2 & volume.7 as rotor.

bhanu March 31, 2014 07:55

Yeah i tried that one as well but that means i am rotating the fluid and that is not i want cause in my case only the disk is rotating and fluid is stable. And i am trying to get good meshing on it do you have any suggestion for tht ???

-mAx- March 31, 2014 08:13

Quote:

Originally Posted by bhanu (Post 483000)
Yeah i tried that one as well but that means i am rotating the fluid

Wrong !
Since you didn't set anything in fluent, you cannot say that rotor is "moving" and stator is fixed.
At this point you are only ready to treat 2 separated zones.

bhanu March 31, 2014 21:08

but i have given the boundary condition in fluent for my disk that moves my disk. in that i have given rotational speed for my disk. but if i make another cell zone condition for my disk and if i than give the mesh motion that means i am rotating my fluid at the disk position. !!!

bhanu March 31, 2014 21:17

if you please have a look on this file you might will understand what i am trying to say https://www.dropbox.com/s/061a97nopo9fzyp/bhanu.cas

-mAx- April 1, 2014 00:49

Quote:

Originally Posted by bhanu (Post 483107)
if you please have a look on this file you might will understand what i am trying to say https://www.dropbox.com/s/061a97nopo9fzyp/bhanu.cas

I don't have fluent (anymore)
Quote:

Originally Posted by bhanu (Post 483105)
but i have given the boundary condition in fluent for my disk that moves my disk. in that i have given rotational speed for my disk. but if i make another cell zone condition for my disk and if i than give the mesh motion that means i am rotating my fluid at the disk position. !!!

Don't mix rotational speed at wall (BC) for a static mesh with rotional-sliding mesh (dynamic mesh)
In your case, if you want to move you rmesh you have to enable the dynamic mesh option, and you will set the rotor domain as moving with a rotational speed (not only the wall, but also the rotor --> that's why you disconnected the rotor from stator)

anbu2cfd April 1, 2014 00:49

Use sliding mesh interface,between your rotor and stator and specify the angular velocity for the disc. in cell zone conditions you have to enable the frame motion and copy those settings to mesh motion. interfaces should be define properly between the sliding. As max saying you can use dynamic mesh tool or sliding mesh to complete your task.

bhanu April 1, 2014 21:59

can you tell me how can i start dynamic mesh and what i have to do in that?

bhanu April 1, 2014 22:03

can you tell me how can i give rotational speed in dynamic mesh???? there is no option such like that !!!!!!!


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