[GAMBIT] Rotating Circle in a parrallel plate

MrinalKR · October 19, 2012, 08:59

Hi friends

I want to rotate a circle(solid) inside a rectangular domain(fluid). what type of mesh have to create. I'm using gambit for meshing and solver fluent. Please help.

-mAx- · October 22, 2012, 00:52

is it 2d?
will your circle rotate (moving mesh) or is it steady state problem?

MrinalKR · October 22, 2012, 00:58

My problem is 2D and transient. Initially i want to rotate the circle then i have to implement translation motion also. Now i'm concentrating only on rotation.

-mAx- · October 22, 2012, 01:18

*create your rectangle
*create your disk
*place your disk on its right position.
*split the rectangle with your disk
*copy the disk anywhere with a translation vector
*delete the initial disk (check with shaded mode that your rectangle has an hollow in place of the disk)
*define the circle edges (from rectangle) as interface
*define the circle edges (from copied disk) as interface
*move the copied disk with opposite translation vector back
*define the disk domain as fluid continuum
*define your other BC
*mesh
*export
That's it for Gambit side

MrinalKR · October 22, 2012, 01:44

Thank you..
I'll follow the procedure.

MrinalKR · October 22, 2012, 02:01

you told that "define the disk domain as fluid continuum".
Actually my rotating body is solid so i should be defined the disk domain as solid and the rectangular domain to be fluid?? is it correct??

MrinalKR · October 22, 2012, 02:06

Can i use any type of meshing (structured or unstructured) for circular and rectangular domain ?

-mAx- · October 22, 2012, 02:52

you can choose any kind of mesh, is it only your choice.
Ok then is your disk is solid, you are rightm you disk will appear as hollow since no NS-equations will be solved.
Than you can create a circle with greater radius than solid-disk, and split the rectangle.
And you do the same as previously explained but with an annulus

MrinalKR · October 22, 2012, 03:14

Sorry..
i didn't understand what you have told may be because I'm new to moving mesh and FSI idea.

-mAx- · October 22, 2012, 03:22

*create your rectangle
*create your disk
*place your disk on its right position.
*split the rectangle with your disk
*delete the initial disk (check with shaded mode that your rectangle has an hollow in place of the disk)
*create a circle with radius greater than solid-disk (create and move at right place)
*split the previous domain with the new circle (it will create an annulus around your solid disk which is hollowed)
*copy the annulus anywhere with a translation vector
*delete the annulus surface
*define the circle edges (from rectangle) as interface
*define the outer-circle edges (from copied annulus) as interface
*move the copied annulus with opposite translation vector back
*define the annulus domain as fluid continuum
*define your other BC
*mesh
*export

MrinalKR · October 22, 2012, 03:46

Thank you so much.. :-)
i'll follow the procedure..

MrinalKR · October 22, 2012, 03:51

Can we use boundary layer meshing instead of creating annulus region?? i have seen one tutorial of concentric cylinder rotating. In that they used boundary layer meshing. But i didnt get the complete tutorial. So i dont know for what purpose they have used.

-mAx- · October 22, 2012, 03:56

you can also attach a BL on the inner-circle from annulus (this is par of meshing)

If you don't want to move you mesh (sliding mesh), then forget all points after "*delete the initial disk ".
And then you will have to set the circle as wall BUT with a velocity,
And off course you won't see you grid moving

MrinalKR · October 22, 2012, 05:04

thank you very much for clearing the doubts and helping.. :-)

rshbhb · October 22, 2012, 17:49

Dear MAx,

Hello Sir/Ma'am.
I want to make the kind of geometry as shown in the image (attached) in the gambit software. I believe that you can help me.

Awaiting your reply soon.

Thank you.

MrinalKR · October 23, 2012, 00:35

In my case the clearance between circle and walls of the rectangle is very less (.1 to .3mm). In this case how can i mesh??

-mAx- · October 23, 2012, 01:23

Quote:

Originally Posted by rshbhb

Dear MAx,

Hello Sir/Ma'am.
I want to make the kind of geometry as shown in the image (attached) in the gambit software. I believe that you can help me.

Awaiting your reply soon.

Thank you.

Please open a new thread with your request (I will reply)

-mAx- · October 23, 2012, 01:24

Quote:

Originally Posted by MrinalKR

In my case the clearance between circle and walls of the rectangle is very less (.1 to .3mm). In this case how can i mesh??

Post a picture

MrinalKR · October 23, 2012, 01:29

Please find the attachment.

-mAx- · October 23, 2012, 01:33

decrease circle's radius, else you will have skewness problem

October 19, 2012, 08:59	Rotating Circle in a parrallel plate	#1
MrinalKR Member Mrinal K R Join Date: Sep 2011 Location: Chennai, India Posts: 47 Rep Power: 14	Hi friends I want to rotate a circle(solid) inside a rectangular domain(fluid). what type of mesh have to create. I'm using gambit for meshing and solver fluent. Please help.

October 22, 2012, 00:52		#2
-mAx- Super Moderator Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,297 Rep Power: 41	is it 2d? will your circle rotate (moving mesh) or is it steady state problem? MrinalKR likes this. __________________ In memory of my friend Hervé: CFD engineer & freerider

October 22, 2012, 01:18		#4
-mAx- Super Moderator Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,297 Rep Power: 41	create your rectangle create your disk place your disk on its right position. split the rectangle with your disk copy the disk anywhere with a translation vector delete the initial disk (check with shaded mode that your rectangle has an hollow in place of the disk) define the circle edges (from rectangle) as interface define the circle edges (from copied disk) as interface move the copied disk with opposite translation vector back define the disk domain as fluid continuum define your other BC mesh *export That's it for Gambit side MrinalKR likes this. __________________ In memory of my friend Hervé: CFD engineer & freerider

October 22, 2012, 02:52		#8
-mAx- Super Moderator Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,297 Rep Power: 41	you can choose any kind of mesh, is it only your choice. Ok then is your disk is solid, you are rightm you disk will appear as hollow since no NS-equations will be solved. Than you can create a circle with greater radius than solid-disk, and split the rectangle. And you do the same as previously explained but with an annulus __________________ In memory of my friend Hervé: CFD engineer & freerider

October 22, 2012, 03:22		#10
-mAx- Super Moderator Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,297 Rep Power: 41	create your rectangle create your disk place your disk on its right position. split the rectangle with your disk delete the initial disk (check with shaded mode that your rectangle has an hollow in place of the disk) create a circle with radius greater than solid-disk (create and move at right place) split the previous domain with the new circle (it will create an annulus around your solid disk which is hollowed) copy the annulus anywhere with a translation vector delete the annulus surface define the circle edges (from rectangle) as interface define the outer-circle edges (from copied annulus) as interface move the copied annulus with opposite translation vector back define the annulus domain as fluid continuum define your other BC mesh export MrinalKR likes this. __________________ In memory of my friend Hervé: CFD engineer & freerider

October 22, 2012, 00:58		#3
MrinalKR Member Mrinal K R Join Date: Sep 2011 Location: Chennai, India Posts: 47 Rep Power: 14	My problem is 2D and transient. Initially i want to rotate the circle then i have to implement translation motion also. Now i'm concentrating only on rotation.

October 22, 2012, 01:44		#5
MrinalKR Member Mrinal K R Join Date: Sep 2011 Location: Chennai, India Posts: 47 Rep Power: 14	Thank you.. I'll follow the procedure.

October 22, 2012, 02:01		#6
MrinalKR Member Mrinal K R Join Date: Sep 2011 Location: Chennai, India Posts: 47 Rep Power: 14	you told that "define the disk domain as fluid continuum". Actually my rotating body is solid so i should be defined the disk domain as solid and the rectangular domain to be fluid?? is it correct??

October 22, 2012, 02:06		#7
MrinalKR Member Mrinal K R Join Date: Sep 2011 Location: Chennai, India Posts: 47 Rep Power: 14	Can i use any type of meshing (structured or unstructured) for circular and rectangular domain ?

October 22, 2012, 03:14		#9
MrinalKR Member Mrinal K R Join Date: Sep 2011 Location: Chennai, India Posts: 47 Rep Power: 14	Sorry.. i didn't understand what you have told may be because I'm new to moving mesh and FSI idea.

October 22, 2012, 03:46		#11
MrinalKR Member Mrinal K R Join Date: Sep 2011 Location: Chennai, India Posts: 47 Rep Power: 14	Thank you so much.. :-) i'll follow the procedure..

October 22, 2012, 03:51		#12
MrinalKR Member Mrinal K R Join Date: Sep 2011 Location: Chennai, India Posts: 47 Rep Power: 14	Can we use boundary layer meshing instead of creating annulus region?? i have seen one tutorial of concentric cylinder rotating. In that they used boundary layer meshing. But i didnt get the complete tutorial. So i dont know for what purpose they have used.

October 22, 2012, 03:56		#13
-mAx- Super Moderator Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,297 Rep Power: 41	you can also attach a BL on the inner-circle from annulus (this is par of meshing) If you don't want to move you mesh (sliding mesh), then forget all points after "*delete the initial disk ". And then you will have to set the circle as wall BUT with a velocity, And off course you won't see you grid moving MrinalKR likes this. __________________ In memory of my friend Hervé: CFD engineer & freerider

October 22, 2012, 05:04		#14
MrinalKR Member Mrinal K R Join Date: Sep 2011 Location: Chennai, India Posts: 47 Rep Power: 14	thank you very much for clearing the doubts and helping.. :-)

October 23, 2012, 00:35		#16
MrinalKR Member Mrinal K R Join Date: Sep 2011 Location: Chennai, India Posts: 47 Rep Power: 14	In my case the clearance between circle and walls of the rectangle is very less (.1 to .3mm). In this case how can i mesh??

October 23, 2012, 01:33		#20
-mAx- Super Moderator Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,297 Rep Power: 41	decrease circle's radius, else you will have skewness problem __________________ In memory of my friend Hervé: CFD engineer & freerider

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