[ICEM] J-Type grid

Far · February 10, 2012, 16:40

Hi Folks

Previously I tried several times to create the J-type mesh for turbomachinery using ICEM. with no success. http://www.cfd-online.com/Forums/ans...ine-blade.html

Finally I found a method to do so and wanted to share with you. Geometry is simple with leading edge type shape.

Picture of final mesh

Steps to create this topology(1-5):

Far · February 10, 2012, 16:45

steps 6-9

Far · February 11, 2012, 08:42

Use of shifted periodic to define the periodic boundary conditions

Steps : 10-13

Far · February 11, 2012, 08:47

Since latest version of Fluent has option for non conformal periodic boundary conditions. Therefore it is not always required to define the periodicity in ICEM and also there is no need to use the shifted periodic boundary condition. We shall create the non-conformal periodic boundary in Fluent. In ICEM define per1 and per2 as interface boundaries.

PS : Fluent V 12 and ICEM V 12 are used for all this work

steps 14-16

PSYMN · February 14, 2012, 14:16

Why not just apply a CGrid or Quarter Ogrid on this...

Maybe I am not understanding your goal, but I think you could have got all the hard part done in one quick top down procedure. Oh well.

Far · February 14, 2012, 15:36

I dont think that this is possible with quarter O-grid

PSYMN · February 15, 2012, 15:17

The first 9 steps can be replaced by 2 simple splits, a quarter ogrid and one delete block. You will get to the same blocking, but the index will be much cleaner.

I didn't understand what you were trying to accomplish with steps 10 thru 13... I guess this is a periodic model and you were trying to create a shifted periodic blocking? Just put a quarter Ogrid the other way, then apply periodic verts and be done.

Jonathan · February 12, 2013, 05:12

hi FAR.

thanks for your post - I think the Numeca mesher uses J-grids quite extensively.

Just a quick question though, were you able to make conformal periodics with this mesh?

I am trying to stay away from quarter o-grids since I often end up with a block of dense cells in the quarter o-grid and which then gives me mesh related issues with variables which are highly sensitive to mesh density!

Again thanks for posting this -

Best regards
Jonathan

February 10, 2012, 16:40	J-Type topology,shifted and non shifted periodicity	#1
Far Senior Member Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,558 Blog Entries: 6 Rep Power: 54	Hi Folks Previously I tried several times to create the J-type mesh for turbomachinery using ICEM. with no success. http://www.cfd-online.com/Forums/ans...ine-blade.html Finally I found a method to do so and wanted to share with you. Geometry is simple with leading edge type shape. Picture of final mesh Steps to create this topology(1-5): Last edited by Far; February 11, 2012 at 08:50. Reason: Title change

February 11, 2012, 08:42	Shifted periodic	#3
Far Senior Member Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,558 Blog Entries: 6 Rep Power: 54	Use of shifted periodic to define the periodic boundary conditions Steps : 10-13

February 11, 2012, 08:47	Nonconformal periodicity treatment	#4
Far Senior Member Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,558 Blog Entries: 6 Rep Power: 54	Since latest version of Fluent has option for non conformal periodic boundary conditions. Therefore it is not always required to define the periodicity in ICEM and also there is no need to use the shifted periodic boundary condition. We shall create the non-conformal periodic boundary in Fluent. In ICEM define per1 and per2 as interface boundaries. PS : Fluent V 12 and ICEM V 12 are used for all this work steps 14-16

February 14, 2012, 14:16		#5
PSYMN Senior Member Simon Pereira Join Date: Mar 2009 Location: Ann Arbor, MI Posts: 2,663 Blog Entries: 1 Rep Power: 47	Why not just apply a CGrid or Quarter Ogrid on this... Maybe I am not understanding your goal, but I think you could have got all the hard part done in one quick top down procedure. Oh well. __________________ ----------------------------------------- Please help guide development at ANSYS by filling in these surveys Public ANSYS ICEM CFD Users Survey This second one is more general (Gambit, TGrid and ANSYS Meshing users welcome)... CFD Online Users Survey

February 15, 2012, 15:17		#7
PSYMN Senior Member Simon Pereira Join Date: Mar 2009 Location: Ann Arbor, MI Posts: 2,663 Blog Entries: 1 Rep Power: 47	The first 9 steps can be replaced by 2 simple splits, a quarter ogrid and one delete block. You will get to the same blocking, but the index will be much cleaner. I didn't understand what you were trying to accomplish with steps 10 thru 13... I guess this is a periodic model and you were trying to create a shifted periodic blocking? Just put a quarter Ogrid the other way, then apply periodic verts and be done. __________________ ----------------------------------------- Please help guide development at ANSYS by filling in these surveys Public ANSYS ICEM CFD Users Survey This second one is more general (Gambit, TGrid and ANSYS Meshing users welcome)... CFD Online Users Survey

February 10, 2012, 16:45		#2
Far Senior Member Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,558 Blog Entries: 6 Rep Power: 54	steps 6-9

February 14, 2012, 15:36		#6
Far Senior Member Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,558 Blog Entries: 6 Rep Power: 54	I dont think that this is possible with quarter O-grid

February 12, 2013, 05:12		#8
Jonathan Senior Member Join Date: Mar 2010 Posts: 181 Rep Power: 17	hi FAR. thanks for your post - I think the Numeca mesher uses J-grids quite extensively. Just a quick question though, were you able to make conformal periodics with this mesh? I am trying to stay away from quarter o-grids since I often end up with a block of dense cells in the quarter o-grid and which then gives me mesh related issues with variables which are highly sensitive to mesh density! Again thanks for posting this - Best regards Jonathan

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