CFD Online Discussion Forums

CFD Online Discussion Forums (
-   CFX (
-   -   Inflation (

Gab August 9, 2005 18:52

Hi, All

I try to use inflation in meshing. The problem I got is that I can only creat inflation layers on certain faces in my geometry. If I choose more or all the faces, it did not show error but gave me no inflation layers.

I tried many times but still haven't figure out the rules of using inflation.

Can someone help provide me some tips on using inflation? Is it possible/necessary to generate inflation layers on all faces?


Best regards!


Gab August 10, 2005 10:06

Re: Inflation
Sorry, I am using cfx-mesh.



Paul Lewis August 10, 2005 15:54

Re: Inflation
Hi Gab,

The use of inflation layers in the near wall region creates cells that are aligned to the direction of the flow (i.e. along the wall). If possible, it's best to use 10-15 layers in the boundary layer region. Using the settings in CFX mesh you can fine tune the thickness of the layers. The layer nearest the wall needs to be changed until you get a y-plus figure of the correct magnitude for the turbulence model you are using. Scaleable wall functions mean that result should be independent of y-plus lower than 11. The outer layer should be of a similar thickness to the "default body spacing", this ensures there is no sudden change in cell size at the edge of the inflated layer.

I have had problems in the past creating inflation layers on multiple surfaces. Try not to select the composite surfaces from the tree, instead select each surface directly from the model using the mouse.

Good Luck


Gab August 10, 2005 23:52

Re: Inflation
Thanks, Paul

I tried as you suggested. It works for some faces, but not all. I check the cfx-mesh help file, it says that 'Inflation can be applied to all ordinary boundaries but not to boundaries specified as a Periodic Pair'. So I suppose that the inflation function should works for all the faces in my mesh.

I also observed that the problem comes whereever three adjoining faces (for example three adjoining faces of a box)were defined as inflation. What can I do in such cases?




Gab August 11, 2005 02:16

Re: Inflation
I have solve the problem. The inflation layers actually were there, I just was not able to view them from surface mesh.



Helper August 11, 2005 04:17

Re: Inflation
Try changing the Preview setting - "Display Mesh" to "Inflated Mesh" and then only the prismatic/inflated mesh will be displayed.

Hamid August 24, 2005 22:45

Re: Inflation
hi dear you have selected the face that belong to fluid side which means that the face you have there to inflate belongs to a solid domain. supress those bodies that you don't need then chose the face that you need the iflation to grow with in it. let me how you did. Rgards Hamid

All times are GMT -4. The time now is 09:40.