CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   ANSYS Meshing & Geometry (http://www.cfd-online.com/Forums/ansys-meshing/)
-   -   Spacing value in ICEM CFD (http://www.cfd-online.com/Forums/ansys-meshing/92692-spacing-value-icem-cfd.html)

avi031 September 22, 2011 03:04

Spacing value in ICEM CFD
 
Hello all,

I want to know what is meant by "Spacing" in Edge parameters box in ICEM CFD. I know it is for biasing the mesh. Is there a way to correlate the value for 'spacing' in ICEM CFD with Y+ value?
If Y+ value should be less than 1, then what would be the appropriate value for 'Spacing'? Please let me know...

Regards
Avinash

BrolY September 22, 2011 05:07

For a geometric 1 law, if you specify a spacing of 1, the length between the two first nodes would be of 1. After, it depends on the ratio.

The Y+ is not the spacing. The Y+ depends on your turbulence model. The spacing will be the value of the height of your first boundary layer.

About the height of your first boundary layer, you have to calculate it by yourself. Most of the solvers give you the formula which is used by the code. It depends on your turbulence model, velocity, geometry and fluid specifications.

avi031 September 22, 2011 06:02

BrolY,

Thank you for the reply.......Do you mean to say that the Y+ value will vary with turbulence model????

BrolY September 22, 2011 07:01

What I mean is the Y+ range depends on the turbulecne model. For example :
For a Rij-Epsilon model, a Y+ between 30 and 200 is recommanded.
For a k-omega model, a Y+ between 1 and 10 is recommanded.

plabon0709 July 21, 2013 00:13

Quote:

Originally Posted by BrolY (Post 325208)
What I mean is the Y+ range depends on the turbulecne model. For example :
For a Rij-Epsilon model, a Y+ between 30 and 200 is recommanded.
For a k-omega model, a Y+ between 1 and 10 is recommanded.

Then what do is the meaning of y+ value 1....all the expert says y + value 1 is batter.then why it will be 30 to 300

PSYMN July 22, 2013 13:47

We would like to use an infinite number of elements and solve it in no time... But instead we make compromises. A Y+ of 1 would be great if you have the time and resources, but solvers put a lot of emphasis on doing more with less.


All times are GMT -4. The time now is 00:06.