[ok___ko]

HI,

I need to change the y+ value more smaller, how could I do it?

Thanks in advance

[Aeronautics El. K.]

Place the first grid point closer to the surface

[ok___ko]

Dear Lefteris,

thanks for your quick reply, do you mean I need to minimize the spacing of the edage which is near the wall?

And when I adapt the y+value, and set the value, but when I xy-plot it, it is still larger than 1. Do you know why?

[Aeronautics El. K.]

Yeap, minimise this edge by placing the first grid point as close to the wall as possible (as close as you need actually).
I don't really understand what you mean when you say "when I xy-plot it" (you mean you plot y+ ?) but y+ depends upon other parameters as well which you can only estimate beforehand and know their value only after the computations are completed.

[ok___ko]

Originally Posted by Aeronautics El. K.

Yeap, minimise this edge by placing the first grid point as close to the wall as possible (as close as you need actually).
I don't really understand what you mean when you say "when I xy-plot it" (you mean you plot y+ ?) but y+ depends upon other parameters as well which you can only estimate beforehand and know their value only after the computations are completed.

Well, thanks, I do just you said, the aspect ratio has also beed reduced, but the y+ value on the right wall, it is still 9.

Do I need to creat a iso-surface that near the wall, or just choose the wall surface? If I need, which one do I need to keep surface constant?

One more problem, we have been a experimental data to compare, but the velocity from the xy-plot are not very close to the experimental one. Do you kown why?

Best regards

[RodriguezFatz]

If y+ = 9 and you want it to become y+=1 you need to make the first cell about 9 times finer than in your current grid.
In Fluent, you just need to plot y+ on the surface. It will use the first cell height for that!
For the last question you need to show us more about your setup / grid / settings and so on.

[ok___ko]

Originally Posted by RodriguezFatz

If y+ = 9 and you want it to become y+=1 you need to make the first cell about 9 times finer than in your current grid.
In Fluent, you just need to plot y+ on the surface. It will use the first cell height for that!
For the last question you need to show us more about your setup / grid / settings and so on.

IS that mean I need to refine it in ICEM in 'refinement'-level 9? IS that right? or need to minimize spacing 9 times smaller

[RodriguezFatz]

I am not sure what "refinement level 9" means. But if your first cell height is 1mm now, you need to reduce it to about 0.11mm.

[alireza9359300]

hi
change your mesh near the wall as small as you can and after check this parameter.

[Kent_Neo]

hi
use this tool to specify your mesh geometric parameters before your first calculation ,and i think there isn't an effective way to adjust your mesh (all y plus values) to the just condition.
http://geolab.larc.nasa.gov/APPS/YPlus/