Learning Forum

[Dato]

Hi,

I use Custom Field Function and expression to define transverse flow intensity. But the contour of them is quite different. And the range of same location is largely different.

 

And the definition of transverse flow intensity defined in field function and expression are shown below. I think the definition may not be wrong so it's hard to explain the strange results.

Regards.

[Rob]

Deselect Node Values too, and then post those images. 

[Dato]

Hi Rob,

The images and ranges become same after I deselected node values.

1.Is it because the interpolation method different for Custom Field Function and Expression? 

2. I use Custom Field Function to define new variables because I just don't want to show unit under colormap.  Are there any ways not to display unit under the colormap except for using Custom Field Function in Fluent? 

3.  I want to make each words of  Custom Field Function name started with capital letter,  but I find that the letter of  new Custom Field Function name cannot be capitalized. Can I make it in some ways?

Best regars.

LEE

[Rob]

CFFs are an older way of interacting with the solver, and are VERY linked into both Scheme and Unix rules. As Unix is case sensitive you'll find many of Fluent's functions don't allow upper case, you can't use spaces either. 

Contours use smoothing to improve the images. If the mesh is very well resolved you'll not see the difference between node values on and off. However, CFFs may well interact with the data in a slightly different way to expressions. The solver is using/reporting the correct value, it's an image smoothing effect that you're seeing. 

[Dato]

Thanks you so much, sir. It's quite helpful to understand Fluent. 

[Rob]

You're welcome. It's very helpful to understand Fluent, but after over 25 years of using it at various levels I'm still a way off that!