Using vorticity utility and meaning of curl (U)
 

Dear Foamers,

I am planing to use vorticity as a post processing utility. When I hit the vorticity command in terminal the error comes up:

Time = 1500
Reading U
Calculating vorticity
--> FOAM Warning :
--> FOAM FATAL IO ERROR:
keyword curl(U) is undefined in dictionary "/home/ali/run/2/system/fvSchemes::gradSchemes"


1. Is there any body explain me what the curl(U) is?
2. Is there any suggestion for the most suitable gradSchemes for curl(U) in fvSchemes?

I really appreciate for any help.

1. Curl(U) is the cross product of the vector differential operator and the velocity vector explained here

2. for grad schemes, I like least squares defined like
found from here

Enjoy

hi foamers
I have the same problem as aligoger. Did anybody solve this problem?

best

Greetings to all!

@gaza:
What Daniel meant is that you should edit the file "system/fvSchemes" and find the block that starts with "gradSchemes", e.g.:
And add the entry for "curl(U)":
Best regards,
Bruno

Hi Bruno
In fvScheme I had set up
gradSchemes
{
default none;
grad(p) Gauss linear;
grad(U) Gauss linear;
}

Today when I changed this to
gradSchemes
{
default Gauss linear;
// grad(p) Gauss linear;
// grad(U) Gauss linear;
}
it works. I don't know why and this is strange for me.
I haven't had to set up curl(U).
Very thank you for your ultra fast replay and help.

best
Przemek

It seems that settings: default none
in gradSchemes cannot be set up if I want to calculate vorticity
with vorticity utility.

best
Przemek