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Using vorticity utility and meaning of curl (U)

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Old   June 18, 2013, 11:13
Default Using vorticity utility and meaning of curl (U)
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Ali
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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.
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Old   June 19, 2013, 14:58
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Daniel P. Combest
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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
Code:
grad(U) leastSquares;
found from here

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Old   September 27, 2013, 15:34
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hi foamers
I have the same problem as aligoger. Did anybody solve this problem?

best
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Old   September 27, 2013, 21:01
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Bruno Santos
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Greetings to all!

@gaza:
Quote:
Originally Posted by gaza View Post
I have the same problem as aligoger. Did anybody solve this problem?
What Daniel meant is that you should edit the file "system/fvSchemes" and find the block that starts with "gradSchemes", e.g.:
Code:
gradSchemes
{
    default         Gauss linear;
    grad(p)         Gauss linear;
}
And add the entry for "curl(U)":
Code:
gradSchemes
{
    default         Gauss linear;
    grad(p)         Gauss linear;
    curl(U) leastSquares;
}
Best regards,
Bruno

Last edited by wyldckat; September 27, 2013 at 21:02. Reason: grad(U) -> curl(U)
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Old   September 28, 2013, 01:42
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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
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Old   September 28, 2013, 01:50
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It seems that settings: default none
in gradSchemes cannot be set up if I want to calculate vorticity
with vorticity utility.

best
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