How to Plot Eddies in Paraview :)
 

Hey All,

i am Trying to get eddies for LES case on my paraview in openFOAM

- i switched the contours on !! no help and i dunno where to go what to do get the eddies :D like the ones i have attached in the image

Please help

Thanks for your time :)

Hasan K.J

vortex detection criteria
 

Dear Hasan,

It depends on the vortex detection criteria. You may try using Q utility to generate second invariant of the velocity gradient tensor and visualize a contour of this field. Other option is using Lambda2 utility. But there are other vortex detection criteria as well. I hope this helps.

Zoltan

Where is Q utility and Lambda 2 utility
 

Hey Zoltan,

I am not able to find these two utilities the Q utility and Lambda 2 utility ?

- please can u tell where the option is in paraview ?
- i searched i am not able to locate it

Thanks :)

Regards,
Hasan K.J

hi
Execute the commands in terminal.

In addition to Ehsan's help, you might be interested in this list of OpenFOAM utilities:
http://openfoam.org/docs/user/standard-utilities.php

Hi hasan
could you see the vortices?could you attach them?
I used lambda2 and Q without sucess.not any vortices are displayed!

No... i havent tried it yet ? but does it actually make a difference if its LES or RAS case...?

i don't think it has a lot of effect on vortices.
what your opinion dear Zoltan?how could I set a contour for labda or Q?is the wide range normal in your opinion?

Lambda2 error
 

Hey guys,
My life is never simple and i will never get used to it :mad:

- i typed Q and it worked fine with my case :)
- then i typed Lambda2 and i get this error does any body know what this error means and whats causing it :)

- and Ehsan if you manage to get the eddies please let me know :)

Regards,
Hasan K.J.

and it works only for last time with some warning

Create mesh for time = 10000

Time = 10000
Reading U
--> FOAM Warning :
From function eigenValues(const tensor&)
in file primitives/Tensor/tensor/tensor.C at line 174
complex eigenvalues detected for tensor: (1902.57 7.65293e-07 -0.000402738 7.65293e-07 1902.57 3.34481e-05 -0.000402738 3.34481e-05 4.34386e-10)
--> FOAM Warning :
From function eigenValues(const tensor&)
in file primitives/Tensor/tensor/tensor.C at line 174
complex eigenvalues detected for tensor: (1902.57 7.65152e-07 -0.000250995 7.65152e-07 1902.57 2.85284e-05 -0.000250995 2.85284e-05 1.62937e-09)
--> FOAM Warning :
From function eigenValues(const tensor&)
in file primitives/Tensor/tensor/tensor.C at line 174
complex eigenvalues detected for tensor: (1902.57 7.65293e-07 0 7.65293e-07 1902.57 0 0 0 2.587e-09)
Writing -Lambda2

End

Create time

Create mesh for time = 0

Time = 0
Reading U
#0 Foam::error::printStack(Foam::Ostream&) in "/panfs/storage/local/non-commercial/OpenFOAM/OpenFOAM-SGISLES11-2.1.X_X8664_21JUNE12_REPO/OpenFOAM-2.1.x/platforms/linux64Gcc46DPOpt/lib/libOpenFOAM.so"
#1 Foam::sigFpe::sigHandler(int) in "/panfs/storage/local/non-commercial/OpenFOAM/OpenFOAM-SGISLES11-2.1.X_X8664_21JUNE12_REPO/OpenFOAM-2.1.x/platforms/linux64Gcc46DPOpt/lib/libOpenFOAM.so"
#2 in "/lib64/libc.so.6"
#3 acos in "/lib64/libm.so.6"
#4 Foam::eigenValues(Foam::Tensor<double> const&) in "/panfs/storage/local/non-commercial/OpenFOAM/OpenFOAM-SGISLES11-2.1.X_X8664_21JUNE12_REPO/OpenFOAM-2.1.x/platforms/linux64Gcc46DPOpt/lib/libOpenFOAM.so"
#5 Foam::eigenValues(Foam::Field<Foam::Vector<double> >&, Foam::UList<Foam::Tensor<double> > const&) in "/panfs/storage/local/non-commercial/OpenFOAM/OpenFOAM-SGISLES11-2.1.X_X8664_21JUNE12_REPO/OpenFOAM-2.1.x/platforms/linux64Gcc46DPOpt/lib/libOpenFOAM.so"
#6
in "/panfs/storage/local/non-commercial/OpenFOAM/OpenFOAM-SGISLES11-2.1.X_X8664_21JUNE12_REPO/OpenFOAM-2.1.x/platforms/linux64Gcc46DPOpt/bin/Lambda2"
#7
in "/panfs/storage/local/non-commercial/OpenFOAM/OpenFOAM-SGISLES11-2.1.X_X8664_21JUNE12_REPO/OpenFOAM-2.1.x/platforms/linux64Gcc46DPOpt/bin/Lambda2"
#8
in "/panfs/storage/local/non-commercial/OpenFOAM/OpenFOAM-SGISLES11-2.1.X_X8664_21JUNE12_REPO/OpenFOAM-2.1.x/platforms/linux64Gcc46DPOpt/bin/Lambda2"
#9
in "/panfs/storage/local/non-commercial/OpenFOAM/OpenFOAM-SGISLES11-2.1.X_X8664_21JUNE12_REPO/OpenFOAM-2.1.x/platforms/linux64Gcc46DPOpt/bin/Lambda2"
#10 __libc_start_main in "/lib64/libc.so.6"
#11
at /usr/src/packages/BUILD/glibc-2.11.3/csu/../sysdeps/x86_64/elf/start.S:116
Floating point exception

No Luck
 

Hey guys,

the maximum i can get to with my only working Q utility is this much
i tried contours with the Q selected nothing works ?

- if anybody manages to get it or know how to get it please help us :)

thanks

Regards,
Hasan K.J

how should set contour settings for a good figure?
its a test case.
whats the stages to see vortices contours?
thanks.

Greetings to all!

OK, using Ehsan's test case, here's what's going on: you are being blind-sighted by the maximum values. You need to change the scales down to lower values, such as [-200000, 200000], as shown in the 1st attached image.

If you don't know how to change the scale, read this post: http://www.cfd-online.com/Forums/ope...tml#post429974 - post #2.

As for contours, from the menu, choose "Filters -> Alphabetical -> Contour". Then configure as shown in the second image.

Best regards,
Bruno

hi, Alhasan
Have you solved the error with Lambda2? if so, please tell me how to solve it? thanks

Hi Youjing,

The problem i had was sorted when i put the right value for the Q criterion that i was trying to get on paraView

- First you use the Command and get the Q or Lambda2 from openFOAM

- then you paraView and select the contour botton and apply
- then select the Lambda2 within the Contour dialogue box
- then choose the right range or value, - if you dunno the right range play with the values till you get what you are looking for

All the Best,
Hasan K.J

Thanks for your fast reply, i think i can solve it now!:D:D