[Nek5000-users] [*] Re: [*] Re: Postprocessing

[nek5000-users at lists.mcs.anl.gov]

Dear Paul,

     Does the code that you gave to output vorticity work for 2D too? 
I'm trying to simulate a lid driven cavity at Re=10000 and the velocity 
seems fine but nothing shows up on the vorticity plot (I've attached 
both of them).

Mani chandra

On 03/27/2010 06:13 PM, nek5000-users at lists.mcs.anl.gov wrote:
>
> Hi Mani,
>
> Nek currently supports only a few output fields:
>
> X, V, p, T, ps1, ... ,psn
>
> X = coords
> V = velocity
> p = pressure
> T = temperature
> psj = jth passive scalar
>
> The call
>
>        call outpost(vort(1,1),vort(1,2),vort(1,3),pr,t,'vrt')
>
> would generate a file "vrtmycase0.f..." with vorticity
> components in place of V=(vx,vy,vz).
>
> To view these with visit, load the vrt... file and request
> to look at "velocity"  (VisIt thinks the field is a velocity
> field).
>
> Paul
>
>
> On Sat, 27 Mar 2010, nek5000-users at lists.mcs.anl.gov wrote:
>
>> On 03/24/2010 09:58 PM, nek5000-users at lists.mcs.anl.gov wrote:
>>>
>>> Mani,
>>>
>>> It somewhat depends on what you're after.
>>>
>>> You can use postx and compute the vorticity there --- it is
>>> only 32 bit but it does allow you to compute the vorticity
>>> for any existing velocity data in the (older) .fld file
>>> output format.
>>>
>>> Alternatively, if you're using VisIt or some other analysis
>>> tool, or doing run-time analysis, you can compute the vorticity
>>> at runtime.  If you wish to output the vorticity field, you can
>>> do so, e.g., as follows:
>>>
>>> c----------------------------------------------------------------------- 
>>>
>>>       subroutine userchk
>>>       include 'SIZE'
>>>       include 'TOTAL'
>>>
>>>       parameter(lt=lx1*ly1*lz1*lelv)
>>>       common /scrns/ vort(lt,3),w1(lt),w2(lt)
>>>
>>>       if (mod(istep,iostep).eq.0) then
>>>          call comp_vort3(vort,w1,w2,vx,vy,vz)
>>>          call outpost(vort(1,1),vort(1,2),vort(1,3),pr,t,'vrt')
>>>       endif
>>>
>>>       return
>>>       end
>>> c----------------------------------------------------------------------- 
>>>
>>>
>>>
>>> This would generate an output "vrtmy_case..." if your .rea file is
>>> my_case.rea
>>>
>>> Any of the post-processing tools could then read the vrt.... files
>>> and treat the vorticity as the velocity vector field.
>>>
>>> As I say, not exactly sure what you have in mind, but this is one
>>> possible approach.
>>>
>>> Paul
>>>
>>>
>>>
>>>
>>>
>>> On Wed, 24 Mar 2010, nek5000-users at lists.mcs.anl.gov wrote:
>>>
>>>> Dear Nek devs,
>>>>
>>>>    I'm a bit confused regarding postprocessing. Is one supposed to 
>>>> run a simulation and then run nek5k again to load the fld files 
>>>> using load_fld() for postprocessing? Or can one compute the desired 
>>>> quantities after every time step using userchk() and then output 
>>>> them in a file? For example, how can I compute the vorticity using 
>>>> the differential operators defined in the code? After computing the 
>>>> vorticity, can it be outputted using the same fld files?
>>>>
>>>> Regards,
>>>> Mani chandra
>>>> _______________________________________________
>>>> Nek5000-users mailing list
>>>> Nek5000-users at lists.mcs.anl.gov
>>>> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
>>>>
>>> _______________________________________________
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>>>
>> Dear Paul,
>>
>>    The files generated by the code in usr_chk(), vrtmy_case0.f* do 
>> not seem to have vorticity in them when I view them in Visit through 
>> the database file. They only seem to have pressure, x, y, z 
>> components of velocity and the velocity magnitude. Could something be 
>> wrong?
>>
>> Mani chandra
>> _______________________________________________
>> Nek5000-users mailing list
>> Nek5000-users at lists.mcs.anl.gov
>> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
>>
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