[Nek5000-users] linear stability tool

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

Hi Adam,

thank you, it works now.

However I still have a question about this tool. My base flow is time 
dependent, so I did in usrchk

call opcopy (u,v,w,vx,vy,vz)
u=u*function(time)
v=v*function(time)
w=w*function(time)

call gop(u,work,'+  ',n)
call gop(v,work,'+  ',n)
call gop(w,work,'+  ',n)

do e=1,nelv
    eg = lglel(e)
    call copy(vx(1,1,1,e),u(1,1,1,eg),nxyz)
    call copy(vy(1,1,1,e),v(1,1,1,eg),nxyz)
    call copy(vz(1,1,1,e),w(1,1,1,eg),nxyz)
enddo

However, I am not sure how to specify this velocity filed as the base 
flow each time step...

Thank you in advance.
SL

El 15-03-2016 19:06, nek5000-users at lists.mcs.anl.gov escribió:
> Hi
> 
> To force base flow to be constant you have to set negative param(31)
> in your ###.rea file. Something like
>    -1.00000     p031 NPERT: #perturbation modes
> Of course you need the base flow as well. It could be analytical one
> set in useric, or just a field read during initialisation.
> Regards
> Adam
> 
> 
> On 2016-03-15 08:49, nek5000-users at lists.mcs.anl.gov wrote:
>> Hi Neks,
>> 
>> I'm trying to use the linear stability tool of Nek5000.
>> 
>> To start with, I am trying to run the ext_cyl example. However, I have 
>> found the following problem:
>> 
>> ERROR: arnoldi assumes constant base flow.
>> 
>> I have found on the README tutorial that the base flow has to be 
>> specified on the .rea file. I have included a file in the 
>> PRESOLVE/RESTART option, however I still have the same error.
>> 
>> What should I modify?
>> 
>> Finally, I have also used a subroutine defined in the .usr file that 
>> reads the file containing the base flow. However, the error persist...
>> 
>> Could you help me, please?
>> 
>> Cheers
>> SL
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> 
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