[Nek5000-users] Error in generalev with MHD

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

Hey,
thanks for the suggestions.
I want to change some of the boundarie values to values =!0 for the 
actual simulations, that's why there is a mix of small and capital V's. 
However, userbc sets the bc to zero. I will try to use only one of the 
two, in case there is a problem with mixing v and V.
As far as I know, the specification for the Element-Element-Boundary (E) 
you mentioned is outdated and handled by the solver. I have run several 
hydrodynamic simulations with 0 for the options and never encountered 
any problems.

Am 01.07.14 14:51, schrieb nek5000-users at lists.mcs.anl.gov:
> Hi Jan,
>
> On line 5912, velocity BC is written with capital letter V instead of 
> small letter v (as in 5928).
>
> If you write velocity with small letter, it'll read the BC in the .usr 
> file (userbc subroutine), otherwise you have to specify the values of 
> velocity in the .rea file.
>
> In addition, in the elements (E) BC you have to specify
>
> E     n1    n2   n3   n4   0  0  0
> n1: Number of element
> n2: side of element
> n3: element connected
> n4: side of the element connected.
>
> However, you've set n3 and n4 to 0.
>
> I hope it helps you.
>
> Regards,
> SL
>
>
>
> El 01-07-2014 13:56, nek5000-users at lists.mcs.anl.gov escribió:
>> Hello Neks,
>> I' trying to solve the MHD equations and encounter the same error 
>> reported here:
>> http://lists.mcs.anl.gov/pipermail/nek5000-users/2011-June/001365.html.
>> For testing, I have set up a small grid (384 elements) with B=0 at the
>> boundaries and B=0 as initial conditions, and the error appears before
>> the first timestep. As mentioned in the documentation, I have used the
>> same BC-types for the B Field as for the velocity, so in the .rea file
>> it reads:
>>
>> 5909   ***** PASSIVE SCALAR 1  BOUNDARY CONDITIONS *****
>> 5910  E    1  1   0.00000       0.00000       0.00000 0.00000       
>> 0.00000
>> 5911  E    1  2   0.00000       0.00000       0.00000 0.00000       
>> 0.00000
>> 5912  V    1  3   0.00000       0.00000       0.00000 0.00000       
>> 0.00000
>> 5913  E    1  4   0.00000       0.00000       0.00000 0.00000       
>> 0.00000
>> 5914  E    1  5   0.00000       0.00000       0.00000 0.00000       
>> 0.00000
>> 5915  E    1  6   0.00000       0.00000       0.00000 0.00000       
>> 0.00000
>> 5916  E    2  1   0.00000       0.00000       0.00000 0.00000       
>> 0.00000
>> 5917  E    2  2   0.00000       0.00000       0.00000 0.00000       
>> 0.00000
>> 5918  E    2  3   0.00000       0.00000       0.00000 0.00000       
>> 0.00000
>> 5919  E    2  4   0.00000       0.00000       0.00000 0.00000       
>> 0.00000
>> 5920  E    2  5   0.00000       0.00000       0.00000 0.00000       
>> 0.00000
>> 5921  E    2  6   0.00000       0.00000       0.00000 0.00000       
>> 0.00000
>> 5922  E    3  1   0.00000       0.00000       0.00000 0.00000       
>> 0.00000
>> 5923  E    3  2   0.00000       0.00000       0.00000 0.00000       
>> 0.00000
>> 5924  E    3  3   0.00000       0.00000       0.00000 0.00000       
>> 0.00000
>> 5925  E    3  4   0.00000       0.00000       0.00000 0.00000       
>> 0.00000
>> 5926  E    3  5   0.00000       0.00000       0.00000 0.00000       
>> 0.00000
>> 5927  E    3  6   0.00000       0.00000       0.00000 0.00000       
>> 0.00000
>> 5928  v    4  1   0.00000       0.00000       0.00000 0.00000       
>> 0.00000
>> 5929  E    4  2   0.00000       0.00000       0.00000 0.00000       
>> 0.00000
>> 5930  E    4  3   0.00000       0.00000       0.00000 0.00000       
>> 0.00000
>> etc.
>>
>> The thread above mentioned that it was due to incorrect BCs, but
>> unfortunately no more details were given.
>>
>> Cheers,
>> Jan
>>
>> _______________________________________________
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>
>
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