[Nek5000-users] solver tolerances and norm of residual

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

Hi,

I think this is not the reason because in a previous attempt to face the
3D problems I tried to solve the 3D lid-driven cavity (no periodic BC) and
I obtained the same error: NaN in Helholtz residual.

Maybe I should start from the turbChannel example and simplify the problem
to reach a laminar 3D poiseuille flow.

Anyway, thanks a lot for your answers.

> A quick look of the *rea file did not bring up anything.  I recall an
> issue with periodic BC's, following is an email from one of the
> developers:
>
>
> Hi Frank,
>
> Yes -- we currently don't support periodic bcs for
> anything smaller than a 3 x 3 x 3 array of elements.
>
> There's a technical reason for this --- it can be
> circumvented if really needed, but it would not
> fit within the std. context.
>
> Sorry about that.
>
> Paul
>
> On Tue, 2010-11-16 at 12:56 -0500, nek5000-users at lists.mcs.anl.gov
> wrote:
>> Hi Frank,
>>
>> The rea file has been attached.
>> Meanwhile I'll check the BC...
>>
>> Thanks
>>
>> > Hello Alex,
>> >
>> > I looked through your files & didn't see anything amiss (by the way,
>> it
>> > would be best to post your *.rea file).  Since it blows up on the
>> first
>> > attempt to solve for pressure, perhaps the BC's don't satisfy
>> > conservation of mass?
>> >
>> > Cheers,
>> > Frank
>> >
>> >
>> >
>> > On Tue, 2010-11-16 at 11:40 -0500, nek5000-users at lists.mcs.anl.gov
>> > wrote:
>> >
>> >> Hi Nek users,
>> >>
>> >> I am new in using Nek5. I have succesfully simualted the lid-driven
>> >> flow,
>> >> rayleigh-bénard in a square cavity and laminar poiseuille flow.
>> All of
>> >> them were 2d cases. I though it would be straightforward to move from
>> 2D
>> >> to 3D simualtions but I have not been able to run a 3D poiseuille
>> >> channel.
>> >> I am obtaining an error on Helmoltz solver even in the first
>> iteration.
>> >>
>> >> Please, find output, usr and box files attached.
>> >> Thanks in advance.
>> >>
>> >> ..........................................
>> >>            Alex Fabregat
>> >>         Post-doctoral fellow
>> >>         University of Ottawa
>> >> Department of Mechanical Engineering
>> >> _______________________________________________
>> >> Nek5000-users mailing list
>> >> Nek5000-users at lists.mcs.anl.gov
>> >> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
>> >
>> > --
>> > Frank Herbert Muldoon, Ph.D. Mechanical Engineering
>> > Technische Universität Wien (Vienna University of Technology)
>> > Inst. f. Strömungsmechanik und Wärmeübertragung (Institute of
>> Fluid
>> > Mechanics and Heat Transfer)
>> > Resselgasse 3
>> > 1040 Wien
>> > Tel: +4315880132232
>> > Fax: +4315880132299
>> > Cell:+436765203470
>> > fmuldoo (skype)
>> > http://tetra.fluid.tuwien.ac.at/fmuldoo/public_html/webpage/frank-muldoon.html
>> > _______________________________________________
>> > Nek5000-users mailing list
>> > Nek5000-users at lists.mcs.anl.gov
>> > https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
>> >
>>
>>
>> ..........................................
>>            Alex Fabregat
>>         Post-doctoral fellow
>>         University of Ottawa
>> Department of Mechanical Engineering
>> _______________________________________________
>> Nek5000-users mailing list
>> Nek5000-users at lists.mcs.anl.gov
>> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
> --
> Frank Herbert Muldoon, Ph.D. Mechanical Engineering
> Technische Universität Wien (Vienna University of Technology)
> Inst. f. Strömungsmechanik und Wärmeübertragung (Institute of Fluid
> Mechanics and Heat Transfer)
> Resselgasse 3
> 1040 Wien
> Tel: +4315880132232
> Fax: +4315880132299
> Cell:+436765203470
> fmuldoo (skype)
> http://tetra.fluid.tuwien.ac.at/fmuldoo/public_html/webpage/frank-muldoon.html
>
> _______________________________________________
> Nek5000-users mailing list
> Nek5000-users at lists.mcs.anl.gov
> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
>


..........................................
           Alex Fabregat
        Post-doctoral fellow
        University of Ottawa
Department of Mechanical Engineering