[Nek5000-users] Periodic BC on non-parallel boundaries

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

David,

What do you mean by "remapping a periodic-side domain in userdat2"?

Sure, even with IFCYCLIC=F you'll get a result. But is probably not
the one you had in mind, simply because the BCs are different i.e.
periodic vs cyclic.

-Stefan

On 10/11/11, nek5000-users at lists.mcs.anl.gov
<nek5000-users at lists.mcs.anl.gov> wrote:
> Hi Stefan,
>
> I`ve got another question related to the periodic/cyclic BC`s.  In addition
> to the partial 2D annulus, I`m also trying to simulate a 3D annular cylinder
> (a full 2π radians for now).  I made the domain as I made the full 2D
> annulus, by remapping a periodic-side domain in userdat2.  This worked in
> 2D, but in 3D the periodic BC are not working properly.  Is this a case
> where cyclic BC would be needed, rather than periodic?  I`m hoping not since
> I have stress-free walls, so I`m using Pn/Pn-2 again.  (I tried the same
> setup with no-slip BC in the Pn/Pn formulation, and that did work properly.)
>
> Thanks,
>
> David
>
> P.S. When I tried the 2D partial-annulus case with Pn/Pn, I accidentally had
> IFCYCLIC=F one time, and it still worked, so I can`t tell whether the cyclic
> feature is having an effect at all.
>
>
> On Mon, Oct 10, 2011 at 2:20 PM, <nek5000-users at lists.mcs.anl.gov> wrote:
>
>> Hmm, just had a look at the code. It looks to me that it might work
>> out of the box. Why don't you give it a shot.
>>
>> Cheers
>> Sefan
>>
>> On 10/10/11, S K <stgeke at googlemail.com> wrote:
>> > Let me check what we need to change to make it happen.
>> > -Stefan
>> >
>> > On 10/10/11, nek5000-users at lists.mcs.anl.gov
>> > <nek5000-users at lists.mcs.anl.gov> wrote:
>> >> Well then it seems I am stuck.  Might a work-around be possible for a
>> 1/4
>> >> or
>> >> 1/2 annulus?  For instance with 1/2, I would just need to match (u,v)
>> >> to
>> >> (-u,-v).
>> >>
>> >> David
>> >>
>> >> On Mon, Oct 10, 2011 at 1:41 PM, <nek5000-users at lists.mcs.anl.gov>
>> wrote:
>> >>
>> >>> btw: I am afraid, the stress formulation doesn't support cyclic BCs at
>> >>> the moment!
>> >>> -Stefan
>> >>>
>> >>> On 10/10/11, S K <stgeke at googlemail.com> wrote:
>> >>> > You are right, it's an undocumented AND experimental feature. Just
>> >>> > flag the boundaries as periodic. Yes, just add another IFCYCLIC
>> >>> > line.
>> >>> > Currently, there is no stress formulation support for Pn/Pn.
>> >>> >
>> >>> > -Stefan
>> >>> >
>> >>> > On 10/10/11, nek5000-users at lists.mcs.anl.gov
>> >>> > <nek5000-users at lists.mcs.anl.gov> wrote:
>> >>> >> Hi Stephan,
>> >>> >>
>> >>> >> I see, thanks.  I can`t find any documentation about cyclic BC`s.
>> >>> >> What
>> >>> >> is
>> >>> >> their symbol for the box file?  Also, I don`t see a logical switch
>> >>> >> for
>> >>> >> IFCYCLIC.  Do I just add another line?
>> >>> >>
>> >>> >> Also, I have stress-free BC on curved boundaries.  A series of
>> >>> >> error
>> >>> >> messages led me to believe that I had to use the stress
>> >>> >> formulation,
>> >>> >> and
>> >>> >> that this required me to use Pn/Pn-2.  Is this not the case?
>> >>> >>
>> >>> >> Best,
>> >>> >>
>> >>> >> David
>> >>> >>
>> >>> >
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>> >
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