[Nek5000-users] SYM and ON boundary conditions

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

Yes, the SYM conditions make sense. The pressure boundary terms vanish in
the weak formulation as do the viscous boundary terms. I suppose u.n = 0 is
imposed strongly while (grad(u).n).t = 0 is imposed weakly. These two
together imply that grad(p).n = 0 (using the momentum eqn and zero
divergence condition).

Is the implementation of "ON" different from "O". Otherwise I dont see the
need for two different types ?

Thanks
praveen

On Fri, Oct 24, 2014 at 10:05 PM, <nek5000-users at lists.mcs.anl.gov> wrote:

>  Hi Praveen,
>
> I think 'ON' is the same as O for the n direction, and Dirichlet for the
> t
> directions.
>
> Concerning the SYM you are right it is (grad(u).n).t, it may be better to
> not have it in vector notation at all. However I don't think there is a
> condition on the pressure, but I guess one could check in the code.
>
> Oana
>  ------------------------------
> *From:* nek5000-users-bounces at lists.mcs.anl.gov [
> nek5000-users-bounces at lists.mcs.anl.gov] on behalf of
> nek5000-users at lists.mcs.anl.gov [nek5000-users at lists.mcs.anl.gov]
> *Sent:* Friday, October 24, 2014 10:18 AM
> *To:* nek5000-users at lists.mcs.anl.gov
> *Subject:* Re: [Nek5000-users] SYM and ON boundary conditions
>
>   Hello Oana
>
>  The "O" condition is fine. Is ON also same ?
>
>  In the SYM, is there no condition on the pressure ? Also it seems to me
> it should read
>
>  (grad(u).n).t
>
>  or in terms of matrix-vector products
>
>  t^T * grad(u) * n
>
>  Can you clarify please ?
>
>  Thanks
> praveen
>
> On Fri, Oct 24, 2014 at 8:00 PM, <nek5000-users at lists.mcs.anl.gov> wrote:
>
>>  Hi Praveen,
>>
>> This information will be in the new documentation soon to be posted. I
>> attached a small pdf of the section that interests you.
>>
>> I'd greatly appreciate appreciate if you let me know whether this was
>> accurate and helped cause I didn't get to check it thoroughly yet (that's
>> why the document is not up yet).
>>
>> Best,
>> Oana
>>  ------------------------------
>> *From:* nek5000-users-bounces at lists.mcs.anl.gov [
>> nek5000-users-bounces at lists.mcs.anl.gov] on behalf of
>> nek5000-users at lists.mcs.anl.gov [nek5000-users at lists.mcs.anl.gov]
>> *Sent:* Friday, October 24, 2014 5:41 AM
>> *To:* nek5000
>> *Subject:* [Nek5000-users] SYM and ON boundary conditions
>>
>>    Dear neks
>>
>>  Could you list the equations used for the SYM and ON boundary
>> conditions ?
>>
>>  Thanks
>> praveen
>>
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>
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