[Nek5000-users] Pn-Pn boundary condition

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

Josh is correct.

For Pn-Pn-2, you can set the outflow pressure in the particular case
where there is more than one exit.  (I've only done this once in my
life and would have to dig in a bit to recall out to do this..., but
would be happy to do so if that's of value.)

Paul



On Thu, 6 Oct 2011, nek5000-users at lists.mcs.anl.gov wrote:

> Zhu,
>
> As far as I understand it, boundary conditions for pressure aren't
> exactly SET, more so as they are computed so that div u = 0 (as Paul
> mentions in the note you included below).  So, as far as I know, there
> is no method to set, say, an inlet pressure with Nekton.
>
> Is this correct developers? (it's something I've always wondered myself)
>
> Josh
>
> On Thu, Oct 6, 2011 at 1:58 PM,  <nek5000-users at lists.mcs.anl.gov> wrote:
>> Hi all,
>>
>> I am wondering if there is any reference on the pressure boundary condition
>> for Pn-Pn case? I know Dr. Fisher has a 1997 JCP paper discussing the
>> Pn-Pn-2 setting.
>>
>> Also what subroutines/functions handle with the boundary conditions for both
>> velocity and pressure? Thank you,
>>
>> Zhu Wang
>> Virginia Tech
>>
>>
>> ----------------------------
>> Dear Fred,
>>
>> The pressure bcs are chosen to ensure div.U=0.
>>
>> For the Pn-Pn case, this involves addition of an appropriate inhomogeneity
>> that cancels the b.l. divergence that arises from std. splitting
>> formulations.
>>
>> For the Pn-Pn-2 case, there are no pressre bcs, only velocity bcs.
>>
>> Paul
>>
>> ----------------------------------
>> On Thu, 24 Jun 2010, nek5000-users at lists.mcs.anl.gov wrote:
>>
>>> Dear NEKs,
>>>
>>> I wanted to ask which boundary condition is used for the pressure in nek??
>>> are all pressure gradients normal to wall set tto zero?? because in my
>>> current simulation i have a pressure gradient normal to a wall and i am
>>> wondering why!?
>>>
>>> best, fred
>> ---------------------------
>>
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>
>
>
> -- 
> Josh Camp
>
> "All that is necessary for the triumph of evil is that good men do
> nothing" -- Edmund Burke
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