[Nek5000-users] Pn-Pn boundary condition

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

Hi all,

The Pn-Pn solver is implemented in plan4.f. Here are some useful references:

S. A. Orszag, M. Israeli, and M. O. Deville. Boundary Conditions for
Incompressible Flows. Journal of Scientific Computing, 1:75–111, 1986.

A.G. Tomboulides, J.C.Y. Lee, and S.A. Orzag. Numerical Simulation of
Low Mach Number Reactive Flows. Journal of Scientific Computing,
1997:139–167, 12.

J. L. Guermond. Nonstandard nonconforming approximation of the Stokes
Problem, I: periodic boundary conditions. International Journal of
Numerical Analysis and Modeling, 2:345–354, 2005.

I am happy to take your questions anytime.

Cheers
Stefan

On 10/6/11, nek5000-users at lists.mcs.anl.gov
<nek5000-users at lists.mcs.anl.gov> wrote:
>
> 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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>>> Nek5000-users at lists.mcs.anl.gov
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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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