[Nek5000-users] Maintaining order of perturbation

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

To add more, I found that near to the element boundary if I do the
averaging(dsavg()) the order cannot be maintained at those grid points.

Sayed

> Hi Paul,
>
> Sorry, I should have written it in more details.
>
> I have the base flow u_{base} calculated, already continuous across the
> elements. Now, I am trying to add perturbation doing to the base flow: u =
> u_{base}+\epsilon*u_{perturb} at each time-step. \epsilon being the order
> (e,g 10^-08) and u_{perturb} varies from 0 to 1 on each grid points.
>
>
> Best
> Sayed
>
>>
>> Hi Sayed,
>>
>> When you say it changed the order, how do you mean?
>>
>> It should indeed just averaged the interface values, so it
>> should be of the same order as the initial perturbation.
>>
>> Paul
>>
>>
>> On Tue, 14 May 2013, nek5000-users at lists.mcs.anl.gov wrote:
>>
>>> Hi all,
>>>
>>> I want to add perturbation of specific order (e.g. 10^-08) to the whole
>>> velocity field at each time-step. The velocity and pressure are both
>>> considered on GLL points. After adding perturbation, to have velocity
>>> as
>>> continuous function across the elements dsavg() is called (I found the
>>> info in one of the threads). I think it changes the order of
>>> perturbation
>>> near to the element boundary. I was wondering if there is other way to
>>> do
>>> so.
>>>
>>> This is my first mail to the group and I am using the code for my
>>> thesis.
>>>
>>> Thanks in advance!
>>>
>>> Best regards,
>>> Sayed
>>> MSc. COSSE
>>> KTH, Sweden
>>> FAU-Erlangen,Germany
>>>
>>>
>>>
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>>> Nek5000-users at lists.mcs.anl.gov
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>>>
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>
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