[Nek5000-users] Average in arbitrary direction

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

Hi Josh

Currently we use the interpolation stuff in g2gi() and hpts(). Just
have a look into these subroutines. The interpolation wrappers
intpts_setup() and intpts() are designed to provide a simple interface
making it easy to use. The parameters in intpts_setup have another
meaning (see in findpts.c) and you don't need to modify them unless
there is a good reason.

-Stefan


On 5/20/11, nek5000-users at lists.mcs.anl.gov
<nek5000-users at lists.mcs.anl.gov> wrote:
> Hello Aleks,
>
> I see the three routines I need, and I think I understand the basics
> of the functions (although I think it would still be nice to see an
> example if you are still working on updating it).
>
> I had some quick questions about the routine intpts_setup...it defines
> some variables npt_max, nxf, nyf, nzf.  Could you give a quick
> definition of the meaning of these 4 variables to the findpts_setup
> routine?
>
> Particularly, at least in the repo I have, npt_max is set to 256.  Do
> I need to change this if I'll be needing to interpolate onto more than
> 256 points (or does this mean something else)?
>
> Thanks,
>
> Josh
>
> On Thu, May 19, 2011 at 3:06 PM,  <nek5000-users at lists.mcs.anl.gov> wrote:
>> Hi Josh,
>>
>> yes, there are 3 intpts* routines from postpro.f that you can use. I have
>> an example but I need to update it for the current repo version of this
>> routines -- I'll send it to you once I modify and test it.
>>
>> Best,
>> Aleks
>>
>>
>> ----- Original Message -----
>> From: nek5000-users at lists.mcs.anl.gov
>> To: nek5000-users at lists.mcs.anl.gov
>> Sent: Thursday, May 19, 2011 9:21:03 AM
>> Subject: Re: [Nek5000-users] Average in arbitrary direction
>>
>> Hello Paul,
>>
>> This sound like exactly what I need.  I didn't find anything like
>> interp() while using grep in the repo--are you referring to the
>> routines found in postpro.f ??
>>
>> Thanks,
>>
>> Josh
>>
>> On Wed, May 18, 2011 at 3:59 PM,  <nek5000-users at lists.mcs.anl.gov> wrote:
>>>
>>> Hi Josh,
>>>
>>> You can use the interp() routines --- let me check if we have
>>> examples in the repo.
>>>
>>> These are somewhat expensive, so if you're also integrating in
>>> time (even over just 10 steps), it would pay to only interpolate
>>> the time-averaged data, rather than interpolating every timestep
>>> and then averaging the profiles.   However, I can understand that
>>> there are times you'd want the full time signal.
>>>
>>> The best integration formulae for periodic signals (e.g., in your theta
>>> direction and perhaps in z, if you have periodicity)
>>> is to simply sum the values, sampled uniformly in space (z or
>>> theta), and dived by n, the number of samples.   You do need
>>> to sample with sufficient density to capture all the wiggles ---
>>> another reason that time averaging has value.
>>>
>>> Paul
>>>
>>>
>>>
>>> On Wed, 18 May 2011, nek5000-users at lists.mcs.anl.gov wrote:
>>>
>>>> Hello Neks,
>>>>
>>>> I have looked at the turbChannel example for an example on planar
>>>> averaging.
>>>>
>>>> However, I was wondering if there was any advice  on how to do this if
>>>> the elements aren't exactly "nice"... (i.e., the elements may have
>>>> arbitrary rotations)
>>>>
>>>> Specifically, I have a pipe flow, and I am wanting to do an average in
>>>> the z (axial) direction.  My initial thoughts were to interpolate my
>>>> values to set R, theta components, and then average this along z.  I'm
>>>> stuck on the best way to do either one of these operations, however
>>>> (especially because I would like to use an integration rule to compute
>>>> the average in the z direction).
>>>>
>>>> If anyone could point me in the right direction, that would be a big
>>>> help.  Thanks!
>>>>
>>>> --
>>>> Josh Camp
>>>>
>>>> "All that is necessary for the triumph of evil is that good men do
>>>> nothing" -- Edmund Burke
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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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>
>
>
> --
> Josh Camp
>
> "All that is necessary for the triumph of evil is that good men do
> nothing" -- Edmund Burke
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