[Nek5000-users] Using Cartesian grid lookup table in Nekton

Wed May 30 14:42:14 CDT 2018

There is nothing spectral element specific here. You could do e.g. a trilinear interpolation but that's something you have to code yourself. 

-----Original message-----
> From:nek5000-users at lists.mcs.anl.gov <nek5000-users at lists.mcs.anl.gov>
> Sent: Wednesday 30th May 2018 21:26
> To: nek5000-users <nek5000-users at lists.mcs.anl.gov>
> Subject: Re: [Nek5000-users] Using Cartesian grid lookup table in Nekton
> 
> The question is how to read in a discrete data set defined in a finite difference grid in ffx or forcing in the .usr file. It seems like there will be some sort of interpolation to the spectral element grid. So yes, that is my question.
> 
> Thank you,
> Saikat
> <br clear="all" />Saikat Mukherjee,
> PhD Student,
> Paul Research Group - http://www.me.vt.edu/mpaul/ <http://www.me.vt.edu/mpaul/>
> Engineering Science and Mechanics,
> Virginia Tech.
> 
> On Wed, May 30, 2018 at 2:48 PM,  <nek5000-users at lists.mcs.anl.gov <mailto:nek5000-users at lists.mcs.anl.gov>> wrote:
> What’s your question? How to do the interpolation in your function f?
> 
> On 30 May 2018, at 20:17, "nek5000-users at lists.mcs.anl.gov <mailto:nek5000-users at lists.mcs.anl.gov>" <nek5000-users at lists.mcs.anl.gov <mailto:nek5000-users at lists.mcs.anl.gov>> wrote:
> 
> Hi,
> 
> Thanks for the reply. My problem is f is given as a discrete data set described in finite difference grid. I want to interpolate this to ffx like you said in my .usr file. Would like to know how to proceed.
> 
> Thanks,
> Saikat
> <br clear="all" />Saikat Mukherjee,
> PhD Student,
> Paul Research Group - http://www.me.vt.edu/mpaul/ <http://www.me.vt.edu/mpaul/>
> Engineering Science and Mechanics,
> Virginia Tech.
> 
> On Wed, May 30, 2018 at 1:36 PM,  <nek5000-users at lists.mcs.anl.gov <mailto:nek5000-users at lists.mcs.anl.gov>> wrote:
> Lets consider 
> 
> ffx = f(x,y,z)
> 
> here f is an user function (something you have to provide) which get evaluated at x,y,z (your grid points). Interpolation is required if f is given by a discrete data set. 
> 
> hth
> 
> 
> -----Original message-----
> > From:nek5000-users at lists.mcs.anl.gov <mailto:From%3Anek5000-users at lists.mcs.anl.gov> <nek5000-users at lists.mcs.anl.gov <mailto:nek5000-users at lists.mcs.anl.gov>>
> > Sent: Wednesday 30th May 2018 19:19
> > To: nek5000-users <nek5000-users at lists.mcs.anl.gov <mailto:nek5000-users at lists.mcs.anl.gov>>
> > Subject: Re: [Nek5000-users] Using Cartesian grid lookup table in Nekton
> > 
> > Hi,
> > 
> > Thanks for the reply. The look up table is in a finite difference grid. Are you saying I can still feed it to the .usr file and it should be fine?
> > 
> > Thanks,
> > Saikat
> > <br clear="all" />Saikat Mukherjee,
> > PhD Student,
> > Paul Research Group - http://www.me.vt.edu/mpaul/ <http://www.me.vt.edu/mpaul/> <http://www.me.vt.edu/mpaul/ <http://www.me.vt.edu/mpaul/>>
> > Engineering Science and Mechanics,
> > Virginia Tech.
> > 
> > On Sat, May 26, 2018 at 10:54 PM,  <nek5000-users at lists.mcs.anl.gov <mailto:nek5000-users at lists.mcs.anl.gov> <mailto:nek5000-users at lists.mcs.anl.gov <mailto:nek5000-users at lists.mcs.anl.gov>>> wrote:
> > Hi Saikat,
> > 
> > You can always do the reading from the look up table from .usr file, at once then feed the data to your ffx ffy and ffz through a common block.
> > 
> > On Thu, May 24, 2018 at 10:55 PM,  <nek5000-users at lists.mcs.anl.gov <mailto:nek5000-users at lists.mcs.anl.gov> <mailto:nek5000-users at lists.mcs.anl.gov <mailto:nek5000-users at lists.mcs.anl.gov>>> wrote:
> > Hey all,
> > 
> > Just following up on the query. Would appreciate any input.
> > 
> > Thanks,
> > Saikat
> > <br clear="all" />Saikat Mukherjee,
> > PhD Student,
> > Paul Research Group - http://www.me.vt.edu/mpaul/ <http://www.me.vt.edu/mpaul/> <http://www.me.vt.edu/mpaul/ <http://www.me.vt.edu/mpaul/>>
> > Engineering Science and Mechanics,
> > Virginia Tech.
> > 
> > On Tue, May 22, 2018 at 4:47 PM, Saikat Mukherjee <msaikat6 at vt.edu <mailto:msaikat6 at vt.edu> <mailto:msaikat6 at vt.edu <mailto:msaikat6 at vt.edu>>> wrote:
> > Hey Neks,
> > 
> > I have a forcing function which is in the form of a look up table in X-Y cartesian grid. I would like to use this forcing function in the 2-D fluid momentum equation that Nekton solves. Is there a way to do this in the .usr file or elsewhere?
> > 
> > Thanks,
> > Saikat
> > 
> > 
> > <br clear="all" />Saikat Mukherjee,
> > PhD Student,
> > Paul Research Group - http://www.me.vt.edu/mpaul/ <http://www.me.vt.edu/mpaul/> <http://www.me.vt.edu/mpaul/ <http://www.me.vt.edu/mpaul/>>
> > Engineering Science and Mechanics,
> > Virginia Tech.
> > 
> > 
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