[Nek5000-users] Flow Rate Oscillation on 16384 cores

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

Hi JP,
Yes, but I was just thinking that the fact that you do not recover an 
exactly constant flow rate, while the algorithm in Nek in principle 
assures exact constancy, might have something to do with your problem. 
If you check the output of Nek (the logfile), there should be a line 
with the computed flow rates and the forcing amplitude (the line ends 
with something like "volflow"). Could it be that your postprocessing 
routines are somehow affected by the different numbers of processors?

philipp

On 2015-03-28 20:01, nek5000-users at lists.mcs.anl.gov wrote:
> Dear Philipp,
>
> The slight flow rate variations are probably due to quick way we
> calculate the flow rate.. this is calculated on custom files that
> contain data which was converted from the original nek dumps.. the mesh
> spacing is not constant in the y direction and probably causes some
> oscillations.. what I cannot understand is how changing the number of
> cores affects this oscillation so much in the region where more cores
> were used...
>
> Regards,
> JP
>
>
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