[Nek5000-users] Question about method & error

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

Hello Stefan,

Couple of questions.  If using the PN/PN-2 method, are the variables
written out at the PN or PN-2 nodes?  Also, are the passive scalars
stored at the PN nodes?  

In the PN/PN method, is some filtering done to remove the spurious modes
from the pressure field?

By the way, are you in Europe?

Cheers,
Frank

On Tue, 2010-04-06 at 12:56 +0200, nek5000-users at lists.mcs.anl.gov
wrote: 
> One striking property of the implemented PN/PN method is that convergence
> is ensured for all pairs of approximation spaces. In other words, these spaces do not need be compatible, i.e. they do not need satisfy the LBB condition.
> 
> This is in contrast to the implemented PN/PN-2 method. Only compatible spaces for u and p are free of spurious modes.
> 
> hth,
> Stefan
> 
> 
> On Apr 6, 2010, at 12:45 PM, nek5000-users at lists.mcs.anl.gov wrote:
> 
> > Hi Frank,
> > 
> > On Apr 6, 2010, at 12:32 PM, nek5000-users at lists.mcs.anl.gov wrote:
> >> Am I correct in understanding that all components of velocity are
> >> stored at the same locations (the Gauss–Lobatto–Legendre points), while
> >> the pressure is located at the Gauss–Legendre points?  This being in
> >> contrast to a MAC type staggered grid, where each velocity component
> >> resides at different spatial locations.
> >> 
> > Yes that's correct!  In NEK two different methods are implemented:
> > 
> > PN/PN: (v,p) are defined on the GLL points
> > PN/PN-2: v is defined on the GLL points and p on the GL points
> > 
> > 
> >> VisIt could not read from the file
> >> "/home/fmuldoo/nek5_svn/examples/turbChannel-1/turbChannel0.f0001".
> >> 
> >> The generated error message was:
> >> 
> >> There was an error
> >> opening /home/fmuldoo/nek5_svn/examples/turbChannel-1/turbChannel0.f0001. It may be an invalid file.  VisIt tried using the following file format readers to open the file: Silo
> >> 
> >> When using the following metadata file:
> >> 
> >> NEK5000
> >> version: 1.0
> >> filetemplate:  turbChannel0.f%04d
> >> firsttimestep: 1
> >> numtimesteps: 1
> > It seems like you're using a wrong filetemplate. Please try again with:
> > filetemplate:  turbChannel%01d.f%04d
> > 
> > 
> > #Stefan
> > 
> > _______________________________________________
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> > Nek5000-users at lists.mcs.anl.gov
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> 
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-- 
Frank Herbert Muldoon, Ph.D. Mechanical Engineering
Technische Universität Wien (Technical University of Vienna)
Inst. f. Strömungsmechanik und Wärmeübertragung (Institute of Fluid
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