[Nek5000-users] Question about method & error

Wed Apr 7 09:24:19 CDT 2010

On Wed, 2010-04-07 at 08:52 -0500, nek5000-users at lists.mcs.anl.gov
wrote:
> Frank,
> 
> Do you know the surface tension for your case?  Is it a function
> of temperature?

Hi Paul,

The surface tension depends linearly on the temperature, therefore the
shear stress (tangential to the interface) depends linearly on the
temperature gradient along (tangential to) the interface.

Cheers,
Frank 

> 
> Paul
> 
> 
> On Wed, 7 Apr 2010, nek5000-users at lists.mcs.anl.gov wrote:
> 
> > On Wed, 2010-04-07 at 06:21 -0500, nek5000-users at lists.mcs.anl.gov
> wrote:
> > Hi Frank,
> > 
> > There are several apps driving it.  At present, I think that the
> > version is slightly out of step w/ our current repo - but not far.
> > The original developer has moved on to a university and to other
> > projects, so has not been pushing it since September (though I used
> > it extensively in January for some tests).  I've been holding off
> > on pushing it further till I had more support.
> > 
> > If your shared interface has elements on either side that are
> > conforming it might also be possible to study the Marangoni
> > problem in the std. nek if you use the ALE formulation ---
> > If you use a fixed interface we would suffer from the fact
> > that the pressure would have a nullspace of dimension 2
> > since pressure on either side of the (rigid) interface
> > would be determined up to a constant.   This would be 
> > difficult for our solvers given that we've designed them
> > only to handle the case of an at-most one-dimensional nullspace.
> 
> Hi Paul,
> 
> The elements on both sides of the interface are conforming.  If the
> interface was free to move, but had a very high surface tension, high
> enough that it was essentially fixed, then perhaps that could work?  But
> then there could be problems with ill-conditioning with a very high
> surface tension.
> 
> > 
> > How complex is your domain?
> 
> Not very.  It consists of a liquid suspended (due to surface tension)
> between two metal posts.  The liquid is surrounded by a gas flow. 
> http://tetra.fluid.tuwien.ac.at/fmuldoo/public_html/temp/schematic-3d-liquid-bridge-2.png
> 
> I have gridded it using a block structured grid of 9 blocks, five in the
> liquid region and four in the gas. The terminology for the whole problem
> is a "liquid bridge".
> 
> Cheers,
> Frank
> 
> > 
> > Paul
> > 
> > On Wed, 7 Apr 2010, nek5000-users at lists.mcs.anl.gov wrote:
> > 
> > > On Tue, 2010-04-06 at 12:58 +0200, nek5000-users at lists.mcs.anl.gov
> > wrote:
> > > NEK-NEK stands for the coupling of two independent NEK instances. Unfortunately this is still an experimental feature but if you're interested in we can set up something for you.
> > 
> > Hello Stefan,
> > 
> > If I can make up a grid, is getting an instance of the NEK-NEK
> > capability working something you are willing to work with me to get
> > running?  Couple of questions: How experimental is the NEK-NEK
> > capability?  And is there a specific application or class of problems
> > driving it?
> > 
> > Cheers,
> > Frank
> > 
> > > 
> > > Stefan
> > > 
> > > 
> > > On Apr 6, 2010, at 12:54 PM, nek5000-users at lists.mcs.anl.gov wrote:
> > > 
> > > > Hello Stefan,
> > > > 
> > > > Thanks, that fixed it.  By the way, (from your earlier email) what does
> > > > NEK-NEK stand for?
> > > > 
> > > > Cheers,
> > > > Frank
> > > > 
> > > > On Tue, 2010-04-06 at 12:45 +0200, 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
> > > >> 
> > > >> _______________________________________________
> > > >> Nek5000-users mailing list
> > > >> Nek5000-users at lists.mcs.anl.gov
> > > >> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
> > > > -- 
> > > > Frank Herbert Muldoon, Ph.D. Mechanical Engineering
> > > > Technische Universität Wien (Technical University of Vienna)
> > > > Inst. f. Strömungsmechanik und Wärmeübertragung (Institute of Fluid
> > > > Mechanics and Heat Transfer)
> > > > Resselgasse 3
> > > > 1040 Wien
> > > > Tel: +4315880132232
> > > > Fax: +4315880132299 
> > > > Cell:+436765203470
> > > > fmuldoo (skype)
> > > > http://tetra.fluid.tuwien.ac.at/fmuldoo/public_html/webpage/frank-muldoon.html
> > > > 
> > > > _______________________________________________
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> > > > Nek5000-users at lists.mcs.anl.gov
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> > > 
> > > _______________________________________________
> > > Nek5000-users mailing list
> > > Nek5000-users at lists.mcs.anl.gov
> > > https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
> > -- 
> > Frank Herbert Muldoon, Ph.D. Mechanical Engineering
> > Technische Universität Wien (Technical University of Vienna)
> > Inst. f. Strömungsmechanik und Wärmeübertragung (Institute of Fluid
> > Mechanics and Heat Transfer)
> > Resselgasse 3
> > 1040 Wien
> > Tel: +4315880132232
> > Fax: +4315880132299 
> > Cell:+436765203470
> > fmuldoo (skype)
> > http://tetra.fluid.tuwien.ac.at/fmuldoo/public_html/webpage/frank-muldoon.html
> > 
> > _______________________________________________
> > Nek5000-users mailing list
> > Nek5000-users at lists.mcs.anl.gov
> > https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
> > _______________________________________________ Nek5000-users mailing list Nek5000-users at lists.mcs.anl.gov https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
> -- 
> Frank Herbert Muldoon, Ph.D. Mechanical Engineering
> Technische Universität Wien (Technical University of Vienna)
> Inst. f. Strömungsmechanik und Wärmeübertragung (Institute of Fluid
> Mechanics and Heat Transfer)
> Resselgasse 3
> 1040 Wien
> Tel: +4315880132232
> Fax: +4315880132299 
> Cell:+436765203470
> fmuldoo (skype)
> http://tetra.fluid.tuwien.ac.at/fmuldoo/public_html/webpage/frank-muldoon.html
> 
> _______________________________________________
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> Nek5000-users at lists.mcs.anl.gov
> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
> _______________________________________________ Nek5000-users mailing list Nek5000-users at lists.mcs.anl.gov https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
-- 
Frank Herbert Muldoon, Ph.D. Mechanical Engineering
Technische Universität Wien (Technical University of Vienna)
Inst. f. Strömungsmechanik und Wärmeübertragung (Institute of Fluid
Mechanics and Heat Transfer)
Resselgasse 3
1040 Wien
Tel: +4315880132232
Fax: +4315880132299 
Cell:+436765203470
fmuldoo (skype)
http://tetra.fluid.tuwien.ac.at/fmuldoo/public_html/webpage/frank-muldoon.html