[gmx-users] couette flow
schneemilch at yahoo.com
Wed Apr 23 15:56:32 CEST 2008
--- On Wed, 4/23/08, Berk Hess <gmx3 at hotmail.com> wrote:
> From: Berk Hess <gmx3 at hotmail.com>
> Subject: RE: [gmx-users] couette flow
> To: "Discussion list for GROMACS users" <gmx-users at gromacs.org>
> Date: Wednesday, April 23, 2008, 10:25 PM
> > Date: Wed, 23 Apr 2008 05:29:26 -0700
> > From: schneemilch at yahoo.com
> > Subject: RE: [gmx-users] couette flow
> > To: gmx3 at hotmail.com
> > --- On Wed, 4/23/08, Berk Hess
> <gmx3 at hotmail.com> wrote:
> > > From: Berk Hess <gmx3 at hotmail.com>
> > > Subject: RE: [gmx-users] couette flow
> > > To: schneemilch at yahoo.com
> > > Date: Wednesday, April 23, 2008, 7:27 PM
> > > > Date: Wed, 23 Apr 2008 02:34:49 -0700
> > > > From: schneemilch at yahoo.com
> > > > To: gmx-users at gromacs.org
> > > > Subject: [gmx-users] couette flow
> > > >
> > > > Hi,
> > > > Has anyone here used gromacs to simulate
> couette flows
> > > in slit pores? I can see that it would be
> possible to use
> > > the pull code but I would like to be able to run
> > > parallel. Any tips before I begin modifying
> source code
> > > would be greatly appreciated.
> > > >
> > > > Cheers, Matt
> > >
> > > I don't see what this has to do with the pull
> code. The
> > > pull code is made for forces between
> > > centers of mass of groups.
> > >
> > > There are already some external force options in
> the mdp
> > > file.
> > >
> > > But I don't see how you would set up an
> > > couette flow.
> > > In reality the flow is generated by a pressure
> > > In a simulation you can apply an external force
> or impose a
> > > velocity profile.
> > > But both these options make presumptions about
> > > force/flow profile.
> > >
> > > Berk.
> > >
> > Couette flow is shear driven, all you need is to have
> one pore wall moving relative to the other. I figure this
> could be done using the pull code by assigning each wall to
> a different group and using the pull code to increase the
> lateral distance between them at a constant rate. But it
> seems that the pull code does not work in parallel. Is
> there another way to prescribe the motion of one of the
> > Cheers, Matt
> Ah, sorry, I confused it with Poiseuille.
> The deform option does shear boundary conditions.
> But if you want to move real walls, there is currently no
> simple option that gives
> a group a constant velocity. The pull code should indeed do
> it. In the CVS version
> the pull code also works in parallel.
> BTW the reply address in your mail is your own address,
> instead of gmx-users,
> I don't you if you caused this, or if something is
> wrong on the server.
In that case I guess it would be easiest to switch to the CVS version. Thanks for the tip.
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