Re: [ESPResSo-users] terminal velocity for LB fluid

[Ulf Schiller]

On 09/27/2013 05:18 PM, Vincent Ustach wrote:
> These are all great answers, thanks everyone. It is definitely more of a
> physics question than a programming one.
>
> Ulf,
> My objective is to determine the constant g in the offset between the
> bare friction and effective friction of the system in reference to the
> above paper (Alrichs and Dunweg 1999, and again in Usta et al 2005). The
> velocity of a particle under an external force was measured and I can
> only assume a terminal velocity was somehow determined.
>
> Owen,
> I think simulating flow between two plates could give the desired
> effect, as long as the system was large enough in the direction normal
> to the plates. I'm going to try it.
>
> Stefan,
> This is a very interesting point but I need to look into the
> implications of it to see if it satisfies the my problem. My hunch is
> that it does.

Hi Vincent,

I think Stefan's solution is exactly what you can do to measure the 
settling velocity and the mobility/friction. In addition, you may want 
to fix the particle on the grid to capture the position dependence of 
the effective friction. Since ESPResSo uses linear interpolation, the 
effect is quite pronounced.

Flow between plates has a different Stokeslet of the point force, so 
that is more tricky but possible too.

Best,
Ulf

--
Dr. Ulf D. Schiller                        Building 04.16, Room 3006
Institute of Complex Systems (ICS-2)       Phone:   +49 2461 61-6144
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