Re: [ESPResSo-users] Simulation of fluid using LB-method

[Wink, Markus]

Hello everybody,

I tried to think about of the real position of the wall: 
"The (0, 0, 0) node of the LB lattice in Espresso is placed at (agrid/2, 
agrid/2, agrid/2)." 
In my case, I chose a_grid =1, so I put the walls at 1.5 and 51.5 in the 
simulation box. Thus the length of the simulation box is 53 in my case, gibing 
a channel width of 50. 
Am I right, or do you detect any mistake in my thoughts?

I am also puzzled with the negative slip velocity. Attached, you will find the 
simulation for a_grid = 0.5. I am not sure, but probably that helps.


Greets Markus


-----Ursprüngliche Nachricht-----
Von: address@hidden [mailto:address@hidden Im Auftrag von Ulf Schiller
Gesendet: Donnerstag, 30. Januar 2014 14:47
An: address@hidden
Betreff: Re: [ESPResSo-users] Simulation of fluid using LB-method

On 01/30/2014 02:33 PM, Georg Rempfer wrote:
> Hey all,
>
> I remember that we fixed the issue with the missing 0.5*h*F some years
> ago. For a flat bounce-back wall aligned with the lattice axis, the
> actual hydrodynamic no-slip wall is positioned in the middle between the
> last fluid node and the first wall node.

There is still a viscosity dependent slip velocity, cf. Eq. (20) in [He 
et al. (1997), J. Stat. Phys. 87, 115].

Cheers,
Ulf

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