Re: [ESPResSo-users] Tube Flow Lattice Boltzmann

[Stefan Kesselheim]

Hi Wolfgang,
please try making the lbboundary longer than the box length.
It could be that the halo is flagged boundary and prevents anything from 
flowing.
Cheers
Stefan

On Apr 18, 2013, at 2:45 PM, Wolfgang Riefler <address@hidden> wrote:

> Hello all,
> 
> I am trying to simulate a flow within a cylindrical tube, using the Lattice 
> Boltzmann method.
> 
> I am using the following script:
> 
> 
> setmd box_l 54 18 18
> setmd time_step 0.005
> setmd skin 0.1
> 
> lbfluid agrid 1 dens 1 visc 10 tau 0.005 ext_force 0.04
> thermostat lb 0.0
> 
> lbboundary cylinder center 27.0 9.0 9.0 axis 1.0 0.0 0.0 radius 8.26 length 
> 27 direction -1
> 
> integrate x
> 
> According to the user guide this should define a cylindircal surface with 
> symmetry axis parallel to the x-axis, where all nodes outside the cylinder 
> are defined as boundary nodes.
> 
> However the fluid stays inert. If I change the direction to 1, I can see the 
> fluid flow outside the cylinder in x-direction as expected.
> 
> What am I doing wrong?
> 
> Thanks in advance,
> 
> Wolfgang