[ESPResSo-users] Tube Flow Lattice Boltzmann

[Wolfgang Riefler]

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