[ESPResSo-users] Proper use of command lbboundary

[Salvador H-V]

Dear ESPResSo users,

I want to simulate a quasi-2Dimensional suspension of finite-size spheres using Lattice Boltzmann.

In order to use LB, i am using a cubic-box for my simulations but the system is highly confined trough wall constraints.

 

agrid 1.0

bl 32

setmd box_l $bl $bl $bl

To constraint the spheres (diam = 1), I am using the following parameters:

set blz_wall [expr {2.0 * $diam}]

set wall1 [expr {$blz*0.5 - 1.5} ]

constraint wall  normal 0 0 1  dist $wall1 type 1

set wall2 [expr {-1.0*($wall1 + $blz_wall) } ]

constraint wall  normal 0 0 -1 dist $wall1 type 1

Although I am able to confine my system and run the simulation with the lbfluid command, when I try to include constrictions  for the fluid I get always the following error (I had tried different situations):

 *** Process received signal ***

Signal: Segmentation fault: 11 (11)

 Signal code: Address not mapped (1)

 Failing at address: 0x0

 *** End of error message ***

Segmentation fault: 11

I was wondering if it is possible to add fluid constraints/boundaries at the same position/coodinates that those of the wall constraints or should exist a gap between them? Is there any restriction in the distance-separation between the boundaries for the fluid?

Thanks a lot in advance,

Salvador HV