Re: [ESPResSo-users] pressure boundary condition

[Ulf Schiller]

Hi Markus,

have a look at the functions lb_outlet_x and lb_inlet_x in my gist code:
https://gist.github.com/uschille/8f65dd40572b2d943409

They implement pressure boundary conditions for in/outlets in the
x-direction. They can be easily modified for the other cartesian
directions. For inclined in/outlets it's a bit more complicated though.
The basic idea is to solve an equation system for the unkown populations
that satisfies the conservation laws plus appropriate conditions for the
non-equilibrium parts. For the latter, I don't think there is a
universal rule so it will depend on the specific application what works
best.

Best wishes,
Ulf

On 12/01/15 10:39, Markus Gusenbauer wrote:
> Dear users and developers,
> 
> we would like to implement pressure boundary conditions in order to
> simulate Poiseuille flow. The example poiseuille.tcl is quite limited as
> we would like to have more complex flow geometries with different
> in-/outflow directions.
> 
> What would be the best starting point to implement the boundary
> condition? Is there any appropriate literature that would fit for
> ESPResSo? Maybe someone has already started writing the code? Any
> experiences, ideas or suggestions?
> 
> Another important point would be the definition of more complex boundary
> shapes. Is it possible to set single lattice nodes as boundaries? We
> would like to use voxel data to set the boundary nodes. Again, where
> would be the best starting point for the implementation?
> 
> Any help would be appreciated!
> 
> Thanks,
> Markus
> 


-- 
Dr Ulf D Schiller
Centre for Computational Science
University College London
20 Gordon Street
London WC1H 0AJ
United Kingdom

Phone: +44 (0)20 7679 5300