Re: [ESPResSo-devel] incorrect velocity scaling for slip lbboundary

[Ivan Cimrak]

Hi Kai,

Indeed I did the tests with LB_CPU. Sorry I forgot to mention this. (The 
tests were done with the current github version of the python branch, 
with LB and LB_BOUNDARIES compiled in).


Ivan


On 08/12/2017 11:08, Kai Szuttor wrote:
> Hi Ivan,
>
> I just checked your test with GPU LB and there the velocity comes out
> correct, so it seems to be a problem of CPU LB.
>
> I'll have a look.
>
> Cheers,
>
> Kai
> On Fri, Dec 08, 2017 at 08:56:03AM +0000, Ivan Cimrak wrote:
> > Hey guys,
> >
> >
> > Is it possible to have incorrect velocity scaling for slip boundary
> > conditions? I took an example script (attached) from section "10.10. Setting
> > up boundary conditions" from ESPResSo online documentation:
> >
> > http://espressomd.org/html/doc/lb.html
> >
> > I added the printing of the velocity near the right slip wall and after
> > reaching steady state it shows almost 100 times larger velocity as it is
> > supposed to be (0.941 or so instead of 0.01). This behaviour is linked with
> > lb timestep which was 0.01. Increasing to timestep=0.1 gives only 10times
> > higher velocity.
> >
> >
> > Could you comment on this?
> >
> >
> > Many thanks,
> >
> > Ivan