Re: [ESPResSo-users] Moving constraint

[Ulf Schiller]

Hi Rudolf,

if I understand correctly, you want to model a rigid body which is 
defined by a set of particle positions. I am not aware that this could 
be done out of the box with ESPResSo. There is a number of possible ways 
forward:

- Immersed boundaries/force coupling can be used with rigid objects, but 
one has to take care to treat the constraint forces, which I think is 
not implemented in ESPResSo.

- One could also think of filling the object with particles along the 
lines of Joost's extensions of the raspberry model.

- If the object has to be strictly impermeable, one has to apply 
boundary conditions on its surface. To this end, one has to determine 
the intersected links of the lattice dynamically in each time step. This 
could be done by variants of the marching cubes algorithm, and again I 
don't think this is implemented in ESPResSo.

Hope this helps.

Best wishes,
Ulf

On 12/7/2015 1:57 PM, Rudolf Weeber wrote:
> Hi,
>
> is anyone aware of an implementation of a moving constraint in Espresso, for example in the context 
> of "object in fluid" or "immersed boundaries"?
>
> What we need is a triangular piece of wall, where the corners of the triangle 
> are determined by the position of particles.
>
> Thanks in advance!
> Regards, Rudolf


--
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