[ESPResSo-users] While using rigid body with virtual sites (position not inside a local plaquette dir 0...)

[Holst, Lena]

Hello everybody,

 

I want to create a rigid object, that is in influence of a poiseuille flow. For that I use the feature VIRTUAL_SITES_RELATIVE. After one of the first integrations I get the error message: 0: map_position_to_lattice: position (79.24 , 23.5, 959.13) not inside a local plaquette in dir 0 ind[dir]=79 rel=79.74 lpos=79.24.

 

To create the virtual particles, I have create a text file with xyz coordinates. This coordinates are in distance of 2 relative to the non-virtual particle. In the appendix there is a picture, which shows the arrangement of the virtual particles.

 

I´m using a dx=0.25, dt=0.1, agrid=1 and tau=1.

The dimension of the box is: 60, 49, 1920

 

The coordinates are not at grid knots. I think, that the feature vs_auto_relate arranges the particles to the nearest knots. Is that the case?

 

At the last integration, before get the error, the x-position of the non-virtual particle is 2016995220.46 and the x-position of one of the virtual particles is 0.4644. How could it be? I thought at every time step the distance between virtual and non-virtual particle be the same.

 

I have another question, too.

I want to give the rigid object a mass. The manual tells,  that the inertia tensor of the non-virtual particle in the center of mass needs to be adapted. Does it mean, I have to add the feature mass when I create the non-virtual particle (like: part 0 pos x y z mass 4)?

 

Thanks for help!

 

Lena Holst

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Kugel_Breite_dx0,25.PNG
Description: Kugel_Breite_dx0,25.PNG