Re: [ESPResSo-users] Density in lbnodes

[Axel Arnold]

Dear Roya,

please, first don’t  bump developers personally an hour after you posted your question, especially not on christmas.

As to your question: as far as I know, our LB algorithm simply doesn’t propagate boundary nodes, so they stay with the initial condition, which is zero velocity and whatever density you put. In later versions, the fluid in the boundary nodes is also propagated, just doesn’t couple to the actual fluid in the accessible domain. Whatever values you read then in the boundary nodes are irrelevant.

Axel

On 24.12.2014, at 15:53, roya moghaddasi <address@hidden> wrote:

Hi Espresso users,

I have a cylinder in my simulation, and all of my particles and also fluid (LB) are inside the cylinder.

the velocity which I get with following instruction is zero in each node out of the cylinder, but density is 0.864 in all the nodes outside the cylinder,

[ lbnode $i $j $k print boundary u ]

Do you think is unusual or natural, I don't have anything outside the cylinder, so the velocity is zero but why the density is nonzero?

Any help would be highly appreciated.

Best

Roya

------------------------------------------------
JP Dr. Axel Arnold
ICP, Universität Stuttgart
Allmandring 3
70569 Stuttgart, Germany
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