# Grid Indepenceny check for Multiphase Multi-component Shan-Chen

Dear All,

I want to simulate a droplet in fully periodic 2D domain using MCMP Shan-Chen method. initialization is performed by inserting a square of one of the fluid in the center of the domain (rhoW = 1,rhoO=0.01), while the other fluid applied out of this square (rhoW = 0.01,rhoO=1). for a system size of 100x100 and relaxation time of 1 for both fluids, results of simulation converge to a circle of a droplet in the middle of system. Also the the initialization is a square with length 20 in the center of system. the selected G is 1.5. and psi function for force calculation is equal to density.
I want to get same results for a system size of 50x50 or 200x200, how it can be possible?

is there any grid in-dependency check for multi phase multi component simulation using Shan-Chen LB method in the literature?

If you are not interested in physical units you just have to double the length of your square when your domain is 200x200, and divide by two when is 50x50. If you want to work with the same physical units using different domain sizes just follow the instructions given in: http://wiki.palabos.org/_media/howtos:lbunits.pdf
I’m not sure if this answers you question. If not, let us know what do you want more specifically.

Dear LBMLeaner,

Did you write your own code or used opensource LBM solvers available?

Even I am trying to create an MCMP shan and chan model
Would like to discuss more how you achieved a density ratio of 100
Awaiting response

Regards

Sandeep

Dear edu__1313 and Sandeep,

I use same density for both fluids, which is 1. I want to get same results for two different system sizes. I mean same droplet size. based on the mentioned LB unit reference, I should change relaxation time (1 for 100x100 and 1.5 for 200x200) . However, for different system size results are completely different.