Dear All,
I am doing MD simulation of colloidal particles (size 100sigma-300sigma) to find the shearing viscosity using NEMD method. I have three questions regarding this:
(1) How can match my simulation results at high shear rates (say 10^7) to experimental results with comparatively
much lower shear rates? It seems the experimental values are reduced by several orders of magnitude.
(2) Are simulation results valid at high shear rates as they are far off equilibrium state?
(3) Would it be possible to provide me in.colloid (written in reduced units and are available in /examples folder with
LAMMPS source code) for some real material say starch solution or any polymer solution (dilute and concentrated)?
Although I have converted in.colloid for 3d, I some difficulty to run for real polymeric solutions particularly getting
various parameters such as dynamic viscosity (required in pair_coeff lubricate/brownian), Acc, Acs, sigma_cc, d1 in reduced units. I also would like to point out the time scales for colloidal particles and solvent particles will be very different as time-scale, t* = t (epsilon / m / sigma^2)^1/2. Will the simulation fine with say 50000 timesteps using several equilibration stages?
Thanks a lot if you could give your valuable opinion or refer me to some literature articles where I can find some answers,
Sincerely
Indrajit Bandyopadhyay
Project Staff, IIT Delhi, IN
This mailing list is primarily for questions about the code. It can not provide you with answers to broader questions about modeling and simulation strategies. For that, you should study the copious literature on NEMD simulations of rheology and also discuss your ideas with experienced scientists.
Dear All,
I am doing MD simulation of colloidal particles (size 100sigma-300sigma) to
find the shearing viscosity using NEMD method. I have three questions
regarding this:
(1) How can match my simulation results at high shear rates (say 10^7) to
experimental results with comparatively
much lower shear rates? It seems the experimental values are reduced by
several orders of magnitude.
(2) Are simulation results valid at high shear rates as they are far off
equilibrium state?
(3) Would it be possible to provide me in.colloid (written in reduced units
and are available in /examples folder with
LAMMPS source code) for some real material say starch solution or any
polymer solution (dilute and concentrated)?
Although I have converted in.colloid for 3d, I some difficulty to run for
real polymeric solutions particularly getting
various parameters such as dynamic viscosity (required in pair_coeff
lubricate/brownian), Acc, Acs, sigma_cc, d1 in reduced units. I also would
like to point out the time scales for colloidal particles and solvent
particles will be very different as time-scale, t* = t (epsilon / m /
sigma^2)^1/2. Will the simulation fine with say 50000 timesteps using
several equilibration stages?
please note, that there is not requirement at all to do these kind of
simulations in reduced units.
just put the units keyword with your preferred choice at the top of
your input, and use parameters in units corresponding to your choice.
axel.