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ludwig-cf / ludwig

A lattice Boltzmann code for complex fluids
https://ludwig.epcc.ed.ac.uk
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feature request #13

Closed JaSiddiqui closed 5 years ago

JaSiddiqui commented 5 years ago

I need your help in studying different viscosity ratios of binary fluid. I think it can be done by two distribution functions with two relaxation times. Viscosities are related to relaxation time, as a reference please see eq. 6.5 and 6.6 in "Inertial effects in three dimensional spinodal decomposition of a symmetric binary fluid mixture: A lattice Boltzmann study" By Kendon et al. (I am not sure, there may be some other method)

kevinstratford commented 5 years ago

I'll take a look at this; it may be a couple of weeks.

JaSiddiqui commented 5 years ago

Hi, Have you look at this enhancement? Is there any chance of doing that?

kevinstratford commented 5 years ago

Apologies, I haven't had a chance. There is a risk that I'm not going to have any time much before December. If you can't wait, it may be as well to have a look yourself.

It may be easiest to start in the "double distribution" version of the collision, lb_collision_mrt2_site() in collision.c as this already has access to the composition phi. It is then just a case of making the relaxation time a appropriate function of the composition via the viscosity.