Unfortunately it’s not possible in the free energy model that’s currently implemented, and it would be quite a large undertaking to do so. If the effect of different densities is required then it would probably be easiest to implement the fluid-solid interaction in the SC model. I have discussed this before here.
The issue back then was that an indicator for the solid is required but not accessible within the lattice coupling. So a work-around will be required if you want to take this route.
I changed the contact angle by changing the virtual density in rayleighTaylor2d, but I’m not sure whether it reflects the fluid solid force. I don’t understand why changing the virtual density and the value of force will change the contact angle? I would appreciate it if you could answer my question.
This reply was modified 2 years, 10 months ago by Gloriousface.
To my understanding, changing the virtual density would affect the contact angle because the increased / decreased density gradient with the gas increases / decreases the solid-gas surface energy. So the solid-liquid area changes to reduce the total surface energy. This therefore affects the contact angle in a similar way to changing the fluid-solid force, which may be sufficient depending upon what you are doing.
However, I don’t believe it truly models the interaction with the solid because this would require a Neumann boundary condition in the density rather than a Dirichlet condition. There is more detail about this in chapter 9 of ‘The Lattice Boltzmann Method: Principles and Practice’ if you are interested.