Applying the force only on fluid nodes, is that really what one wants?

[maxlevesque]

When we will deal with interfacial phenomena like adsorption/desorption not only in moment propagation but also in the LB steps, one should pay a lot of attention to where the forces are applied. Right now, in module_equilibration, we apply the forces where the node nature is fluid. What if node nature is interfacial? I am pretty sure that interfacial nodes are a subset of fluid nodes but as it is the external forces wont be applied on them.