OpenLB – Open Source Lattice Boltzmann Code Forums on OpenLB Bug Reports Multiphase flow in 3D using FreeEnergy LBM Reply To: Multiphase flow in 3D using FreeEnergy LBM

#9026
dirk.neethling
Participant

Dear Savis,

I am trying to simulate a film flow down an inclined (up to vertical) plane.
I think the Free Energy model using 2 components is the best approach, since I can then also model the surface tension and the fluid/air interface.
Using the multiComponent/microFluidics2d example as starting point, I then tried to reduce the domain to an inflow with a given velocity and an outflow with pressure balance. In the domain there would intially be air (component c2) with some of it being filled up the inflowing fluid (component c1).
Once I removed lattice3 from the example, i.e. remove the third component, thus reducing the flow to a binary case, nothing happens anymore, i.e. the inflowing fluid does not advance through the domain. I find this puzzling since the inflow boundary condition would surely force the fluid to move through the domain, right?
Using the approach in the multiComponent/youngLaplace2d example, with

rho = 1 = c1 + c2, => c1 = 1 – c2
and given that phi = c1 – c2 (see §4.4.2.1. Bulk Free Energy Model in the User Guide)
=> phi = (1 – c2) – c2 = 1 – c2 – c2, with psi = 0

However, as I mentioned the fluid is not moving through the domain, compared to the 3 component solution where the confluence of 2 or more inflows forces the column to move to the outlet.
Could you please indicate to me where my thinking is wrong?
Regards, Dirk