Phase Field in Fluids (pf)
The initial interface between the coating fluid and the air is automatically assigned to the boundaries between the two initial value domains. Set up the initial coating fluid domain in the inlet channel.
Initial Values, Fluid 2
1
In the Model Builder window, under Component 1 (comp1) > Phase Field (pf) click Initial Values, Fluid 2.
2
Select Domain 3 only.
Wetted Wall 1
1
In the Model Builder window, click Wetted Wall 1.
2
In the Settings window for Wetted Wall, locate the Wetted Wall section.
3
In the θw text field, type 68.5[deg].
Inlet 1
1
In the Physics toolbar, click  Boundaries and choose Inlet.
2
In the Settings window for Inlet, locate the Phase Field Condition section.
3
From the list, choose Fluid 2 (ϕ = 1).
4
Select Boundary 10 only.
Outlet 1
1
In the Physics toolbar, click  Boundaries and choose Outlet.
2
Select Boundaries 1 and 16.
Wetted Wall 2
1
In the Physics toolbar, click  Boundaries and choose Wetted Wall.
2
Select Boundary 2 only.
3
In the Settings window for Wetted Wall, locate the Wetted Wall section.
4
In the θw text field, type 74[deg].
By default, the phase-field model distributes surface tension uniformly across the fluid-fluid interface. When the phase densities differ greatly, the lighter phase can develop spurious velocity oscillations, leading to smaller time steps and longer computation times; shifting the surface tension toward the heavier phase can mitigate this. This is done by multiplying the surface tension force by
where ds,Fst is a mixing parameter defining the size of the transition zone.
To change averaging methods, you must first activate Advanced Physics Options.
1
Click the  Show More Options button in the Model Builder toolbar.
2
In the Show More Options dialog, in the tree, select the checkbox for the node Physics > Advanced Physics Options.
3
Click OK.
4
In the Model Builder window, under Component 1 (comp1) > Multiphysics click Two-Phase Flow, Phase Field 1 (tpf1).
5
Select the Shift surface tension force to the heaviest phase checkbox.