COMSOL 6.4 - Mixing Rules

For flows with large viscosity or density ratios, replacing the default linear property averaging with a smoothed-Heaviside scheme can improve performance. This model averages fluid properties using smoothed Heaviside functions

where Vf,2 is the volume fraction of fluid 2 and lρ is a mixing parameter. A similar expression is used for the dynamic viscosity.

1

In the window, under click .

2

In the window for , locate the section.

3

Click to select row number 1 in the table, to select mixing rule for density.

4

In the dialog, choose from the list. In the lmix text field, type 0.9.

5

to continue with mixing rule for viscosity.

6

From the list, choose . Click .

The mixing parameter can be decreased to sharpen the interface, but that will increase the computation time for this example.