numerical simulaiton of falling liquid film flow

shoushi bo

i use vof model to simulate interfical waves on a falling liquid film. a low frequence disturbance should develop a solitary wave which consists of a roll wave and capillary waves.but in my simulation ,there is only roll wave and no capillary waves.i refined my mesh and selected high-accurate discretization scheme. i included the surface tension coefficient in the Phase interaction Panel. meanwhile Enable gravity.

How does the capillary waves appear? please give me some advice. Thanks in advance.