HySF - Wet and Foam
"Wet and Foam" always requires an existing core fluid simulation.
Wet areas are those in which the fluid is touching the surface of the object. There, the wet emitter will create splash particles, and also foam.
Although, there is only one common export resource for the “Wet & Foam” emitter, RealFlow writes individual cache files: the wet files carry a “wet” suffix, the foam files the “_foam” extension.
For a workflow description visit the → "Wet and Foam" tutorial.