How to generate random positioned nucleation sites
 

Dear Foamers,

I have been trying to do nucleate boiling simulation using phaseChangeHeatFoam. But the problem with the solver is that it generates a thin film of vapor at first and later on it breaks into tiny nucleation sites which gives us pseudo-feeling of nucleation. But, that is not correct way to simulate nucleation.

Hence, I want a way through which I can control nucleation sites. I would like to apply boundary condition in such a way that it generates vapor only at certain randomly positioned sites.
(Similar to what is explained in the figure which was proposed by yohei sato)

How can I provide such boundary condition of temperature or heat flux which depends on randomly generated cartesian coordinates on the given heated wall.