air molecules is generated in the liquid as the fluid pressure is diminished the fluid velocity decreases then each cavitation bubble undergoes a series of procedures of constriction rebound and collapse creating high pressure of several gpa and a high temperature of approximately up to 5 000 u00b0 c generating microjets in the collapsed bubbles and generating ultrahigh shock wavesand radicals isolated from the bubbles such as hydroxyl or hydrogen peroxide around the collapsed bubbles here the radicals ultrahigh shock waves and ultrahigh pressure microjets generated around the bubbles act like a micro reactor to oxidize decompose erode and cut ambient molecules with a high temperature of approximately 5 000 u00b0 c and a pressure of several gpa the microjets are several times more effective in oxidizing decomposing eroding and cutting than plain waterjets ejected into the air with equal jet power the relative intensity of the cavitation bubble cloud is defined by cavitation number u03c3 given by formula 2 wherein p 1 denotes a ejected waterjet pressure or upstream pressure p 2 denotes a discharged fluid pressure of a reactor or downstream pressure and p v denotes a saturated vapor pressure of a fluid in units of mpa the optimum conditions for generating a cavitation bubble cloud vary according to various parameters including existence form of bubble nuclei dissolved gas concentration fluid pressure and velocity in a reactor vapor pressure of a liquid surface tension coefficient of kinematic viscosity compressibility specific heat heat transfer latent heat turbulence a sufficient time for growth of cavitation bubbles and so on and the cavitation number u03c3 is generally in the range of 0 01 to 0 06 now potable water purification sterilization and control of water quality in a hatchery and red.