ABSTRACT

Cavitation called ‘mixing layer’ type appears in the core of vortices formed in the turbulent shear layers. One of the surprising characters of this phenomenon is related to the fact that it is produced in the zones of high static pressure. Users of valves of hydraulic control mechanisms are surprised to observe the occurrence of cavitation under average pressure, of the order of a few tens or even hundred bars. Interpretation of all results concerning the cavitation of valves and their values of σ should take into account this recovery of the kinetic energy. The hypothesis that the unsteady pressure field is independent of the Reynolds number would, in case of spectra of nuclei measured on models, lead to the same conclusions as those arrived at in the case of quasi-steady cavitation with separated entities. Unlike the mixing layer cavitation, vortex cavitation is the result of a rotating flow or is related to a rotary machine, a propeller, for example.