ABSTRACT
Fixed or attached cavitation, i.e., entrained is the type mostly encountered on the profiles of rotary machines—pumps and turbines—and propellers. Contrary to the travelling bubble type of cavitation, the attached type needs no nuclei, or at most only one for its initiation. In pumps handling cryogenic liquids or petrol, decrease of cavitation due to thermodynamic effects is observed. Therefore, it is important to study such flows from this point of view because this phenomenon can be utilised to reduce the size and weight of turbomachines. In particular, this property is used in rocket motors. As a matter of fact, it is well known that laminar separation occurs only when there is an adverse pressure gradient and, therefore, a zone of lower pressure upstream of the separation. The minimum pressure, characterised by the pressure coefficient Cpmin, seldom occurs at the point of laminar separation, but at some point upstream of it.
