Some Characteristics of Flow Past Backward Facing Steps Including Cavitation Effects

Backward facing steps were used to study experimentally the effects of expansion ratio and Reynolds numbers on the incipient cavitation indices. For small changes in the expansion ratio, significant changes in incipient cavitation index were observed. The effect of cavitation and expansion ratio on the frequency of vortex shedding and pressure distribution downstream of flow separation were also obtained. The dependence of the flow characteristics like the reattachment length, the frequency of vortex shedding and the pressure distribution downstream of the step were obtained under noncavitating conditions. In the present study, the range of Reynolds numbers has been extended to values which are normally encountered in prototype installations.