A study of swirling backflow and vortex structure at the inlet of an inducer

This paper describes a vortex structure at the inlet of an inducer which ap pears on the boundary of backflow region. The vortex structure was visualiz ed by the cavitation voids found by operating at cavitation number of sigma =0.050 and recorded by a high speed video. It was measured quantitatively b y two laser displacement sensors. The passing frequency and the shape of vo rtex filaments were determined from the outputs of the laser displacement s ensors which respond to the passage of the vortex cavitation. The results s how that the number of vortex filaments; their propagation angular velocity and radial location depend on the steady velocity profile at the inlet.