Separated-reattaching flow over a backstep with uniform normal mass bleed

The effect of normal mass bleed into the separated-reattaching flow behind a backward- facing step has been experimentally investigated. Results of LDA measurements showed that normal mass bleed suppressed the reverse horizontal velocity, the reverse flow rate, turbulence intensity, and Reynolds shear stress within the whole recirculating zone. An analysis of the distributions of vertical velocity and turbulence intensity indicates that the interaction between the injected fluid and the main stream began at 0.4 step height and became significant after 0.8 step height behind the backstep.