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.

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This study performs a theoretical investigation into the problem of two-dimensional steady filmwise condensation flow on a horizontal tube with suction effects at the tube surface. An effective suction function is introduced to model the effect of the wall suction on the thickness of the liquid condensate film. The local condensate film thickness and the local Nusselt number are then derived using a simple series numerical method. The results show that the Nusselt number varies as a function of the Jakob number Ja, the Rayleigh number Ra, and the suction parameter Sw. It is found that the wall suction effect has a significant influence on the heat transfer performance. An analytical solution is derived for the mean Nusselt number for the case in which the wall suction effect is ignored. Finally, a closed-form correlation is presented for the mean Nusselt number subject to a wall suction effect.