STUDY OF DRAG REDUCTION IN FLOW THROUGH PACKED BEDS IN SMOOTH AND ROUGH PIPES.

This paper contains the experimental studies on drag reduction phenomenon due to the introduction of drag reducing agent (carboxy-methyl-cellulose) in viscous flows through packed beds in commercial rough steel pipe as compared to smooth perspex tubes. It has been observed that at low Reynolds numbers, the amount of drag reduction in rough pipe is approximately of the same order as that in smooth pipes, but at higher Reynolds number, considerable drag reductions have been observed in rough pipes as compared to smooth pipes at the same ratio of particle to tube diameter. The amount of drag reduction increases with the concentration in rough pipes.