Turbulent drag reduction in dilute fiber suspensions: Mechanistic considerations

Both fibrous and polymeric additives, used alone or in combination, appear to affect primarily the fluid in the sublayer region adjacent to a solid surface, contrary to previous predictions. An analysis of fluid deformation modes shows tentatively why drag reduction levels become less sensitive to system scale when fibrous additives are employed, and why polymeric and fibrous additives may be more effective in combination than when either additive is used alone.