Drag reduction in turbulent flows by diutan gum: A very stable natural drag reducer

We study the ability of diutan gum (DG), a polysaccharide that belongs to a class called sphingans, to improve drag reduction (DR) in turbulent flows. This new drag reducer is very stable. Its efficiency in terms of DR does not significantly fall, which means that the polymer degradation or de-aggregation is not important at all. The onset of DR is independent of Reynolds number and concentration, typical from rigid materials for which the DR mechanism is called Type-B. The efficiency of DG solutions was compared with those of xanthan gum (XG) (rigid polymer) and polyethilene oxide (PEO) (flexible polymer) solutions.